Part III
Tutorials

7 Tutorials
 7.1 In-flight Tutorials
 7.2 FlightGear Tutorials
 7.3 Other Tutorials
8 A Basic Flight Simulator Tutorial
 8.1 Foreword
 8.2 Starting Up
 8.3 The First Challenge - Flying Straight
 8.4 Basic Turns
 8.5 Taxiing on the ground
 8.6 Advanced Turns
 8.7 A Bit of Wieheisterology
 8.8 Let’s Fly
 8.9 Dealing with the Wind
 8.10 The autopilot
 8.11 What Next?
 8.12 Thanks
 8.13 Flying Other Aircraft
9 A Cross Country Flight Tutorial
 9.1 Introduction
 9.2 Flight Planning
 9.3 Getting Up
 9.4 Cruising
 9.5 Getting Down
10 An IFR Cross Country Flight Tutorial
 10.1 Introduction
 10.2 Before Takeoff
 10.3 Takeoff
 10.4 In the Air
 10.5 Getting Down
 10.6 Epilogue
11 A Helicopter Tutorial
 11.1 Preface
 11.2 Getting started
 11.3 Lift-Off
 11.4 In the air
 11.5 Back to Earth I
 11.6 Back to Earth II

Chapter 7
Tutorials

If you are new to flying, an advanced simulator such as FlightGear can seem daunting: You are presented with a cockpit of an aircraft with little information on how to fly it.

In real life, when learning to fly you would have an instructor sitting next to you to teach you how to fly and keep you safe.

While we cannot provide a personal instructor for every virtual pilot, there are a number of tutorials available that you can follow to become a proficient virtual pilot.

7.1 In-flight Tutorials

FlightGear contains an in-flight tutorial system, where a simulated instructor provides a virtual ‘lesson’. These vary between aircraft from simple tutorials teaching you how to start the engines on the aircraft, to full lessons teaching you how to fly for the first time. To access tutorials, Select Start Tutorial from the Help menu.

The tutorial system works particularly well with the Festival TTS system (described above).

For simplicity, run tutorials with AI aircraft turned off from the Options item on the AI/ATC menu. Otherwise, ATC messages may make it difficult to hear your instructor.

Each tutorial consists of a number of discrete steps which you must complete. Your instructor will provide directions on how to complete each step, and observer how you perform them, providing additional guidance if required.

Within a tutorial, to ask your instructor to repeat any instructions, press ‘+’. You can pause the tutorial at any time using the ‘p’ key. To stop the tutorial select Stop Tutorial from the Help menu.

7.1.1 Cessna 172P tutorials

If this is your first time flying, a number of tutorials exist for the Cessna 172P designed to teach you the basics of flight, in a similar way to a real flight school. The tutorials are based around Half-Moon Bay (KHAF) and Livermore Municipal (KLVK) airports near San Francisco. Both these airports are provided in the base package. To start the tutorials, select the Cessna 172P aircraft, and a starting airport of KHAF or KLVK, using the wizard, or the command line:

$ fgfs --aircraft=c172p --airport=KHAF

When the simulator has loaded, select Start Tutorial from the Help menu. You will then be presented with a list of the tutorials available. Select a tutorial and press Next. A description of the tutorial is displayed. Press Start to start the tutorial.

7.2 FlightGear Tutorials

The following chapters provide FlightGear specific tutorials to take the budding aviator from their first time in an aircraft to flying in the clouds, relying on their instruments for navigation. If you have never flown a small aircraft before, following the tutorials provides an excellent introduction to flight.

Outside of this manual, there is an excellent tutorial written by David Megginson – being one of the main developers of FlightGear – on flying a basic airport circuit specifically using FlightGear. This document includes a lot of screen shots, numerical material etc., and is available from

http://www.flightgear.org/Docs/Tutorials/circuit.

7.3 Other Tutorials

There are many non-FlightGear specific tutorials, many of which are applicable. First, a quite comprehensive manual of this type is the Aeronautical Information Manual, published by the FAA, and available at

http://www.faa.gov/ATPubs/AIM/.

This is the Official Guide to Basic Flight Information and ATC Procedures by the FAA. It contains a lot of information on flight rules, flight safety, navigation, and more. If you find this a bit too hard work, you may prefer the FAA Training Book,

http://avstop.com/AC/FlightTraingHandbook/,

which covers all aspects of flight, beginning with the theory of flight and the working of airplanes, via procedures like takeoff and landing up to emergency situations. This is an ideal reading for those who want to learn some basics on flight but don’t (yet) want to spend bucks on getting a costly paper pilot’s handbook.

While the handbook mentioned above is an excellent introduction on VFR (Visual Flight Rules), it does not include flying according to IFR (Instrument Flight Rules). However, an excellent introduction into navigation and flight according to Instrument Flight Rules written by Charles Wood can be found at

http://www.navfltsm.addr.com/.

Another comprehensive but yet readable text is John Denker’s ”See how it flies”, available at

http://www.av8n.com/how/.

This is a real online text book, beginning with Bernoulli’s principle, drag and power, and the like, with the later chapters covering even advanced aspects of VFR as well as IFR flying.

Chapter 8
A Basic Flight Simulator Tutorial

8.1 Foreword

Aviation is about extremes:

The aircraft used in this tutorial is the Cessna 172p. This is the aircraft used in many real life flight schools and a great airplane to fly.

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The following articles complement this tutorial and will answer most questions that may arise as you read through. The first one in particular is a good introduction to the airplane’s main components and controls:

This tutorial is accurate to the best of my knowledge, but will inevitably contain some mistakes. I apologize in advance for these.

8.2 Starting Up

There are a number of different ways to start FlightGear based on your platform and the distribution you are using.

8.2.1 MS Windows

On MS Windows, FlightGear has a GUI Wizard in which you can choose your aircraft and starting postion. First choose the Cessna 172p airplane as shown below. To match this tutorial do not choose the 2D panel version. (You may however find in the future that the 2D version is more appropriate for training). Click the Next button to choose your airport.

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You can start from any airport for this tutorial, but I will assume that you will start from FlightGear’s default airport of San Francisco (KSFO):

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Once you have selected KSFO and clicked on the Next button, you can set any number of options for the simulator. For your first flight, I suggest starting at noon. I would also recommend that you start with a small resolution of 800 × 600. Later on, you can play around with the options and use a higher resolution, but this obviously adversly affects performance. Click on the Run button and FlightGear will start with the options you selected.

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If you have problems running the latest version FlightGear on your Windows system, you may want to try an earlier version with lower graphics requirements (for example 0.9.8). You can find previous releases on the FTP mirrors mentioned at the top of the FlightGear download page: .

If you are running under Windows Me and the flight simulator suddenly starts stuttering, with the frame rate dropping, try killing all tasks except Explorer and Systray before you launch FlightGear. If one of the tasks you kill is an antivirus or such protection software, this is an obvious security risk. Also, on one Windows Me machine, a FlightGear of 800 × 600 yielded good results, while a lower resolution of 640 × 480 triggered much lower FPS levels (Frames Per Second).)

8.2.2 Linux and other unices

On Linux and other Unix-like systems, you may have to run FlightGear from the command line. If you have installed FlightGear but cannot find it in your menu system, try the following:

8.2.3 In the dark?

Without the --timeofday=noon option, FlightGear will start at the current time in San Francisco - often night-time if you are in Europe. To change the time of day in the simulator to daytime, select Environment->Time Settings from the menu and select Noon.

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If running FlightGear from a menu (e.g. under KDE or Gnome), you can edit the FlightGear launch icon properties and change the simple fgfs fgfs command to something like fgfs --timeofday=noon --geometry=1024x768, or include whatever command options you wish. Further details of the command line options can be found in Chapter 4, Takeoff: How to start the program.

8.3 The First Challenge - Flying Straight

Once FlightGear is started you will see the following window and hear the sound of an engine:

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On startup, the aircraft is at the end of the runway with the engine running at low power. The airplane will occasionally tremble a little, but it won’t move.

About the keyboard.

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Press v, to view the aircraft from the outside. Type v repeatedly to scroll through a number of different views until you return to the cockpit. Typing V will cycle backwards through the views.):

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In real life, we would have inspected the airplane all around to check everything is working, nothing is hampering the moving parts, and nothing is obstructing the instrument openings. In the simulator, this is already done for us before we start.

Hold the Page Up key down for about eight seconds. You will hear the engine sound rise.

The airplane will start accelerating down the runway. As it does so, it will drift to the left, before finally taking off, banking to the left, falling to the ground and crashing (probably).

You can see a replay of the crash using the View -> Instant Replay menu. Click the Replay button at the bottom of the dialog window, then use v and V to see the airplane from the outside. The picture below shows the end part of the flight. You can take a snapshot by typing the F3 key. You can also use the F10 key to toggle the menu bar on or off.

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Having observed your crash, exit from FlightGear(using File->Quit) and restart the simulator using the same options as before.

In order to fly straight you need the airplane’s control yoke:

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You can control the yoke using a joystick, or by moving the mouse. To use the mouse you need to be in mouse yoke mode. Get in that mode by pressing Tab. The mouse cursor becomes a + sign. Move the mouse and see the yoke moving accordingly. Type v to see the plane from the outside. If you move the mouse again you will see the tail elevator and the ailerons at both wings ends move. If your viewpoint is too far from the aircraft to see any movement, type x a few times to zoom in. Type X to zoom back out. Ctrl-x returns the view to the default zoom level. Type V to change the view back to the cockpit.

Pressing Tab again gets you in mouse view mode. In this mode the mouse cursor will be a . sign. This allows you to look around easily by moving the mouse. Clicking the left mouse button will re-center the view. You can also change your view direction in the normal and yoke modes by holding down the right mouse button and moving the mouse. A further press of Tab will return you to the normal mouse mode.

To summarize, the Tab key cycles the mouse through three modes:

Try taking off again using the mouse to control the yoke. Press Tab to put the mouse in yoke mode (+pointer shape) and raise the engine throttle to maximum by holding the Page Up key down. Do not try to keep the airplane rolling straight on the runway using the mouse/yoke. Let it drift leftwards. Wait till it rises in the air. Then use the mouse to try and get the airplane to fly straight. (If you want to control the airplane on the ground see section 8.5.)

You will find that you must prevent the airplane from banking to the left:

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... or to the right:

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... or from plunging to the ground:

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Try to fly more or less straight, with the horizon stable slightly above the airplane nose:

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Whatever your skills at video games or simpler simulators, you will probably not succeed at first. The airplane will crash, probably quite soon after take-off. This is the moment where most candidates get desperate and abandon trying to fly a simulator or a real aircraft. Just hold tight and keep trying. Eventually you will develop a feel for the subtle control inputs required.

The most common error is moving the mouse forwards to bring the nose up. In fact, you must pull the yoke by moving the mouse backwards to do this.

Equally, when you want to lower the airplane’s nose, you must move the mouse forwards. This can seem odd, but all airplane control yokes are designed that way. With time, you will wonder how you every thought it worked any other way. You will also find that small mouse movements have a large effect on the aircraft. You may find that decreasing your mouse sensitivity may help initially.

If you have difficulty visualising this, the following analogy may help. Imagine a soccer ball is on your desk and you have “glued” your hand to the top of it. If you move your hand forwards the ball will roll forwards and your fingers will point to to the desk. If you move your hand backwards the ball will roll back and your fingers will now point up at the ceiling. Your hand is the airplane:

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Another common error is the assumption that the control inputs directly match airplane bank. In other words, you believe if the control yoke is level, the airplane will fly level. This is not true. The yoke controls the rate at which the airplane banks. If the airplane is banked 20˚ to the left and the control yoke is level, the airplane will stay banked at 20˚ left until some other force affects it. If you want to return the airplane to level flight, you have to turn the control yoke slightly to the right (move the mouse slightly rightwards) and keep it slightly to the right for a while. The airplane will turn slowly rightwards. Once it is level with the horizon, bring the control yoke level too. Then the airplane will stay level (until some other force changes its orientation).

A third error is trying to find “the right position” for the yoke/mouse. Naturally, you will want to find the fine tuning that will leave the airplane fly straight. Actually there is no such ideal yoke position. The airplane is inherintely unstable in the air. You must constantly correct the airplane’s attitude and keep it flying straight with tiny movements of the mouse. This may seem to take all your concentration intially, but just like driving a car, keeping the aircraft straight and level will soon become second nature. For longer flights, you will eventually use the autopilot to keep the airplane level, but this is outside the scope of this tutorial.

To help fine-tune your senses to the control inputs required, keep your eyes on the outside scenery and not get fixated on the instruments or the yoke. Check the angle of the horizon and its height above the airplane’s nose. The horizon line and the airplane engine cover are your main flight instruments. Look at the instrument panel only once in a while.

While the mouse is in yoke control mode (+ pointer shape), don’t move it close to the FlightGear window edges. Once the mouse leaves the window, it stops controlling the aircraft, often at the worse possible moment! If you wish to use the mouse outside of the window, first go back to standard mouse mode by pressing Tab twice.

You can also control the yoke using the four keyboard arrow keys or the keypad 8, 2, 4 and 6 keys. While initially this may seem easier than the mouse, you cannot make the very fine adjustments required for accurate flying, so it is much better to persevere with the mouse.

You may hear beeping sounds while flying around the airport. These are landing aid signals. Don’t worry about them for the moment.

You will know that you have mastered this when you can make the aircraft climb steadily in the air. The next step is to learn to keep the aircraft at a constant altitude, or to make it ascend or descend slowly and under your control.

Keeping the aircraft at a constant altitude involves observing the altimeter and making small changes with the mouse forwards or backwards to stop the aircraft ascending or descending respectively.

The altimeter instrument is at the middle top of the instrument panel. The long needle shows hundreds of feet, the short needle shows thousands of feet. The altimeter below shows an altitude of 300 feet, approximately 100 meters.

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As you ascend or descend the altimeter will change accordingly, turning anti-clockwise as you descend, and clockwise as you gain height. If you see the altimeter “unwinding” you will be able to tell that you are losing height and move the mouse backwards slightly to raise the nose. After a while you will notice that when flying level the nose of the aircraft is always in the same position relative to the horizon. This is the aircraft attitude for level flight. By putting the nose in that same position, you will achieve almost level flight without having to reference the instruments. From there you can fine-tune your altitude.

Beware: an altimeter does not automatically show the absolute altitude above sea level. You must adjust for the local air pressive. The little black knob on the lower left side of the altimeter allows you to adjust the altimeter. Start FlightGear and stay on the ground. Click (in normal mouse mode) inside the black knob. A click on the left half makes the altimeter turn back. On the right half the altimeter turns forward. Use that little knob to tune in the current altitude. The principle is you use the knob when you are sure about the altitude. If you know you are at 1,100 feet altitude, tune in 1,100 feet on the altimeter. Clicking with the middle mouse button makes the knob turn faster, or you can use the scrollwheel on your mouse. Type Ctrl-c to see the two button halves highlighted.

To make settings the altimeter easier, airports advertise their altitude in various ways. They may provide a radio service (called ATIS in the USA) to broadcast the current air pressure at sea level. This is expressed in inches of mercury. The altimeter contains a small scale inside which is calibrated in this way. You can set your altimeter using this scale. Alternatively, if you are on the ground and know the altitude of the airport, you can simply adjust your altimeter until it displays the correct altitude.

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Note that there is an important difference between “altitude above sea level” and “altitude above the ground”. If you fly near Mount Everest at an altitude of 24,000 feet above sea level (AMSL), your altitude above the ground (AGL) will be much less. Knowing the altitude of the ground around you is obviously useful.

8.4 Basic Turns

While if you had enough fuel you could return to the same airport by flying straight head for thousands of miles, being able to change direction will make your flying more enjoyable and useful.

Once you are able to fly more or less straight, it is time to learn to turn. The principle is simple:

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To turn, you do not need high levels of bank. 20˚ is more than enough for a safe and steady turn. The turn coordinator indicates your angle of bank by showing a depiction of your aircraft from behind. The picture below shows the turn coordinator when the airplane is banked 20˚ to the right. You can also tell the bank angle by observing the angle of the horizon.

Try the following: keep the airplane banked around those 20˚ for a few minutes and keep your eyes outside the aircraft You will see the same ground features appear again and again, every 120 seconds. This shows you need 120 seconds to make a 360˚ turn (or 60 seconds for a 180˚ )turn). This is particularly useful when navigating. Whatever speed the airplane is flying, if you bank at 20˚ you always need 60 seconds to make a 180˚ turn in the Cessna 172P.

So, by banking the airplane to the left or to the right, you make it turn to the left or to the right. Keeping the airplane level with the horizon keeps it flying straight.

The little purple ball in the bottom of the turn indicator shows the sideways forces. In real life you would feel these as your turn, however it is not possible to simulate these, so you must simply keep an eye on the ball. If you turn neatly (using the rudder a little bit), the ball will remain centered. If the ball is pushed say rightwards, this means you the pilot too are pushed rightwards. Like in a car turning to the left. During a neat turn in an airplane, even a strong turn, the passengers never endure a sideways force. They are only pushed a little harder on their seats by the centrifugal force.

By experimenting you will notice you can make much steeper turns by banking the airplane to high angles and pulling back on the yoke. Turns at over 60˚ bank angle are the realm of aerobatics and military flying, and dangerous is aircraft such as the Cessna.

8.5 Taxiing on the ground

While FlightGear starts you by default conveniently lined up on the runway and ready to go, you may be wondering how to get your aircraft from its hangar, along the taxi-ways to the runway. This is taxiing.

The picture below shows the instrument. It displays how fast the engine is turning in hundreds of revolutions per minute (RPM).

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Type the Page Up key a few times, until the tachometer is showing 1,000 RPM (as shown above). If required type the Page Down key to decrease the engine speed.

At roughly 1,000 RPM, the airplane will move forward on the runway, but it will not accelerate and take off.

Type the “.”key (Shift-; on Azerty keyboards). The airplane will make a sharp turn to the right. If you keep the “.”key down the airplane will halt. When you type the “.” key, you are activating the brake on the right wheel of the airplane.

To activate the brake on the left wheel, use the “,” key.

The “,” and “.” keys simulate two brake pedals located at your feet on a real airplane. Using the throttle and the brake pedals you can control the speed of the aircraft and cause it to turn on the ground.

The brakes can be very useful when taxiing slowly on the runway. You can also steer the nose-wheel of the aircraft. In a real airplane this is done by pushing the rudder pedals with your feet. You push with your feet on the side you want to turn towards. If you don’t have real rudder pedals, there are two ways to control the virtual rudder pedals:

Start the simulator, Type v or V to view the airplane from the outside and keep x down a couple of seconds to zoom in on the airplane. Look at the front wheel and keep keypad 0 down. Then keep keypad Enter down. See the front wheel turn. Press Tab to get in yoke control mode (+ pointer shape). Keep the left mouse button down to get in rudder control mode and move the mouse to the left and to the right. Note that the rudder, that big vertical control surface at the rear of the plane, moves together with the front wheel.

I tend to control the rudder pedals using the mouse while the front wheel is on the ground and use the keypad 0 and Enter keys once it has lifted off. In other words: I keep the left mouse button down while the front wheel is on the ground. This allows for a precise and easy rudder control on the ground. Then I simply release the left mouse button once the front wheel lifts off.

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8.5.1 Airspeed

Just like driving a car, it is good to know how fast you are traveling. The aviation equivalent of a speedometer is the airspeed indicator (ASI), calibrate in nautical miles per hour (knots).

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A knot is 1.85325 kilometer/hour. So, if you want to have a rough idea of your speed in flight expressed in km/h, multiply the knots displayed by 2. A knot is 1.15115 miles per hour, so very roughly, 1 knot is 1 mph. Note that some aircraft ASIs (in particular the Piper J3 Cub) display mph instead of knots.

The airspeed indicator displays the speed of the aircraft compared to the surrounding air, not the speed compared to the ground like a car speedometer does. If the plane is halted on the ground and there is a 10 knot wind blowing from straight ahead, the airspeed indicator will display 10 knots airspeed, although the plane will not be moving relative to the ground.

When the airplane rolls over the runway at more than 40 knots, you must prevent the front wheel from touching the ground. The nosewheel is not designed for high speeds and in real life would shimmy and wear out.

During take off, once over 40 knots you can make the front wheel leave the ground by pulling back gently on the control yoke. Don’t turn sharply at high speed on the ground. Doing so may cause the aircraft to tip over.

The picture below shows the front wheel slightly lifted. Don’t overdo this. Keep the airplane’s white nose cover well below the horizon. You just need to lift the plane’s nose very slightly.

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Question: if the front wheel no longer touches the runway, how do you steer the airplane? Answer: still using the rudder pedals. As mentioned above, the rudder pedals are linked to both the nose-wheel and the tail rudder, that big vertical moving part at the tail of the plane:

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At airspeeds above 40 knots, the rudder has enought air-flow over it to steer the airplane.

Note the front wheel and the tail rudder don’t make the airplane turn at exactly the same rate. So when the rudder takes over the front wheel, you must adapt the rudder pedals angle. That means fast typing keypad 0 and keypad Enter (or hold the left mouse button down and tightly control the rudder with the mouse).

Once you’ve become familiar with the nose-wheel and rudder, you can use these new controls to keep the airplane straight on the runway during take-off.

Say the airplane is heading too much to the right. You type keypad 0 a few times to make it turn back to the left. Don’t wait till the aircraft has straightened up completely. Type keypad Enter before the aircraft reaches the direction you wish to travel. Otherwise you will find that you will over-correct and have to turn back again. If you use the mouse, such corrections are much easier and more precise.

To summarise: two methods exist to steer the airplane on the ground: the differential brakes on the side wheels and the rudder pedals. This control redundancy is very common in aviation. If one method fails, you still have another method available to perform the task.

You may be wondering why the aircraft drifts to the left when it rolls on the ground, forcing your to compensate with a little push on the right rudder pedal? The main reason is the flow of air produced by the propeller. It blows along the airplane body, but also corkscrews around the airplane fuselage. The upper part of that slight vortex pushes the vertical tail to the right. This causes makes the front of the aircraft to yaw to the left.

You can center all yoke and rudder controls by typing 5 on the keypad. This is a good preflight precaution. Sometimes it can “save your life” in flight if you find yourself with controls all over the place!

8.6 Advanced Turns

As with turning on the ground, there are two methods of turning in the air. You can use the wing ailerons (steered by the yoke/mouse) as described above or you can use the tail rudder (steered by the rudder pedals / the keypad keys /0 and Enter.

Why two ways? Partially for redundancy, but mainly because they are complementary. The main effect of the rudder is yaw (rotation around the vertical axis), while the main effect of the ailerons is roll (rotation around the longitudonal axis).

When you turn in flight, using the ailerons, you still need the rudder a little bit. You add a little bit of rudder. This allows you to compensate for the adverse yaw created when you roll using the ailerons. In a real aircraft, you can feel this sideways motion. In the simulator, you can check this visually on the turn coordinator. In the picture below the little ball is pushed rightwards during a strong turn to the right using the ailerons. That means you the pilot endure a rightwards force too. You can compensate this by pushing the right rudder pedal (type the keypad Enter key a few times). In normal flight you should use the rudder to keep the little ball centered.

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So, in normal flight use the ailerons to turn, while close to the ground at low speed use the rudder. However, one method never completely cancels out the other. You still need the rudder at high altitudes and speeds. Reciprocally you have to use the ailerons a little bit when close to the ground, to keep the wings level with the horizon.

Even when taxiing, you should use the ailerons. Otherwise, strong winds can blow the aircraft onto its side. To counteract this, your should turn the ailerons into the wind. This raises the aileron in the wind, helping to keep the wing down.

You should avoid making quick and agressive movements of the rudder. On the ground at high speed this can make the airplane turn too sharply. In flight at low speed it can cause a very dangerous type of stall. In flight at high speed it can cause all kinds of aerodynamic and physical discomfort. Instead, make gentle movements of the rudder.

I recommend you practise turning with the rudder in flight. Fly at a low speed of about 70 knots. Try to keep the altitude stable by increasing and decreasing the engine power. Use the rudder to turn towards a ground feature and maintain a heading, then turn the aircraft towards a new heading. See how the plane yaws. Learn to anticipate rudder control. Don’t try to make steep turns. Use the yoke/ailerons to keep the wings level constantly.

8.7 A Bit of Wieheisterology

Wieheisterology comes from the German phrase “Wie heit Er” – “What’s that name”. This section is about gauges, switches and controls of the aircraft. While in the simulator you can take off and land a basic airplane with just the engine throttle and the yoke, but you will need all the controls to perform securely and efficiently.

8.7.1 Engine control

An airplane engine is designed for simplicity, reliability and efficiency. Rather than use advanced electronic ignition and fuel injection systems found in modern cars, they instead use older technology that doesn’t rely on electrical power. That way, the plane can still fly even if it suffers complete electrical failure.

Magneto

On the bottom left, below the instrument panel you will find the magneto switch and engine starter:

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To see the switch, either type P to get the schematic instrument panel or type Shift-x to zoom out (x or Ctrl-x to zoom back in).

You can move the switch with the { and } keys (use the Alt Gr key on Azerty keyboards).

You are probably aware that the fuel inside a car engine is ignited by electric sparks. Modern car engines use electronic ignition. An airplane engine uses a more old-fashioned (but more reliable) magneto ignition instead. For redundancy, it contains two such magnetos: the “left” one and the “right” one. When you change the magneto switch on OFF, both magnetos are switched off and the engine will not run. With the magneto switch on L you are using the left magneto. On R you are using the right magneto. On BOTH you use both. In flight you will use BOTH.

Given that you use both magnetos in flight, why have the switch? The reason is that during your pre-flight checks you will verify that each of the magnetos is working correctly. To do this, increase the RPM to about 1500 then switch the magneto switch to L and observe the tachometer. You should observe a slight drop in RPM. If the engine cuts out, the left magneto is broken. If you do not see an RPM drop, then the switch may be faulty, as both magnetos are still switched on. You can then perform the same test on the right magneto. Of course, in the simulator, the magnetos are unlikely to fail!

Should one of the two magnetos fail in flight, the other one will keep the engine running. The failure of one magneto is rare, the failure of both simultaneously is almost unheard of.

You may have typed { to shut the engine down. To start the engine again after doing so, type } three times in order to put the magneto switch on BOTH. Then use the starter motor by pressing the s for a few seconds, till the engine is started.

You can also turn the magneto switch and start the engine by clicking left and right of the switch in normal mouse mod). Type Ctrl-c to see the two click sides highlighted by yellow rectangles.

If you turn the switch to OFF, the engine noise stops. If you quickly turn the switch back to L, the engine starts again as the propeller is still turning. If you wait for the propeller to stop, placing the switch on L, R or BOTH won’t start the engine. (Once the engine is halted, always place the magneto switch to OFF.)

Throttle

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You already know that you increase the engine power by pushing that throttle rod in (Page Up key). You decrease the power by pulling the control out (Page Down key). You can also click left and right of the lever (middle mouse button for quicker moves, Ctrl-c to highlight the left and right halves).

What does “increase the power” actually mean? Does it mean you increase the amount of fuel delivered to the engine? Yes, but this is not enough to fully understand what you are doing. You need to be aware that the engine is also fed with a huge amount of air. The engine’s cylinders burn an mixture of fuel and air. Fuel alone wouldn’t burn. Only a mixture of fuel and air can detonate and move the engine pistons. So when you push the throttle in, you increase both the fuel and the air fed to the engine.

Mixture

The amount of air compared to the amount of fuel is critical. The proportion of the two has to be tuned closely. This is the purpose of the mixture lever. The picture below displays the mixture lever, pulled out far too much.

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When the mixture lever is fully pushed in, you feed the engine with an lots of fuel and little air. This is known as a “rich” mixture. When the lever is pulled out completely, there is an excess of air, known as a “lean” mixture. The correct position to produce maximum power is in between these two extremes, usually quite close to fully pushed in.

When you start the engine and when you take off, you need a fuel-rich mixture. That means the mixture lever should be pushed in. A fuel-rich mixture allows the engine to start easily. It also makes the engine a little more reliable. The drawback is that a part of the fuel is not burned inside the engine. It is simply wasted and pushed out the exhaust. This makes the engine more polluting, it decreases the energy the engine can deliver and it slowly degrades the engine by causing deposits of residues inside the cylinders.

Once in normal flight, you have to pull the mixture lever a little, to get a more optimal mixture. Check this out by doing the following. Start the simulator. Put the parking brakes on with key B (that is Shift-b). Push the throttle in to its maximum. The engine RPM should now be close to the maximum. Slowly pull on the mixture lever (using the mouse in normal pointer mode). You will see the RPM increases a little. You get more power, without increasing the fuel intake. You waste no fuel and it pollutes less. If you continue to pull the mixture lever, the RPM will decrease back away, because now there is too much air. The excess of air slows the explosions down inside the cylinders and decreases the explosion temperature, hence the thermodynamic yield decreases. You have to tune in the optimal mixture. For thermodynamic reasons, the best mixture isn’t exactly at maximum power - it is better for the engine to be running very slight richer or leaner than maximum power. This also avoids the possibility of the fuel detonating explosively damaging the engine. You can find the maximum power point by the fact you get the highest RPM. (Another method is to check the engine exhaust temperature. Roughly, this is the point at which you get the highest temperature.)

The mixture control allows you to burn less fuel for the same speed and distance, and therefore fly farther and pollute less. However, if you mis-manage it, it can cause serious problems. Suppose you go flying at high altitude and pull out the mixture lever accordingly. At high altitude there is less oxygen available so the correct mixture will be quite lean - i.e. with little fuel being used. Then you descend back in order to land. If you forget to push the mixture lever in as you descend, The fuel/air mixture will become far too lean and the engine will simply halt.

When landing, you have to tune back in a mixture that is a little too rich in fuel. This means pushing the mixture lever in. That way the engine becomes a little more reliable and will be better adapted to a decrease in altitude.

I wrote above that placing the magneto on OFF is not the right way to stop the engine. The right method is to pull the mixture lever. First pull the throttle out completely, to get the engine to minimum power and fuel consumption. Then pull the mixture lever, till the engine stops because the mixture contains too much air. This ensures the engine doesn’t get choked by waste fuel residues. Finally, turn the magneto switch to OFF to ensure the engine won’t start again accidentally.

An important warning: you may think the RPM indicator reflects the engine power. Wrong. Two things make the RPM increase: the engine power and the airplane speed. To check this, fly to a given altitude then pull the engine power to minimum. Try out diving to the ground then rising back to altitude. You will see the RPM varies significantly as does your airspeed. It rises while diving and decreases while climbing.

One pitfall of this is when you intend to tune the engine power in for landing. Suppose you’re descending towards the airport, flying fast. You know the ideal RPM for landing is around 1,900 RPM. So you pull the throttle till you get 1,900 RPM. You think you tuned in the appropriate RPM. You think you shouldn’t bother any more about it. But when you level off, the plane’s speed starts to decrease, along with the RPM. A few minutes later, you get the low flight speed you wanted. You don’t see the RPM is now far too slow. You will either lose altitude or stall. Or both. Be cautious with the throttle and with the RPM indicator. Either pull on the throttle more steadily or be mentally prepared to push it back in quickly.

8.7.2 Wings and speed

Say you are flying with full engine power. Dropping the nose a little makes you lose altitude and raising the nose a little makes you gain altitude. You may think this is quite straightforward. The plane travels in the direction it is heading; the direction the propeller is heading. This is not the best way to think about it. This model would be fine for a rocket, but not for an airplane. A rocket is lifted by its engine, while a plane is lifted by its wings. That’s a huge difference.

Get a big rigid square of cardboard, hold it horizontally in your hand with your arm stretched out and make it do fast horizontal movements while rotating your torso. When the cardboard moves flat through the air, it experiences no lift force. If you twist your arm slightly to give the cardboard a slight upward angle, you will feel it tends to lift in the air. There is an upward force acting on the cardboard. That’s the way a wing holds a plane in the air. The wings have a slight upward angle and lift the airplane. The more angle you give the cardboard, the more lift force. (Till you give it too steep an angle. Then you will rather feel a brake force. The cardboard is “stalling” (see below).)

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What matters is the angle the wings travel through the air. This is the angle of attack.

I wrote above that when the wings travel through the air with no angle of attack, they don’t produce lift. This is false. It would be true if the wings were a flat plate like the cardboard. But they aren’t. The wings are a slightly curved airfoil. This makes them create lift even when traveling through the air at no angle of attack. Actually, even with a little negative angle of attack they still create a lift force. At high speed the airplane flies with the wings slightly angled towards the ground!

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The angle at which the wings travel through the air matters. Something else matters too: the speed. Take the cardboard again in your hand. Hold it with a given slight angle and don’t change that angle. Move it at different speeds through the air. The faster you move the cardboard, the more upward force it experiences.

To make things a little more complicated: when rising in the air, the airplane tends to lose speed. When descending, it tends to gain speed.

That’s all a matter of compromises. If you want to fly at a constant altitude and at a given speed, you will have to tune both the engine power and the yoke/elevator (or better: the trim (see below)), till you get what you want. If you want to descend yet keep the same speed, you have to push the yoke a little and decrease the engine power. And so on. You constantly have to tune both the engine power and the yoke. However, during a normal flight you can simplify this by simply choosing a comfortable engine power level then relying on the yoke and trim for altitude.

A very interesting exercise you can perform with the simulator is to fly straight with full engine power. Get maximum speed while keeping in horizontal flight. Then decrease the engine power to minimum. Pull steadily on the yoke to keep the plane at constant altitude. The plane slows down steadily, meanwhile you have pull more and more on the yoke to stay level. Since the speed decreases the lift from the wing will decrease, but you compensate the loss of speed by increasing the wing angle of attack. This proves the plane does not necessarily travel in the direction its nose is heading. In this experiment we make the nose rise in order to stay at constant altitude. Once the plane is flying very slowly, and the nose is very high, you may hear a siren yell. That’s the stall warning (see below). This indicates that the angle of attack is too high for the airfoil to produce lift. The wings are no longer producing lift and the plane quickly loses altitude. The only way to correct this is push the yoke forwards to reduce the angle of attach, making the nose drop, then apply full power to gain speed and finally bring the yoke carefully back to level flight.

Question: is it better to control the airplane’s speed and altitude with the yoke or with the throttle? Answer: it depends on what exactly you intent to do and on the situation you are in. In normal flight, as said above, you tend to set a comfortable engine power level, forget about it and rely on the yoke and trim. During take off and landing the procedures are quite strict about the use of yoke and throttle. You do the opposite: control the speed with the yoke and trim, control the altitude and descent speed with the engine throttle. This will be discussed further below.

8.7.3 The flaps

The flaps are situated at the rear of the wings, either side of the aircraft fuselage.

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You deploy the flaps and retract them back in by using the flaps control lever:

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You can either click on it with the mouse or use the [ and ] keys. Key [ to retract the flaps one step, ] to deploy them one step at a time. Type v to view the plane from the outside and try out [ and ]. (On the schematic instrument panel the flaps lever is located at the lower right.)

In the Cessna 172P. there are four flaps settings:

The flaps are somewhat delicate. Do not deploy the first step of flaps above 110 knots. Do not deploy the second or third stage of flaps above 85 knots.

The flaps create large amounts of drag on the aircraft and brake the plane at high speed. This is one more reason not to forget to pull the flaps back in once you fly above 85 or 110 knots.

To check the flaps position visually, either use the mouse view mode to look at the back of the wing, or type Shift-right arrow to shift the view to the right and then quickly Shift-up arrow to get back to front view.

Flaps increase wing lift by altering the shape of the airfoil. The wing lifts more at a given speed with the first stage of flaps set. Hence you will get in the air a little sooner during take off. It also has the effect to make the plane fly with a lower nose attitude. This is useful as it provides a better view of the runway when taking off or landing.

The flaps also increase drag on the aircraft. The second and third stage of flaps produce much more drag than lift, so they are used to brake the plane. This is particularly useful when landing, because the airplane glides very well. If you cut down the engine power completely, the plane will descend, yet but too slowly. You need to deploy two or three flaps steps in order to brake and really descend towards the ground.

The fact that the flaps brake during landing makes you need more engine power during the landing. This can seem odd. Why not simply throttle the engine down to minimum and use less flaps steps? The answer is that it is better to have a strongly braking plane and lots of engine power, as the plane reacts faster to your commands. Should the engine fail, then just retract flaps as needed and glide to the runway.

What can you do if you have full flaps extended and need to increase your rate of descent further? Slowly push the rudder pedals on one side. This will make the plane present its flank to the air stream and brake. Compensate the turning by using the ailerons (yoke). This is known as side-slipping, and is a very effective way to lose height progressively as it is easy to stop at any point.

8.7.4 The stall

An aircraft relies on the smooth flow of air over the surface of the wing to produce lift. However, if the wing is at too high an angle of attack, this flow is broken, and the wing no-longer produces lift. With no lift, the aircraft cannot fly, and quickly drops back to earth. This is known as a stall.

A stall is an emergency situation, whatever the While it can happen at any speed, it commonly occurs in slow flight. A given aircraft has a specific stall speed, at which no angle of attack can produce enough lift. You should always keep your aircraft well above the stall speed. To help, aircraft are equipped with stall sirens that sound when the angle of attack is approached.

If you encounter a stall, the remedial action is to immediately drop the nose, and apply full power, bringing the nose level when flying speed has been attained again. However, doing so will cause the aircraft to lose altitude, which you may not have to spare when landing or taking off!

A spin occurs when one wing stalls before the other, which can occur in a steep turn at low speed. As one wing is still flying, the aircraft turns around the stalled wing, spinning tighter and tighter. To get out of a spin, you need to apply rudder to straighten out the spin into a normal stall, then recover as above.

Aircraft like the Cessna 172 and Piper Cub, have benign stalls, and are unlikely to enter a spin. High performance jets, such as the F16 have much more agressive stalls, and can easily enter a spin.

To practise this in the simulator, do the following:

You can also experiment with stalls with different flap settings, and high speed stalls by making abrupt attitude changes.

Experiment with different aircraft. Compared with the Cessna 172 the Cessna Citation jet, stalls much more agressively and with little warning..

8.7.5 The trim

The trim is the dark big vertical wheel with gray dots located at the middle below the instrument panel:

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On FlightGear, the keys Home and End adjust the trim. Home rolls the wheel upwards while the End rolls the wheel downwards. You can also click on the upper or lower half of the trim wheel.

In first approximation, the trim does the same as the yoke: it acts on the elevator. Turning the trim wheel downwards is the same as pulling on the yoke. Yet there is a key difference between the trim and the yoke. The trim remains in position after you make a change, while the yoke only continues to affect the elevator while you apply pressure and returns the elevator to neutral when you release it.

During cruise flight, the required elevator position to keep the aircraft at constand altitude will not be completely neutral - it will vary depending on the air outside the aircraft, the current fuel level, and the payload. Obviously, holding the yoke continually to retain a constant attitude would quickly become tiring. By using the trim to “trim out” the elevator force required for cruise flight, the yoke can be kept neutral.

During take off the trim should be neutral. Otherwise you may find that it either refuses to take-off with the normal level of yoke control, or takes off too quickly.

During landing, try to get the yoke/mouse/elevator towards neutral position by tuning the trim. This makes making small adjustments to your attitude and position easier. On the Cessna 172p this means trim on neutral. On the Cherokee Warrior II this means the trim a little “pulled”.

The trim wheel movement is much slower than the yoke, allowing for delicate changes in trim. Be patient.

8.7.6 What direction am I flying?

Knowing the direction you are going is obviously a good idea. There are three basic ways to determine the direction you are flying:

8.7.7 A look around the panel

Finally, let’s have a look at the instrument panel, combining the instruments described above with some new ones.

The six-pack

Let us start with the most important instruments any simulator pilot must know, these are known as the “holy six” or the “six-pack” . In the center of the instrument panel (Fig. 5), in the upper row, you will find the artificial horizon (attitude indicator) displaying pitch and bank of your plane. It has pitch marks as well as bank marks at 10, 20, 30, 60, and 90 degrees.

Left of the artificial horizon, you’ll see the airspeed indicator. Not only does it provide a speed indication in knots but also several arcs showing characteristic velocity rages you have to consider. At first, there is a green arc indicating the normal operating range of speed with the flaps fully retracted. The white arc indicates the range of speed with flaps in action. The yellow arc shows a range which should only be used in smooth air. The upper end of it has a red radial indicating the speed you must never exceeded, unless you want to break up the plane in mid-flights…

Below the airspeed indicator you can find the turn indicator. The airplane in the middle indicates the roll of your plane. If the left or right wing of the plane is aligned with one of the marks, this would indicate a standard turn, i.e. a turn of 360 degrees in exactly two minutes.

Below the plane, still in the turn indicator, is the inclinometer. It indicates whether the rudder and ailerons are co-ordinated. During turns, you always have to operate aileron and rudder in such a way that the ball in the tube remains centered; otherwise the plane is skidding. A simple rule says: “Step on the ball”, i.e. step onto the left rudder pedal when the ball is on the left-hand side.

If you don’t have pedals or lack the experience to handle the proper ratio between aileron/rudder automatically, you can start FlightGear with the option --enable-auto-coordination.

To the right-hand side of the artificial horizon you will find the altimeter showing the height above sea level (not ground!) in hundreds of feet. Below the altimeter is the vertical speed indicator indicating the rate of climbing or sinking of your plane in hundreds of feet per minute. While you may find it more convenient to use than the altimeter in certain cases, keep in mind that its display usually has a certain time-lag.

Further below the vertical speed indicator is the propellor tachometer, or RPM (rotations per minute) indicator, which displays the rotations per minute in hundreds. The green arc marks the optimum region for cruise flight.

The group of the main instruments further includes the gyro compass being situated below the artificial horizon. Besides this one, there is a magnetic compass sitting on top of the panel.

Four of these gauges being arranged in the from of a “T” are of special importance: The air speed indicator, the artificial horizon, the altimeter, and the compass should be scanned regularly during flight.

Supplementary Instruments

Beside the six-pack, there are several supplementary instruments. To the very left you will find the clock, obviously being an important tool for instance for determining turn rates. Below the clock there are several smaller gauges displaying the technical state of your engine. Certainly the most important of them is the fuel indicator - as any pilot should know.

The ignition switch is situated in the lower left corner of the panel (cf. Fig. 4). It has five positions: “OFF”, “L”, “R”, “BOTH”, and “START”. The first one is obvious. “L” and “R” do not refer to two engines (as the Cessna 172 only has one) but the two magnetos, providing redundancy in the case of a failure.. The two switch positions can be used for test puposes during preflight. During normal flight the switch should point on “BOTH”. The extreme right position is for using a battery-powered starter (operated with the “s” key).

The handle below the yoke is the parking brake. In the vertical position, the parking brake is ON. The parking brake is operated with the “B” key.

Radios

The right hand side of the panel is occupied by the radio stack. Here you find two VOR receivers (NAV), an NDB receiver (ADF) and two communication radios (COMM1/2) as well as the autopilot.

The communication radio is used for communication with air traffic facilities; it is just a usual radio transceiver working in a special frequency range. The frequency is displayed in the LEDs. Usually there are two COM transceivers; this way you can dial in the frequency of the next controller to contact while still being in contact with the previous one.

The COM radio can be used to listen to the current weather conditions at an airport, known as ATIS. To do this, simply dial in the ATIS frequency of the relevant airport. You can find this by selecting ATC/AI->Frequencies from the menu, and selecting the 4-letter ICAO code of a nearby airport.

Each COM radio has two frequencies configured - an ‘active’ frequency which the pilot is transmitting and receiving on, and a ‘standby’ frequency which may be changed. In this way, you can continue to listen on one frequency while tuning another one.

You can change the radio frequency using the mouse. For this purpose, click left/right to the circular knob below the corresponding number. The corresponding switch left to this knob can be used for toggling between the active/standby frequency.

Use of the autopilot and radio navigation equipement is covered in later tutorials. For the moment you can ignore these radio instruments as long as you are strictly flying according to VFR (visual flight rules).

8.8 Let’s Fly

By now you will be able to keep on runway while taking off by using the rudder and you’re able to fly straight, descend, climb and make gentle turns. This section will describe a slightly more realistic approach to taking off and landing, and introduce some of the more subtle concepts you should be aware of.

8.8.1 A realistic take off

The following general rules apply during a normal take-off:

So, you need to take off and rise in the air at a steady speed of around 75 knots. However, when you raise the nose slightly at 40 knots, the aircraft will probably take-off at around 55 knots. To accelerate quickly to 75 knots, lower the nose slightly immediately on take-off, then raise it once 75 knots has been achieved. You are using the yoke to control the speed of the aircraft.

Putting this all together with what you have learned previously, a normal take-off using the mouse will consist of the following:

  1. Adjust the altimeter to the correct altitude, based on the airport altitude. For reference, KSFO is at sea level - 0ft.
  2. Check aileron and elevator are neutral by observing the yoke position.
  3. Change the mouse to control mode by pressing Tab.
  4. Hold the left mouse button down to control the rudder.
  5. Apply full power (hold PgUp until the throttle is fully in).
  6. As the aircraft accelerates down the runway, keep it in the center by making small adjustments using the mouse.
  7. As 40kts is reached, release the left mouse button, and pull back slightly to raise the nose-wheel. You are now controlling the yoke with the mouse.
  8. The aircraft will fly off the runway at approximately 55 knots.
  9. Lower the nose slightly to accelerate to 70 knots
  10. Keep alignment with the runway.
  11. Use the yoke to keep the ASI at 70 knots as you climb. If the airspeed is dropping, lower the nose. If the airspeed is increasing, raise the nose slightly.
  12. Once you reach 500 feet, turn to your required heading, staying away from buildings until you are over 1,000ft.

8.8.2 Landing

The rules for landing are almost identical to that of take-off, but in reverse order:

Landings are much easier if you have an aiming point picked out on the runway. By observing the aiming point, you can easily tell if you are descending too fast or too slowly. If the aiming point appears to move upwards, you are descending too fast,

Obviously, you need to be lined up with the runway.That means your flight direction has to match the middle line of the runway (drawing (a) below). In order to arrive at this, don’t aim at the start of the runway (b). Rather aim at a fictitious point well in front of the runway (c). And begin to turn gently towards the runway well before you reach that fictitious point (d). Note the turns and bankings you make for these flight corrections are often very soft. You wouldn’t even notice them on the turn coordinator. This is one example where you better rely on the outside horizon line than on the inside flight instruments.

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A straight in landing using the mouse would consist of the following:

  1. 1,500ft above the airport, and a couple of miles out, an in-line with the runway, reduce power to approximately 1500rpm. This will slow you down somewhat and start a gradual descent.
  2. Once below 115 knots, apply one step of flaps (]). This will increase lift, but also slow you down.
  3. Re-trim the aircraft so you continue to descend.
  4. At around 1,000 feet, apply another step of flaps (]). This increase drag significantly, but also improve the view over the nose.
  5. Tune the speed using the elevator and trim: push the yoke if you are flying below 70 knots, pull the yoke if you are flying above 70 knots. If using a joystick, use the trim to relieve any pressure on the elevator.
  6. Tune the altitude using the engine throttle. Add power if you are descending too fast, reduce power if you are too high. It is much easier to work out if you are too high or too low by observing the numbers on the runway. If they are moving up the screen, you are descending too fast - increase power. If they are moving down, you are too high and need to reduce power.
  7. Make minor adjustments to heading to keep aligned with the runway.
  8. at about 500ft, apply the final step of flaps. (]). This increase drag significantly, so be prepared to increase power to keep your descent constant.
  9. When you are just above the runway, reduce power to idle, and use the yoke to gently pull back the aircraft to horizontal. This is the “round-out” and should result in the aircraft flying level with the runway a couple of feet above the surface. Performing the round-out at the correct height is a difficult task to master. To make it easier, observe the horizon rather than getting fixated on the aiming point.
  10. Keep the wings level using small inputs with the yoke. We want both wheels to touch down at the same time.
  11. Continue pulling back on the yoke. The main wheels should touch down at about 55 knots. This is the “flare”.
  12. As you touch down, be ready to use the rudder to keep the aircraft straight (keypad 0 and keypad Enter)
  13. Once you are below 40 knots, lower the nose-wheel to the ground.
  14. Hold down the left mouse button to control the nosewheel/rudder using the mouse.
  15. Once below 30 knots, use the brakes b to slow the aircraft further.

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Once the plane is halted or at very low speed, you can release the b key and add a little engine power to taxi to the parking or hangar.

8.8.3 Engine Shutdown

To shut the engine down:

8.8.4 Aborted Landing

You must be mentally prepared to abort landing any time the landing doesn’t look good, or due to external factors such as:

To abort the landing, apply full power (hold PgUp), raise the nose to climb, and once you are climbing, retract the flaps (key[).

Landing is much harder than taking off. Landing on a large runway, such as KSFO (San Francisco, the default) is much easier than smaller runways such as KHAF (Half Moon Bay, about 10 miles to the south west of KSFO).

To practise landings, use the command line below in a terminal window to start the simulator in flight and heading for the runway. The airplane is placed 5 miles ahead of the runway, at an altitude of 1500 feet and a speed of about 120 knots.

fgfs --offset-distance=5 --altitude=1500 --vc=120 --timeofday=noon

Approaching to land at 65 knots instead of 70 knots allows to use a much shorter runway length. However, this requires better control, particularly as it is much closer to the stall speed. It is quite different from landing at 70 knots.

8.9 Dealing with the Wind

Consider a hot air balloon. Think of it as being in the middle of a gigantic cube of air. The cube of air may move at high speed compared to the ground, but the balloon itself is completely static in the middle of the cube. Whatever the wind speed, persons aboard a hot air balloon experience not a breath of wind.

In the same way, an aircraft flies in the middle of a gigantic cube of air and flies relative to that air mass. The motion of the cube of air relative to the ground has no effect on the aircraft.

You, the pilot, on the contrary, are interested in the speed of the surrounding air compared to the ground. It can make you drift to the left or to the right. It can make you arrive at your destination much later or much sooner than planed.

When the wind blows in the same direction as you fly, the speed of the wind adds itself to the airspeed of the plane. Hence you move faster compared to the ground. You will arrive earlier at your destination.

When the wind blows in the opposite direction (towards the nose of the plane), the speed of the wind subtracts itself from the airspeed of the plane. Hence you move slower compared to the ground. You will arrive later at your destination and have more time to enjoy the landscape.

The two cases above are quite simple. More complex is when the wind blows towards the side of the airplane. Consider the diagram below.

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How much to the left or to the right of the object must you head? At what angle? Serious pilots use geometry and trigonometric computations to calculate the correct angle. You need no computations at all to fly roughly straight. The trick is to choose an aiming point in the direction you wish to fly, then observe how it moves. You will become aware if you are drifting leftwards or rightwards. Then let your instinct slowly head the plane to the right or to the left to compensate the obvious drift. To begin with, you may need to think about what you are doing. Very soon this will become automatic, just like when you learned to fly straight. You will no more keep the plane headed towards the object. You will rather keep it flying towards the object.

The faster the flight airspeed compared to the wind speed, the less correction you will need.

8.9.1 Crosswind Take Off

Taking off when the wind is coming from the side is tricky. Airport designers avoid this by placing runways so that they face into the prevailing wind. Often airports have multiple runways, placed such that there will be a runway facing straight into wind as much of the time as possible.

Taking off with a wind blowing straight towards the nose of the aircraft makes life easier as it is the speed of the wing relative to the air that causes lift. When there is no wind, the aircraft must accelerate to 55 knots to take off. However, if there is a 10 knot head-wind, the aircraft has an airspeed of 10 knots standing still and only has to accelerate to 45 knots relative to the ground to take off. This shortens take-off distances.

Just as a headwind shortens take-off, a tail-wind increases take-off length. Anything more than a knot or two makes a huge difference to take-off distance. As (most) runways can be flown from either end, you can easily take off from the other end of the runway and benefit from the headwing.

The main way to know the wind direction and speed is to go to the control tower or ask the control tower by radio. A necessary and complementary tool are the windsocks at both ends of the runway. They show the wind direction and speed. The longer and the stiffer the windsock, the more wind there is. The windsock on the picture below shows an airspeed of 5 knots:

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Unfortunately, sometimes there isn’t a runway facing the wind, and you have to take off when the wind is blowing from the side.

The technique is as for a normal take-off with two changes:

8.9.2 Crosswind Landing

Landing in a crosswind is very similar to the take-off:

The technique described here is the slip landing. Another crosswind landing technique is the crab landing.

8.9.3 Taxiing in the Wind

Under 10 knots wind the Cessna 172p seems not to need particular precautions when taxiing. Yet any sudden increase in wind speed can tilt it and tumble it over. So best apply the recommendations whenever there is wind.

To train taxiing on the ground when there is wind, configure the simulator for a strong wind, like 20 knots. Such a wind can tilt the plane and blow it away tumbling any moment. One single error during taxiing and the plane is lost.

Main rule is you must push the yoke towards the wind. This deserves some physical explanation:

If you want to move towards the wind, you will need more engine power. When the wind blows from the rear you may need no engine power at all. Always keep the engine power to the minimum needed.

Especially when turning, move very slowly. Make little changes at a time. Take your time and closely survey the yoke angle. Constantly keep it pushed towards the wind. Constantly try to reduce the engine power. Keep in mind using the brakes too firmly may shortly tilt the plane at an angle that allows the wind to tilt it and blow it away.

8.10 The autopilot

An autopilot is not an “intelligent” pilot. It just takes over simple tasks for the pilot. You still are the pilot aboard and have to keep aware of everything. Be prepared to shut the autopilot down as they often go wrong, both in real life, and in the simulator.

The autopilot is mounted to the right of the yoke:

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Switch it on by pressing the AP button. The autopilot then controls the roll of the aircraft. It keeps the wings level with the horizon. This is displayed in the picture below by the “ROL” marking. To switch the autopilot off press AP again.

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If you press the HDG button the autopilot will try to keep the plane flying towards the direction tuned on the directional gyro by the red marking (see section 8.7.6). “HDG” stands for “heading”. Press again on the HDG button to get back to roll control mode (or AP to switch the autopilot off).

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The buttons ALT, UP and DN are used to tell the autopilot either to control the vertical speed VS or the altitude ALT. For more advanced use of the autopilot, see the reference document for the autopilot modelled in the Cessna 172: Bendix King website

8.11 What Next?

This tutorial has introduced you to the basics fo flight in the Cessna 172. From here you can explore the many features that FlightGear has to offer.

Once you have mastered the content of this tutorial, you may want to look at the other tutorials in this Manual, covering flying to other airports, flying using instruments when clouds obscure the ground, and flying helicopters.

This tutorial has skipped over a number of topics that a real-life pilot would have to consider:

This tutorial has also not covered features of more advanced aircraft, including:

8.12 Thanks

I wish to thank:

8.13 Flying Other Aircraft

I cross-checked all the data about the Cessna 172p, a pilot friend verified I did not write too much rubbish and I made numerous virtual test flights. This section contains less reliable data about other airplanes based on my experience in the simulator. You may find it useful as an introduction to those airplanes but bear in mind my only goal was to make flights that seem OK and acquire basic knowledge.

8.13.1 How to land the Cherokee Warrior II

The Cherokee Warrior II has some advantages upon the Cessna 172p. Thanks to its low wings it is far less sensitive to crosswind. Fully extended flaps are provide more braking and allow it to land on a much shorter distance.

Take off is the same as for the Cessna 172p in FlightGear. In real life their take off checklists are not exactly the same.

You have to get used to some minor differences of the Cherokee Warrior II for the landing:

In real life, an advantage of the Cessna 172p upon the Cherokee Warrior II is the fuel reservoirs of the Cessna are located in the wings close above the center of the plane and higher than the engine. What’s more an automatic system switches between the reservoirs. That means you almost don’t have to bother for the way the fuel gets to the engine in flight. On the contrary, on the Cherokee Warrior II the reservoirs are located separately, on both wings and lower than the engine. That means you have to constantly switch between the two reservoirs in flight. Should one reservoir become much lighter than the other, this would destabilize the airplane. The fact the reservoirs are lower than the engine means you have to control the fuel pumps and the backup fuel pumps.

Some links:

8.13.2 How to take off and land the Piper J3 Cub

The Piper J3 Cub is a very different airplane from the Cessna 172p and the Cherokee Warrior II. The Cessna 172p and the Cherokee Warrior II are nose-wheel airplanes, while the Piper J3 Cub is a tail wheel airplane. Take off and landing with tail wheel airplanes is more difficult. You have to tightly use the rudder pedals when rolling over the runway. The yoke often needs to be pulled backwards to the maximum. The Piper J3 Cub is a good introduction to tail-wheel aircraft and it is quite easy to take off and land provided you follow an appropriate procedure. Stall speed seems to be a little below 40 mph (the airspeed indicator is in mph) (about 27 knots). Take-off is below 50 mph.

My take off procedure for the Piper Cub is to fully pull the yoke backwards then throttle the engine to maximum. Once the front wheels clearly rises from the ground, gently push the yoke back to neutral, towards a normal flight close above the runway. Let the plane accelerate to 50 mph. Then pull the yoke to keep a little more than 50 mph while rising in the air.

The landing procedure is quite different to that of 172, as the aircraft is very light, and has no flaps.

  1. Fly at say 500 feet constant altitude and "exactly" 52 mph speed towards the runway. Let the engine cover eat up the runway start. The engine cover will hide the runway completely. To see where the runway is, push the yoke/mouse very shortly then stabilize again in normal flight.
  2. Once the runway start matches with the set of instruments (if you could see through the instrument panel), reduce the throttle to a near minimum and begin the dive towards the runway start. Keep 52 mph using the yoke. Add some throttle if you are going to miss the runway edge. (Keep in mind just a little wind is enough to change things a lot for the Piper J3 Cub).
  3. Make the rounding and pull the throttle to minimum. Do not pull steadily on the yoke. Instead let the wheels roll on the runway immediately.
  4. Once the wheels roll on the runway, push firmly on the yoke, to its maximum. This rises the tail in the air. You would think the propeller will hit the runway or the airplane will tilt over and be damaged. But everything’s fine. The wings are at a strong negative angle and this brakes the plane. (Don’t push the yoke this way on other airplanes, even if their shape seems close to that of the Piper J3 Cub. Most of them will tumble forwards.)
  5. The yoke being pushed in to its maximum, push the left mouse button and keep it pushed to go in rudder control mode. Keep the plane more or less centered on the runway. This is quite uneasy. One tip is to stop aiming the rudder to say the left already when the plane just starts to turn to the left.
  6. Once the speed is really low (and the rudder control stabilized), you will see the tail begins to sink to the ground. Release the left mouse button to go back to yoke control. Pull the yoke backwards completely, to the other extreme. The tail now touches the ground and the nose is high up. Now you can use the wheel brakes (b). (If you use the brakes too early, the plane nose will hit the ground.)

The take off procedure mentioned above is symmetrical to the first landing procedure. There exists a second take off procedure, symmetrical to the second landing procedure. Yet I don’t succeed it properly so I won’t write about it.

8.13.3 How to take off and land a jet

Take off on a jet is easy but you must have fast reflexes. My favorite jet on FlightGear is the A-4 Skyhawk. You get it with the –aircraft=a4-uiuc parameter on Linux, provided it is installed.

This is the “calm” procedure to take off:

The “nervous” take off procedure is the same but you push in full engine power. The plane takes off quickly and you need to settle a very steep climb angle to keep 200 knots. Best retract the landing gear immediately.

You don’t land a jet the same way you land a little propeller airplane. My way to land the A-4, inspired by some texts I found on the Web, is this:

The HUD in a real jet contains a symbol to show towards what the airplane is moving. It is shown in the picture below. When you are flying at constant altitude, that symbol is on the ideal horizon line. Once you dive towards the runway start, you simply have to place that symbol on the runway start. This is quite an easy and precise way to aim at the runway start. (The diamond in the center of the FlightGear HUD sometimes can help but it does not have the same purpose. It shows towards what the airplane nose is pointing. For example is you descent towards the ground at low speed, the symbol would be somewhere on the ground while the FlightGear diamond will be up in the sky.) (By the way, the HUD on the virtual B-52 on FlightGear has that symbol. It is great to use while landing.)

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Also, a real HUD shows a dotted line at -2,5˚ , to help find the correct descent path. Simply keep that dotted line on the runway thresh-hold.

In additional to airspeed, military fast jet pilots rely on using the correct angle of attack during approach. The Angle Of Attack (AoA) is the angle at which the wings are pitched against the relative airflow. The advantage of keeping to an optimal AoA is that the optimal AoA for landing does not depend on the plane load, while the optimal airspeed speed does. By ensuring that the AoA is correct for every landing, you will land at the correct speed, whatever the plane load.

The Angle of Attack is displayed within the HUD, and/or as a set of three lights shown below. When the upper is lit, your angle of attack (AoA) is too high and you need to pitch down. When the lower is lit, your AoA is too low and you need to pitch up. The center indicates your the AoA is OK. Obviously, as you pitch up or down your airspeed and descent rate will change, so you will need to change your throttle setting appropriately.

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The Cessna 172 and the A-4 Skyhawk are two extremes. Most other airplanes are in-between these two extremes. If you trained them both (and one or two tail wheel airplanes), you should be able to find out how to take off and land most other airplanes.

160 knots seems an appropriate landing speed for the F-16 Falcon. Also you need to throttle down the engine to minimum just before the plane should touch the runway. Otherwise it will hover over the runway. Don’t bother for the flaps. It seems they are deployed automatically with the landing gear. (Read the section 8.7.4 about the stall).

140 up to 150 knots and all 8 flaps steps deployed seem appropriate to land the virtual Boeing 737. But don’t trust me especially on that one. I just made a few experiments and didn’t search for serious data. The landing speed varies a lot depending on the plane load, I suppose 140 knots is for a plane with no load. The Boeing 737 seems to like a gentle rounding before the wheels touch the runway. Start the rounding early.

In the take off procedure for the Cessna 172 and the A-4 Skyhawk I recommend you pull the yoke/mouse/elevator to 1 2 the total way, from the start on. This seems to be a bad practice on the Pilatus PC-7. Keep the elevator neutral. Let the plane accelerate and wait till the speed gets over 100 knots. Then pull calmly on the yoke. During landing, deploy full flaps once you start plunging to the runway but don’t decrease the engine throttle. Decrease it only when the hovering above the runway starts. 100 knots seems a good landing speed.

For the Cessna 310 too you better leave the elevator neutral during the acceleration on the runway. The plane will raise its nose by its own provided you deployed one flaps step. (If you keep the yoke pulled from the start on, the nose will rise sooner and you will get yawful yaw problems.)

(Some virtual airplanes, like some big airliners or fast aircraft, need faster physical computations. Then add the –model-hz=480 parameter to the command line. If the plane is difficult to control during landings, try this.)

The angle at which you land a Cessna 172p is far steeper than the narrow 2,5˚ for a jet. Nevertheless you are allowed to land the Cessna at a narrow angle too. (Provided the terrain around the runway allows for this, of course.) If you have passengers who have ears problems with the variation of air pressure…

8.13.4 How to take off and land the P-51D Mustang

Should you ever get a chance to pilot a P-51 Mustang, just say no. It is quite dangerous to take off and land. That’s the kind of airplane you fly only when your country is in danger. You need a lot of training. Yet once in the air the P-51 Mustang seems no more dangerous to its pilot than other common military airplanes. It is quite easy to pilot.

At low and medium altitude the P-51 wasn’t better than the Spitfire and the Messerschmitts. The big difference was at high altitude. The P-51 kept efficient and maneuverable while enemy fighters were just capable to hang in the air. This was an advantage at medium altitude too because the P-51 was able to plunge towards enemy airplanes from high altitude. Another key difference was the P-51 is very streamlined. Hence it was capable to fly much further than the Spitfire. These two differences let the P-51 Mustang fulfill its purpose: escort Allied bombers all the way to their targets in Germany. This allowed the bombings to be much more efficient and contributed to the defeat of the Nazis.

To get the P-51D Mustang on Linux use the –aircraft=p51d command line parameter.

To take off the P-51D Mustang in FlightGear, deploy one flaps step, pull and keep the yoke completely backwards, push the engine throttle to maximum and keep the left mouse button pressed to control the rudder and keep on the runway. Once you reach exactly 100 mph, suddenly push the rudder 1/3 of its total way to the right. Immediately release the left mouse button and push the yoke to rise the tail (don’t push it too much, as the sooner the wheels leave the ground the better). From now on, keep the left mouse button released. Only make very short adjustments to the rudder. Let the plane rise from the runway and get to altitude at a speed of say 150 mph. Don’t forget to retract the landing gear and the flaps.

Don’t make too steep turns. You would loose control on the plane and crash.

To land, deploy full flaps and lower the landing gear from the start on. 130 mph speed seems fine, up to 140 mph. Make an approach from 1,000 feet altitude and a dive at a low angle, like for a jet. Once over the runway, shut the engine down completely (key{). Don’t hover over the runway. Get the wheels rolling soon (like for a jet). Hold the left mouse button down to steer the plane using the rudder. Once the tail sinks in, briskly pull the yoke (left mouse button shortly released) to force the tail on the runway. Go on steering the plane using the rudder. Now the tail is firmly on the ground, use the brakes if you want.

8.13.5 How to take off and land the B-52 Stratofortress

The B-52F bomber implemented in FlightGearis a success. It is one of my favorite airplanes. I’m sorry it was conceived to terrify me. One single B-52 bomber can wipe out every main town of my country and rise a nightmare of sicknesses and children malformation for centuries. All B-52 bombers united can wipe out mankind and almost every kinds of plants and animals on Earth.

The differences between the virtual B-52F bomber and the Cessna 172p are these:

This is my procedure to take off the virtual B-52F:

To land, the B-52F’s HUD offers that great airplane-shaped symbol I talked about in the section about jets. So you just have to put that symbol on the airplane threshold (a few pixels further seems optimal) and keep the runway start 2,5˚ below the ideal horizon line. 130 up to 140 knots seems a good landing speed. (Instead of the speed you can make use of the AOA indicator displayed on the schematic instrument panel (P). ). Simply keep the AOA at 3˚ . I must confess I prefer to tune the speed rather than the AOA.) If the plane gets to the runway at 130 up to 140 knots, simply “let it smash” on the runway. Otherwise, if the speed is higher, make a rounding and a short hover. The brakes seem to be very effective b). They allow to stop the B-52F on roughly the same short runway length as the Cessna 172p.

Replays of the flights are a delight. They allow to check the plane body left the runway and landed back parallel with it. One of the points of view is situated inside the B-52F rear turret, which allows you to be your own passenger and to compare what you see with what you experienced as a passenger in airliners. The key K allows to visualize the airplane trajectory.

To cause an accident with the B-52 do this:

Chapter 9
A Cross Country Flight Tutorial

9.1 Introduction


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Figure 9.1: Flying over the San Antonio Dam to Livermore


This tutorial simulates a cross-country flight from Reid-Hillview (KRHV) to Livermore (KLVK) under Visual Flight Rules (VFR). Both airports are included in the standard FlightGear package, so no additional scenery is required.

I’ll assume that you are happy taking off, climbing, turning, descending and landing in FlightGear. If not, have alook at the tutorials listed above. This tutorial is designed to follow on from them and provide information on some of the slightly more complicated flight systems and procedures.

9.1.1 Disclaimer and Thanks

A quick disclaimer. I fly microlights rather than Cessnas in real life. Most of this information has been gleaned from various non-authoritive sources. If you find an error or misunderstanding, please let me know. Mail me at stuart_d_buchanan -at- yahoo.co.uk.

I’d like to thank the following people for helping make this tutorial accurate and readable: Benno Schulenberg, Sid Boyce, Vassilii Khachaturov, James Briggs.

9.2 Flight Planning

Before we begin, we need to plan our flight. Otherwise we’ll be taking off not knowing whether to turn left or right.

First, have a look at the Sectional for the area. This is a map for flying showing airports, navigational aids, and obstructions. There are two scales of sectionals for VFR flight - the 1:500,000 sectionals themselves, and a number of 1:250,000 VFR Terminal Area Charts which cover particularly busy areas.

They are available from pilot shops, or on the web from various sources. You can access a Google-map style interface here:

http://www.runwayfinder.com/

Simple search for Reid-Hillview. An extract from the chart is shown in Figure 9.2.


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Figure 9.2: Sectional extract showing Reid-Hillview and Livermore airports


If you want a map of the entire area showing exactly where the plane is, you can use Atlas. This is a moving-map program that connects to FlightGear. See Section 6.3 for details.

So, how are we going to fly from Reid-Hillview to Livermore?

We’ll be taking off from runway 31R at KRHV. KRHV is the ICAO code for Reid-Hillview airport, and is shown in the FlightGear wizard. (It is marked on the sectional as RHV for historic reasons. To get the ICAO code, simply prefix a ‘K’.)

The 31 indicates that the magnetic heading of the runway is around 310 degrees, and the R indicates that it’s the runway on the right. As can be seen from the sectional, there are two parallel runways at KRHV. This is to handle the large amount of traffic that uses the airport. Each of the runways can be used in either direction. Runway 31 can be used from the other end as runway 13. So, the runways available are 13R, 13L, 31R, 31L. Taking off and landing is easier done into the wind, so when the wind is coming from the North West, runways 31L and 31L will be in use. The name of the runway is written in large letters at the beginning and is easily seen from the air.

Once we take off we’ll head at 350 degrees magnetic towards Livermore (KLVK). We’ll fly at about 3,500ft about sea-level. This puts us at least 500ft above any terrain or obstructions like radio masts on the way.

We’ll fly over the Calaveras Reservoir then the San Antonio Reservoir. These are both large bodies of water and we can use them as navigation aids to ensure we stay on the right track.

Once we get about 10 miles out of Livermore (above the San Antonia Reservoir), we’ll contact the Livermore Air Traffic Control (ATC) to find out where we should land. We’ll then join the circuit and land.

9.3 Getting Up

OK, we know where we’re going and how we’ll get there. Time to get started.

Start FlightGear using the Wizard (or command-line if you prefer). We want to use a C172P and take off from runway 31R at Reid-Hillview of Santa Clara County (KRHV). Dawn is a nice time to fly in California.

If you want, you can fly in the current weather at KRHV by clicking the Advanced button on the final screen of the Wizard, selecting Weather from the left-hand pane, selecting ‘Fetch real weather’ and clicking OK.


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Figure 9.3: On the runway at KRHV


9.3.1 Pre-Flight

Before we take off, we need to pre-flight the aircraft. In the real world, this consists of walking around the aircraft to check nothing has fallen off, and checking we have enough fuel.

In our case, we’ll take the opportunity to check the weather, set our altimeter and pre-set things that are easier to do when you’re not flying.

The weather is obviously important when flying. We need to know if there is any sort of cross-wind that might affect take-off, at what altitude any clouds are (this is a VFR flight - so we need to stay well away from clouds at all times), and any wind that might blow us off course.

We also need to calibrate our altimeter. Altimeters calculate the current alititude indirectly by measuring air pressure, which decreases as you ascend. However, weather systems can affect the air pressure and lead to incorrect altimeter readings, which can be deadly if flying in mountains.

9.3.2 ATIS

Conveniently, airports broadcast the current sea-level pressure along with useful weather and airport information over the ATIS. This is a recorded message that is broadcast over the radio. However, to listen to it, we need to tune the radio to the correct frequency.

The ATIS frequency is displayed on the sectional (look for ‘ATIS’ near the airport), but is also available from within FlightGear. To find out the frequencies for an airport (including the tower, ground and approach if appropriate), use the ATC/AI menu and select Frequencies. Then enter the ICAO code (KRHV) into the dialog box. The various frequencies associated with the airport are then displayed. Duplicates indicate that the airport uses multiple frequencies for that task, and you may use either.

Either way, the ATIS frequency for Reid-Hillview is 125.2MHz.

9.3.3 Radios

We now need to tune the radio. The radio is located in the Radio Stack to the right of the main instruments. There are actually two independent radio systems, 1 and 2. Each radio is split in two, with a communications (COMM) radio on the left, and a navigation (NAV) radio on the right. We want to tune COMM1 to the ATIS frequency.


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Figure 9.4: The C172 communications stack with COMM1 highlighted


The radio has two frequencies, the active frequency, which is currently in use, and the standby frequency, which we tune to the frequency we wish to use next. The active frequency is shown on the left 5 digits, while the standby frequency is shown on the right. We change the standby frequency, then swap the two over, so the standby becomes active and the active standby. This way, we don’t lose radio contact while tuning the radio.


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Figure 9.5: COMM1 adjustment knob


To change the frequency, click on the grey knob below the standby frequency (highlighted in Figure 9.5), just to the right of the ‘STBY’. Using the left mouse button changes the number after the decimal place, using the middle button changes the numbers before the decimal place. Click on the right side of the button to change the frequency up, and the left of the button to change the frequency down. Most of the FlightGear cockpit controls work this way. If you are having difficulty clicking on the correct place, press Ctrl-C to highlight the hot-spots for clicking.


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Figure 9.6: COMM1 switch


Once you have changed the frequency to 125.2, press the white button between the words ‘COMM’ and ‘STBY’ to swap the active and standby frequencies (highlighted in Figure 9.6). After a second or so, you’ll hear the ATIS information.

9.3.4 Altimeter and Compass


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Figure 9.7: Altimeter calibration knob


Listen for the ‘Altimeter’ setting. If you are not using ‘real weather’, the value will be 2992, which is standard and already set on the plane. If you are using ‘real weather’, then the altimeter value is likely to be different. We therefore need to set the altimeter to the correct value. To do this, use the knob at the bottom left of the altimeter (circled in red in Figure 9.7), in the same way as you changed the radio frequency. This changes the value in the little window on the right of the altimeter, which is what you are trying to set, as well as the altitude displayed by the altimeter.

The other way to set the altimeter is to match it to the elevation above sea-level of the airport. The elevation is listed on the sectional. For KRHV it is 133ft. This means you can double-check the pressure value reported over ATIS.


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Figure 9.8: Heading adjust knob


We will also take the opportunity to set the heading bug on the compass to 350 - our bearing from KRHV to KLVK. To do this, use the red button on the compass housing (highlighted in Figure 9.8), just as you’ve done before. Use the left mouse button for small adjustments, and middle mouse button to make big adjustments. The value of 350 is just anti-clockwise of the labeled value of N (North - 0 degrees).


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Figure 9.9: Take-off from KRHV


9.3.5 Take-Off

OK, now we’ve done that we can actually take off!. In my case this usually involves weaving all over the runway, and swerving to the left once I’ve actually left the ground, but you’ll probably have better control than me. Once above 1000ft, make a gentle turn to the right to a heading of 350 degrees. As we’ve set the heading bug, it will be easy to follow. We’re aiming for a fairly prominent valley.

Continue climbing to 3,500 ft at around 500-700 fpm. Once you reach that altitude, reduce power, level off to level flight and trim appropriately. Check the power again and adjust so it’s in the green arc of the RPM guage. We shouldn’t run the engine at maximum RPM except during take-off.

9.4 Cruising

OK, we’ve taken off and are on our way to Livermore. Now we can make our life a bit easier by using the autopilot and our plane more fuel efficient by tuning the engine. We’ll also want to check we’re on-course

9.4.1 The Autopilot


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Figure 9.10: The C172 Autopilot


We can make our life a bit easier by handing some control of the aircraft over to ‘George’ - the autopilot.

The autopilot panel is located towards the bottom of the radio stack (highlighted in Figure 9.10). It is easily distinguishable as it has many more buttons than the other components on the stack. It can work in a number of different modes, but we are only interested in one of them for this flight - HDG. As the names suggest, HDG will cause the autopilot to follow the heading bug on the compass, which we set earlier.

To set the autopilot, press the AP button to switch the autopilot on, then press the HDG button to activate heading mode. While the autopilot is switched on, it will use the trim controls to keep the plane on the heading. You can change the heading bug, and the autopilot will maneuver appropriately. However, the autopilot doesn’t make any allowances for wind speed or direction, it only sets the heading of the airplane. If flying in a cross-wind, the plane may be pointed in one direction, but be travelling in quite another.

You should use the trim controls to keep a level flight. You can use the autopilot for this, but it is a bit more complicated.

Once the aircraft has settled down under the autopilot’s control, we can pay more attention to the outside world and higher level tasks.

9.4.2 Navigation


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Figure 9.11: The Calaveras Reservoir


As we noted above, we’re going to be travelling over a couple of reservoirs. When you leveled off, the first (Calaveras) was probably right in front of you. You can use them to check your position on the map. If it looks like you’re heading off course, twist the heading bug to compensate.

9.4.3 Mixture


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Figure 9.12: The Calaveras Reservoir


As altitude increases, the air gets thinner and contains less oxygen. This means that less fuel can be burnt each engine cycle. The engine in the C172 is simple and doesn’t automatically adjust the amount of fuel to compensate for this lack of oxygen. This results in an inefficient fuel burn and a reduction in power because the fuel-air mixture is too ‘rich’. We can control the amount of fuel entering the engine every cycle using the mixture control. This is the red lever next to the throttle. By pulling it out, we ‘lean’ the mixture. We don’t want the mixture too rich, nor too lean. Both these conditions don’t produce as much power as we’d like. Nor do we want it perfect, because this causes the fuel-air to explode, rather than burn in a controlled manner, which is a quick way to trash an engine.


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Figure 9.13: Mixture Control


The mixture is controlled by the red lever to the right of the yoke. You may need to pan your cockpit view to see it.

To pan the cockpit view, hold down the right mouse button Moving the mouse now pans the view. Once you can see the mixture lever clearly, release the right mouse button.


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Figure 9.14: Fuel Flow and EGT guages


Pull the mixture lever out slowly (use Ctrl-C to see the hot spots), leaning the mixture. As you do so, you’ll see various engine instruments (on the left of the panel) change. Fuel flow will go down (we’re burning less fuel), EGT (Exhaust Gas Temperature) will go up (we’re getting closer to a ‘perfect mixture’) and RPM will increase (we’re producing more power). Pull the mixture lever out until you see the EGT go off the scale, then push it in a bit. We’re now running slightly rich of peak. While at 3,500ft we don’t need to lean much, at higher altitudes leaning the engine is critical for performance.

9.5 Getting Down

Once you reach the second reservoir (the San Antonio Reservoir), we need to start planning our descent and landing at Livermore. Landing is a lot more complicated than taking off, assuming you want to get down in one piece, so you may want to pause the simulator (press ‘p’) while reading this.

9.5.1 Air Traffic Control

In the Real World, we’d have been in contact with Air Traffic Control (ATC) continually, as the bay area is quite congested in the air as well as on the ground. ATC would probably provide us with a ‘flight following’ service, and would continually warn us about planes around us, helping to avoid any possible collisions. The FlightGear skies are generally clear of traffic, so we don’t need a flight following service. If you want to change the amount of traffic in the sky, you can do so from the AI menu.

Livermore Airport is Towered (towered airports are drawn in blue on the sectional), so we will need to communicate with the tower to receive instructions on how and where to land.

Before that, we should listen to the ATIS, and re-adjust our altimeter, just in case anything has changed. This is quite unlikely on such a short flight, but if flying hundreds of milesm it might make a difference. To save time when tuning radios, you can access the Radio Settings dialog from the Equipment menu. The Livermore ATIS frequency is 119.65MHz.

An ATIS message also has a phonetic letter (Alpha, Bravo, … Zulu) to identify the message. This phonetic is changed each time the recorded message is updated. When first contacting a tower, the pilot mentions the identifier, so the tower can double-check the pilot has up to date information.

Besides the altitude and weather information, the ATIS will also say which runway is in use. This is useful for planning our landing. Normally, due to the prevalent Westerly wind, Livermore has runways 25R and 25L in use.

Once you’ve got the ATIS, tune the radio to Livermore Tower. The frequency is 118.1MHz. Depending on the level of AI traffic you have configured on your system, you may hear Livermore Tower talking to other aircraft that are landing or departing. This information is not played over the speakers, it is only displayed on the screen.

Once the frequency goes quiet, press the ’ key. This will bring up the ATC menu. Click on the radio button on the left to select what you wish to say (you only have one option), then OK.

Your transmission will be displayed at the top of the screen. It will indicate who you are (type and tail number), where you are (e.g. 6 miles south), that you are landing, and the ATIS you have.

After a couple of seconds, Livermore Tower will respond, addressing you by name and telling you what runway to use, which pattern is in use and when to contact them, for example

“Golf Foxtrot Sierra, Livermore Tower, Report left downwind runway two five left.”

To understand what this means, we’ll have to describe the Traffic Pattern.

9.5.2 The Traffic Pattern

With the number of aircraft flying around, there have to be standard procedures for take-off and landing, otherwise someone might try to land on-top of an aircraft taking off.

The Traffic Pattern is a standard route all aircraft must follow when near an airport, either taking off or landing. The traffic pattern has four stages (or ‘legs’), shown in Figure 9.15. The ‘downwind’ mentioned above refers to one of these, the one with the number 3.


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Figure 9.15: The Traffic Pattern


  1. Aircraft take off from the runway and climb. If they are leaving the airport, they just continue climbing straight ahead until clear of the pattern and then do whatever they like. If they are returning to the runway (for example to practise landing), they continue climbing until they reach a couple of hundred feet below ‘pattern altitude’. This varies from country to country, but is usually between 500ft and 1000ft Above Ground Level (AGL). This is called the upwind leg.
  2. The pilot makes a 90 degree left-hand turn onto the crosswind leg. They continue their climb to ‘pattern altitude’ and level out.
  3. After about 45 seconds to a minute on the crosswind leg, the pilot again makes a 90 degree left turn onto the downwind leg. Aircraft arriving from other airports join the pattern at this point, approaching from a 45 degree angle away from the runway.
  4. When a mile or so past the end of the runway (a good guide is when the runway is 45 degrees behind you), the pilot turns 90 degrees again onto the base leg and begins the descent to the runway, dropping flaps as appropriate. A descent rate of about 500fpm is good.
  5. After about 45 seconds the pilot turns again onto the final leg. It can be hard to estimate exactly when to perform this turn. Final adjustments for landing are made. I usually have to make small turns to align with the runway properly.
  6. The aircraft lands. If the pilot is practising take-offs and landings, full power can be applied and flaps retracted for takeoff, and the aircraft can take off once more. This is known as ‘touch-and-go’.

Most patterns at left-handed, i.e. all turns are to the left, as described above. Right-hand patterns also exist, and are marked as ‘RP’ on the sectional. ATC will also advise you what pattern is in use.

9.5.3 Approach


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Figure 9.16: Sectional extract showing approaches to Livermore


We’re approaching Livermore airport from the South, while the runways run East/West. Due to the prevailing Westerly wind, we’ll usually be directed to either runway 25R or 25L. 25R uses a right-hand pattern, while 25L uses a left-hand pattern. Both the patterns are illustrated in Figure 9.16. Depending on the runway we’ve been assigned, we’ll approach the airport in one of two ways. If we’ve been asked to land on runway 25R, we’ll follow the blue line in the diagram. If we’ve been asked to land on runway 25L, we’ll follow the green line.

We also need to reduce our altitude. We want to end up joining the pattern at pattern altitude, about 1,000ft above ground level (AGL). Livermore airport is at 400 ft above sea-level (ASL), so we need to descend to an altitude of 1400 ASL.

We want to begin our maneuvers well before we reach the airport. Otherwise we’re likely to arrive too high, too fast, and probably coming from the wrong direction. Not the best start for a perfect landing :).

So, let‘s start descending immediately.

  1. First switch off the autopilot by pressing the AP switch.
  2. Return mixture to fully rich (pushed right in). If we were landing at a high airport, we’d just enrich the mixture slightly and re-adjust when we reached the pattern.
  3. Apply carb-heat. This stops ice forming when the fuel and air mix before entering the cylinder, something that can often happen during descent in humid air. The carb-heat lever is located between the throttle and mixture. Pull it out to apply heat.
  4. Reduce power quite a bit. Otherwise we might stress the airframe due to over-speeding.
  5. Drop the nose slightly to start the descent.
  6. Trim the aircraft.

Use your location relative to the airport and the two towns of Pleasanton and Livermore to navigate yourself to the pattern following the general guide above.

Once you’re established on the downwind leg, you’ll need to report to ATC again. Do this in the same way as before. They will then tell you where you are in the queue to land. ‘Number 1’ means there are no planes ahead of you, while ‘Number 9’ means you might want to go to a less busy airport! They’ll also tell you who is ahead of you and where. For example ‘Number 2 for landing, follow the Cessna on short final’ means that there is a single aircraft in front of you that is currently on the final leg of the pattern. When they land and are clear of the runway, they’ll tell ATC, who can then tell you ‘Number 1 for landing’.

9.5.4 VASI


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Figure 9.17: On Final at Livermore with VASI on the left


Once on final, you’ll notice two sets of lights on the left of the runway (enhanced in Figure 9.17). This is the VASI and provides a nice visual clue as to whether you’re too low or too high on approach. Each set of lights can either be white or red. White means too high, red means too low. White and red together means just perfect. On a Cessna approaching at 60kts, a descent rate of about 500fpm should be fine. If you are too high, just decrease power to increase your descent rate to 700fpm. If you are too low, increase power to decrease your descent rate to 200fpm.

9.5.5 Go Around


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Figure 9.18: Missed approach at Livermore


If for some reason it looks like you’re going to mess up the landing you can abort the landing and try again. This is called a ‘Go Around’. To do this

  1. Apply full power
  2. Wait until you have a positive rate of climb - i.e. your altitude is increasing according to the altimeter.
  3. Raise your flaps to 10 degrees (first-stage).
  4. Tell ATC you are ‘going around’
  5. Climb to pattern height
  6. If you aborted on final approach, continue over the runway to re-join the pattern on the crosswind leg. If on base, fly past the turn for final, then turn and fly parallel to the runway on the opposite side from downwind to rejoin on the crosswind leg.
  7. Fly the complete pattern, telling ATC when you are on downwind, and try again.

9.5.6 Clearing the Runway

Once you’re on the ground, you should taxi off the runway, then tell ATC you are clear. At high-altitude airports, you would lean the engine to avoid fouling the spark-plugs with an over-rich mixture. Find somewhere nice to park, shut down the engine by pulling mixture to full lean, then throttle off and magnetos to off (knob on the bottom left of the panel). Switch off the avionics master switch, tie down the aircraft, then go get that hamburger!

I hope this tutorial is of some use. If you have any comments, please let me know at stuart_d_buchanan {at} yahoo.co.uk.

Chapter 10
An IFR Cross Country Flight Tutorial

10.1 Introduction


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Figure 10.1: Flying over the San Antonio Dam to Livermore. I think.


In the cross country flight tutorial, you learned about VFR flight, and in the course of the flight you were introduced to most of the flight instruments in the C172p. Now we’re going to do an Instrument Flight Rules (IFR) flight. In this flight you’ll be introduced to the remaining instruments, learn a bit about IFR flight, and learn many, many TLAs (Three-Letter Acronyms).

We’ll fly the same flight, from Reid-Hillview (KRHV), runway 31R, to Livermore (KLVK), runway 25R, only this time we’ll do it in IFR conditions: a ceiling 200 feet above ground level, and 800 metre visibility. This tutorial assumes you’ve completed the cross country flight tutorial.

10.1.1 Disclaimers

This is not intended to teach you how to fly IFR. Rather, it is meant to give a flavour of what IFR flying is like, and remove the mystery of the panel instruments not covered by the cross country flight tutorial.

I’m not a pilot. Like the previous tutorial, this information has been gleaned from various non-authoritative sources. If you find an error or misunderstanding, please let me know. Mail me at bschack-flightgear -at- usa -dot- net.

This flight was flown using FlightGear 3.0. Newer or older versions of FlightGear might be slightly different.

10.2 Before Takeoff

We need to tell FlightGear about our flight conditions. There are different ways to set our “desired” weather, but we’ll use the global weather menu. After launching FlightGear, click Environment Weather to bring up the weather dialog. In the Weather Conditions list, select CAT I minimum.

This will give us a low ceiling and reduced visibility. Unfortunately, it will also give us rather stiff winds. If you don’t want to deal with them, then you can easily turn off the winds:

Hit OK to make FlightGear accept the changes and close the dialog.

Finally, I find that the reduced visibility situations are rendered best when atmospheric light scattering is turned off: click View Rendering Options and make sure the Atmospheric light scattering box is unchecked.


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Figure 10.2: On runway 31R at KRHV


10.2.1 Flight Planning

When you look out the window, you’ll see something like Figure 10.2. Those clouds don’t look very friendly, and it’s hard to even see past the end of the runway. Maybe we should just drive there in the Cessna. We had been planning to practice ground steering anyway …

So how do you get from A to B when you can’t see? There are a variety of ways that have evolved over the years, with various advantages and disadvantages. Our flight will use all of the navigation instruments the standard Cessna C172p has, just to give a taste of what’s possible.

Our entire route, and the aids we’ll be using, are shown in Figure 10.3. Our route is in green, the navigational aids blue and red. The route looks a bit crazy — in fact, you might wonder if we’re more lost using our fancy equipment than just flying by the seat of our pants — but there is a method to the madness. Rather than overwhelming you with details by explaining it all now, I’ll explain it bit by bit as we go along.


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Figure 10.3: Green: our route, Blue: VORs and radials, Red: NDBs


10.2.2 VHF Omnidirectional Range

The first bit will involve VOR1 (VHF (Very High Frequency) Omnidirectional Range) navigation, and will get us to a point about 5 nm (nautical miles) south of Livermore.

VOR stations are indicated on the sectional by a big bluish-green circle with compass markings around the outside. I’ve helped you by marking their centers with a big blue dot as well. Reid-Hillview is very close to one, San Jose, which you can see in Figure 10.3. Near the centre of the circle, in a bluish-green rectangle, is the station information. According to the station information, it’s a VOR-DME station (I’ll explain DME later), its name is San Jose, its frequency is 114.1 MHz (or Channel 88, which is an alternative way to say the same thing), and its identifier, or “ident”, is SJC (which in Morse code is ....--- -.-.).

To tune into a VOR station, we use one of the NAV receivers, which are paired with the COMM receivers (see Figure 10.4). And we navigate using the corresponding VOR gauge. We’ll choose the NAV1 receiver (and VOR1 gauge) in this case (NAV2 would have worked just as well). Before setting the frequency, check out the VOR1 gauge. It should look like VOR1 on the left in Figure 10.5. The important thing is the red “NAV” flag. That means there’s no VOR signal, so we can’t trust the gauge.


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Figure 10.4: IFR navigation instruments


The NAV receiver has an active frequency, a standby frequency, and a tuning knob, just like the COMM receiver.2 Tune it to 114.1, and press the swap buttonNAV1 114.13. If you look at VOR1, you should notice that the red “NAV” flag has disappeared, to be replaced with a “TO” flag, as shown on the right of Figure 10.5. That means we’re receiving a signal. But is it the correct one? What if we accidentally set the wrong frequency?


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Figure 10.5: VOR1, before and after tuning


To confirm that we’re tuned into the correct VOR, we listen for its ident. If you can’t hear the ident, or if it doesn’t match the chart, don’t trust the needle. So far, you probably haven’t heard a thing. Why? Check the audio panel (see Figure 10.4). You’ll note there’s a switch for all the instruments that produce useful sounds, and NAV1 is one of them. Flip the switch up (or down — it doesn’t matter), and you should hear this: ....--- -.-..4 Nice. Flip the switch back to the centre when you get tired of listening to dots and dashes.

Back to VOR1. There’s a knob on the lower left, called the OBS (Omni Bearing Selector). As the name vaguely suggests, it is used to select a bearing. If you turn it, you should see the vertical needle, called the CDI (Course Deviation Indicator) move.5 Try to center the needle. It should center when the little arrow at the top points to somewhere around 277. That number, and the TO flag means: “Flying at a heading of 277 will lead you directly to the station”.

That’s great, except, according to our route, we don’t want to go to the station. We actually want to intercept the light blue line labelled “009” (the “9 degree radial”) coming from the station. How do we do that? Simple. Set the OBS to 9VOR1 OBS 009. When we fly across the radial, the needle will center, and the flag will say FROM. This tells us: “flying at a heading of 9 will lead you directly away from the station”, which is what we want. At that point we’ll turn right to a heading of 9.

One final thing — set the heading bug on the directional gyro to our current heading (about 310)Heading bug 310.

10.2.3 How High Are We Really?

One effect of our changing the weather conditions is that the barometric pressure is no longer the standard value of 29.92. Our altimeter needs to know the correct value, otherwise it will report the wrong altitude. This isn’t critical at takeoff, but it can make a huge difference when descending through the clouds (can you say “controlled flight into terrain”?).

As described in the cross-country flight tutorial, we get the current barometric pressure via ATIS. To recap, click AI ATC Services in Range, select our airport, and look up the ATIS frequency (it should be 125.20 MHz). Dial this frequency into COMM1 or COMM2 (remembering to flip the appropriate switch on the audio panel), listen to the ATIS report, and set the altimeter to the given barometric pressure.

We are going to be using the autopilot (see Figures 10.4 and 10.6) to hold an altitude (more on that later), so it also needs to know the barometric pressure. To do so, click the BARO button on the autopilot. You should see “29.92” displayed — this is what the autopilot thinks the barometric pressure is. Before the “29.92” disappears (within about 3 seconds), rotate the big dial to change it to the correct value.

10.3 Takeoff

We’re ready to take off. There are other preparations that we should have made, but again, in the interests of not overwhelming your brains, I’m only feeding you a bare minimum of information, and feeding it in trickles. This brings us to the most important control you have — the ‘p’ key. Use this often, especially when a new concept is introduced.

Okay. Take off, keeping a heading of 310 for nowTake off; climb on runway heading. Establish a steady rate of climb. We plan to climb to 4000 feet. There’s just one problem though — those ugly-looking clouds are standing in our way.

10.4 In the Air

If this is your first attempt at IFR flight, you will find it impossible to fly once you enter the clouds. When you enter the clouds, you will be momentarily disconcerted by the lack of visual cues. “No matter,” you then think. “I’ll just keep things steady.” In a few moments, though, you’ll probably notice dials and needles spinning crazily, and without knowing it, you’ll be flying upside down, or diving towards the ground, or stalling, or all three.

It takes practice to get used to flying without external visual clues, although it’s a skill that you definitely must master if you want to fly IFR. For now though, we’ll use “George”, the autopilot, to make this part of flying easier.

10.4.1 George I

Once you’ve established a steady rate of climb and heading, engage the autopilot by pressing the AP button. You should see “ROL” displayed on the left to show that it’s in “roll mode” — it is keeping the wings level. In the middle it will display “VS”, to show it is in “vertical speed” mode — it is maintaining a constant vertical speed. On the right it will momentarily display that vertical speed (in feet per minute). Initially, the value is your vertical speed at the moment the autopilot is turned on. In the case of Figure 10.6, the autopilot has set the vertical speed to 300 feet per minute.


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Figure 10.6: Autopilot after engaging


When you engage the autopilot, CHECK THIS CAREFULLY. Sometimes the autopilot gets a very funny idea about what your current rate of climb is, like 1800 feet per minute. Our little Cessna cannot sustain this, and if the autopilot tries to maintain this (and it will), you will stall before you can say “Icarus”. This is a bug, to be sure, and a bit annoying, but it is also a useful cautionary lesson — don’t put blind faith in your equipment. Things fail. You have to monitor and cross-check your equipment, and be prepared to deal with problems.

We want a vertical speed of around 500 to 700 feet per minute. Hit the up and down (UP and DN) buttons to adjust the vertical speed to a nice value. Take into account the airspeed as well. We want a sustainable rate of climb.

Finally, once you’re climbing nicely, hit the heading (HDG) buttonEngage autopilot; set vertical speed; engage heading mode. On the display, “ROL” will change to “HDG”, and the autopilot will turn the airplane to track the heading bug. Since you set the heading bug to the runway heading, and you took off straight ahead (didn’t you?), it shouldn’t turn much.

10.4.2 MISON Impossible

It’s around 8 nm to the 009 radial intercept, so we’ve got a bit of time. Since there’s no scenery to admire (eg, see Figure 10.7), we might as well prepare for the next phase of the flight.


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Figure 10.7: Typical IFR scenery


If you look along our route, just after we intercept the 009 radial and turn north, we pass by a point labelled MISON (see Figure 10.8 for a closeup of that section of the chart without my fat blue and green lines drawn on top. MISON is in the lower right). Just above and to the left of MISON are two crossed arrows. MISON is an intersection. We’re actually going to pass east of MISON, but the radial passing roughly from northwest to southeast through MISON (and our route) is of interest to us. We’re going to use it to monitor our progress.


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Figure 10.8: Oakland VOR and 114 radial to MISON intersection


Noting our passage of that radial isn’t strictly necessary — we can just keep flying along the 009 radial from San Jose until we need to turn. But it’s useful for two reasons: First, it’s nice to know exactly where we are. Second, it confirms we are where we think we are. If we fly and fly and never cross the radial, alarm bells should start going off.

Looking at the sectional, we see that the radial is the 114 radial from the Oakland VORTAC (VOR TACAN, where TACAN stands for Tactical Air Navigation). Oakland’s frequency is 116.8, and its ident is OAK (- - - . - - . - ). NAV2 should already be tuned to Oakland, but if it isn’t, do it now.NAV2 116.8 Turn on NAV2 in the audio panel and make sure you’re getting the correct ident.

We need to adjust the OBS, to tell VOR2 which radial we’re interested in. Set the OBS to 114VOR2 OBS 114.6 See if you can guess whether the flag should read TO or FROM when we cross the 114 radial. And see if you can guess whether the needle will move from left to right or right to left as we cross the radial.

A final note: For our purposes, there’s nothing magical about the 114 radial — we could have used 113, or 115, or 100, or 090. The reason I chose 114 is because there was a line on the map already drawn along the 114 radial, which saved me the trouble of drawing a line myself.

10.4.3 George II

As we continue towards the 009 radial intercept, let’s look a bit more closely at the autopilot. First of all, if you aren’t in the habit of trimming the airplane, you’ll probably notice a flashing “PT” with an arrow on the autopilot. The autopilot is telling you to adjust the pitch trim. I tend to ignore it because, flying with a mouse, trimming is more trouble than it’s worth. Those of you lucky people with yokes and joysticks and who find flashing lights annoying might want to trim to get rid of it.

Also, on the right there’s a big knob, the altitude select knob, which we can use to dial in a target altitude. We’re going to use it. Turn it until you see our desired cruising altitude, 4000 feet, displayed on the right. When you started turning it, “ALT ARM” should have appeared in the autopilot display (as in Figure 10.9). This indicates that you’ve selected a target altitudeSet autopilot altitude to 4000. The autopilot will maintain the current rate of climb until reaching that altitude, at which point it will level off and change from vertical speed (VS) mode to altitude hold (ALT) mode. In altitude hold mode it maintains an altitude (in this case our target altitude of 4000 feet).7 It will also politely beep 5 times when you cross 3000 feet to remind you that you’re within 1000 feet the armed altitude.


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Figure 10.9: Autopilot with altitude armed


Don’t forget that the autopilot won’t adjust the throttle, so when it levels out, the airplane (and engine) will speed up. You’ll need to adjust the throttle to get a proper cruise.

10.4.4 Staying the Course

At some point you’ll intercept the 009 radial (the VOR1 needle will centre). Turn to a heading of 009Turn to 009 upon VOR1 intercept. You can do this using the heading bug on the directional gyro if you’re using the autopilot.

Unless you’re good or lucky, the needle probably won’t be centered. We need to adjust our course. The CDI needle (the vertical needle on the VOR) tells us where to go. If it’s to the left, that means the radial is to the left, so we need to go left. Ditto for right.

It’s quite easy in theory, although in practice you may find that it’s hard to keep the needle centered, and that you are slaloming down the radial. The key is to realize this: the position of the needle tells us where we are, the motion of the needle tells us what to do.

I’ll explain. If the needle is to our left, then, yes, the radial is definitely to our left.8 But if the needle is moving towards us, that means we’re going to cross the radial, sooner or later, so our situation is improving, and we probably just need to wait for the needle to center. On the other hand, if the needle is moving away, we need to turn towards it to stop, and reverse, its motion.

Note that the amount we need to turn is difficult to guess correctly at first, so experiment. Try 10. If the needle moves too fast, cut it down to 5 (ie, turn back 5). If, on the other hand, the needle moves too slowly, double it to 20 (ie, add another 10), and see what happens.

10.4.5 Yet More Cross-Checks

Cross-checking your position is always a good thing. The intersection with the Oakland 114 radial is one wayCross OAK 114 radial. Ahead of that lies the SUNOL intersection. If you look closely, 5 separate radials join at the point, so we have an embarrassment of choices with regards to the intersecting radial. Because it will come in useful later, we’re going to use the one coming in from the upper right. Another check of the sectional reveals that this is the 229 radial of the Manteca VORTAC, 116.0 MHz, ident ECA (. - . - .. - ).

You should know the drill by now: Tune NAV2 to 116.0, set the OBS to 229, and check the ident to confirm the stationNAV2 116.0
VOR2 OBS 229
.

Meanwhile, let’s introduce another piece of gear on the panel that will cross-check the SUNOL passage. Some VOR stations have a distance capability, called DME9 (Distance Measuring Equipment). For example, San Jose does (remember it’s a VOR-DME station), as do Oakland and Manteca (VORTACs have DME capabilities).

Using DME, you can find out how far you are, in straight-line distance, from the VOR station. In our scenario, the DME isn’t necessary, but we’ll use it anyway, just to see how it works, and to reconfirm our position.

The DME is the instrument below the autopilot (refer to Figure 10.4). Make sure it’s turned on. The selector to the left of the on/off switch is probably set to N1, where “N1” means “listen to NAV1”. Since NAV1 is tuned to San Jose, it’s telling us the distance to the San Jose VOR-DME. Switch the DME to N2DME N2. It now shows us the distance to the Manteca VOR.

The DME shows you 3 things: the distance in nautical miles to the station, your speed towards or away from the station, and estimated time to the station at the current speed. Note that the distance is the direct distance from your plane to the station (called the “slant distance”), not the ground distance. Note as well that the speed is relative to the station, so unless you’re flying directly to or from the station, it will probably be lower than your true groundspeed. For example, the speed from San Jose, which is directly behind us, should be greater than the speed towards Manteca, which is off to the right.

If we look up information about the SUNOL intersection,10 it tells us that it is 33.35 nm (as measured by a DME receiver) from ECA on the 229.00 radial (that’s what “ECAr229.00/33.35” means).

Now we have two ways to confirm the SUNOL intersection: The VOR2 needle will center, and the DME will read 33.4 or so. Note that the DME doesn’t provide us with a very precise fix here because Manteca is at such an oblique angle. But it does give us a good warning of SUNOL’s impending arrival. Moreover, if it has an unexpected value (like 30), it should raise a few alarm bells.

You may be wondering what “HLD” means (the setting between N1 and N2 on the DME). It stands for “hold”, and means “retain the current frequency, regardless of whether NAV1 or NAV2 are retuned”. For example, if we switch from N2 to HLD, the DME will continue to display (and update) information to Manteca. Even if we retune NAV2, the DME will remain tuned to Manteca. This is handy, because it basically represents a third independent receiver, and in IFR flight two receivers just never seem like enough.

10.5 Getting Down

We’re getting close to SUNOL, flying along the 009 radial from San Jose, monitoring our position with the DME. At SUNOL we’ll be less than 5 nm from Livermore, somewhere down there in the clouds. Perhaps if we just descended to 700 feet or so (Livermore is at 400, the ceiling is at 750) and headed more or less directly north after SUNOL, we’d get there? A recipe for disaster my friend, and you know it.

10.5.1 Instrument Approach Procedures

As you recall from the previous tutorial, when flying VFR, you don’t just point your airplane to the nearest runway to land. You need to fly a pattern. This helps you line up, and helps prevent planes from crashing into one another, which is a Good Thing.

Similarly with IFR landings. There’s a procedure to follow. In fact, there are procedures to follow. Because of the complexity of landing in IFR conditions, there’s no single procedure for all airports. You need to check for your particular airport. In fact, you usually need to check for your particular airport, runway, and navigation equipment.

Our airport is Livermore (KLVK). Let’s check the information for that airport. Go to http://www.airnav.com/airport/KLVK to see what they’ve got. Down near the bottom, we have IAPs (Instrument Approach Procedures). There are two listed for runway 25R. One is an ILS (Instrument Landing System) approach, the other a GPS (Global Positioning System) approach. Our plane has no GPS, but it does have ILS capabilities (I’ll explain ILS later), so we’ll choose that.

Although Livermore only has two different instrument approach procedures, big airports have many many more. If you look at nearby San Francisco, you’ll see they have a slew of procedures. There are ILS procedures, GPS procedures, LDA procedures, VOR procedures, … I wouldn’t be surprised if they had a procedure for someone with a sextant and an hourglass in there. To learn IFR flight, you’ll need to master all of them.

Back to Livermore. If you download the procedure, you’ll see something like Figure 10.10 (except for the colour). It’s pretty overwhelming at first — it compresses a lot of information in a small space. We’ll ignore as much as we can, restricting ourselves to the three parts that have been coloured in. And we’ll do those parts on a “need to know” basis — we’ll only look at them when we really have to.


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Figure 10.10: ILS approach plate for Livermore runway 25R


Where to start? At the beginning of course. An IAP will have one or more Initial Approach Fixes (IAFs). These are your entry points to the approach procedure and can be found in the “plan view”, which I’ve coloured purple in Figure 10.10. Our IAP lists two, one in the middle and one on the right (see Figure 10.11 for a close-up).


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Figure 10.11: Initial approach fixes


An IAF is a fix, and a fix is an identifiable point in space. In fact, we’ve already encountered another kind of fix, namely a VOR intersection. Fixes are also usually named (eg, MISON, SUNOL). The IAF on the right is named TRACY, and consists of a radial, a distance, and an altitude. Specifically, it’s 15 DME (15 nm as measured by a DME receiver) along the 229 radial from the ECA (ie, Manteca) VOR.

10.5.2 Nondirectional Beacons

However, we’re not going to use TRACY as our IAF. We’re going to use the IAF in the middle, which is a marker (LOM stands for “Locator Outer Marker”). We’ll worry about what an outer marker is later. For now let’s concentrate on the locator part. The locator in an LOM is an NDB11 (nondirectional beacon). It’s a bit like a VOR, in that it can be used to determine your heading and navigate from place to place. Like a VOR, it has a name (REIGA, in this case), a frequency (374 kHz), and an ident (LV, or. - . .. . . - in Morse). NDBs also appear on sectionals, as fuzzy red circles with a small circle in the middle, with their identification information placed in a red box nearby. (see Figure 10.12 for a closeup. Don’t confuse the NDB, which is fuzzy, with the solid red circle on the left, nor the circle below with the “R” inside).


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Figure 10.12: REIGA nondirectional beacon


An NDB station basically broadcasts a signal that says “I’m over here”, and the receiver on the plane can receive that signal and tell you, the pilot, “the station is over there”. You just need to tune the receiver and monitor the correct instruments. The receiver, labelled ADF (Automatic Direction Finder) Receiver, and the corresponding instrument, also labelled ADF, are shown in Figure 10.4.

To tune into REIGA, turn the tuning knob on the receiver until 374 is displayed as the standby (STDBY) frequencyADF 374. As usual, use the middle mouse button for big changes (100 kHz in this case), and the left mouse button for small changes (1 kHz). Then hit the swap button (labelled “FRQ”). The 374 is now displayed as the selected (SEL) frequency. The needle on the ADF should swing around, eventually pointing ahead to the right, to REIGA. But it might not. Why? Because the receiver might be in antenna mode (as show by the “ANT” in the upper-left portion of the display).12 If it is in antenna mode, hit the ADF button so that “ADF” shows. Now the needle should swing to point to REIGA. Like VORs, to be sure we’re really tuned into the right station, we need to hear the ident as well, so hit the ADF switch on the audio panel and check.

Notice there’s no OBS to set for an ADF — the needle just points to the station, which is nice. This leads us to our first rule for ADFs:

ADF Rule 1:
The needle points to the station.

Pretty simple. In fact, you may not think it merits a “rule”, but it’s important to emphasize the difference between ADFs and VORs. A VOR, remember, tracks a single radial, which you specify by turning the OBS. An ADF has a knob, and a identical-looking compass card, so it’s tempting to believe it acts the same way. It doesn’t. Turn the ADF heading knob (labelled “HD”) and see what happens. The compass card moves, but the arrow doesn’t. It just points to the station.

In our current situation, where we just want to fly to REIGA, that’s all we need to know to use the ADF. If the needle points “over there”, then we’ll fly “over there”, and eventually we’ll pass over REIGA. However, for the sake of practice, and because it will be necessary later, I’m going to give the second rule for ADFs, which explains what the compass card is there for:

ADF Rule 2:
If the compass card reflects our current heading, then the needle gives the bearing to the station.

In other words, the compass card gives “over there” a number.

Now we’re ready to head to REIGA. Rotate the ADF heading knob until our current heading is at the top (basically, the ADF should match the directional gyro). When we pass the SUNOL intersection, look at the ADF needle, and set the DG bug to that heading (I assume you’re using the autopilot. If not, just turn to that heading). At the end of the turn, the ADF needle should point straight ahead.Cross SUNOL; turn to REIGA And if it doesn’t, adjust your heading so that it does.13

By the way, the closer you get to REIGA, the more sensitive the needle becomes to changes in your heading. Don’t go crazy trying to keep the needle centered as you get close. Maintain a steady heading, and get ready for the …

10.5.3 Procedure Turn

So, once we hit REIGA, do we just turn left and head down to the runway? Ah, if only life were so simple. No, we turn right, away from the airport, and do a procedure turn. We know there’s a procedure turn because of the barbed arrow in the plan view (see Figure 10.13). As you can see if you follow the arrow, we need to fly away, on a heading of 075, then turn left 45 to a heading of 030. We do a U-turn (to the right, away from the airport — that’s one of the rules about procedure turns) to come back at 210, then a 45 right turn to 255, heading straight towards the runway. All of this turning gives us time to set ourselves correctly on course, at the right altitude, to land on 25R.


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Figure 10.13: Livermore ILS procedure turn


Hmmm. I mentioned “right altitude”, but how do we know that is? That’s down below, in the profile view (the yellow part of Figure 10.10). You can see that at the top is the LOM, our IAF. Now follow the arrows. After the IAF, we head out at 075. During the procedure turn we can descend to 3300 feet, but no lower (that’s what the line under the 3300 means). After we finish our procedure turn and are heading back at 255, we can descend to 2800 feet, but no lower, until we intercept the glide slope.

One thing the instrument approach procedure does not tell you is the length of the procedure turn. The only constraint is that you must not fly more than 10 nm away from the NDB. You’ll notice there’s a 10 nm circle drawn around it in the plan view, and a note in the profile view saying “Remain within 10 NM”. They’re not kidding. So, since we fly at around 110 knots, two minutes on each leg is reasonable — two minutes at 075, and two minutes at 030. On the way back we don’t care about times — we just want to intercept 255.

So, after we pass REIGA, turn right to 075. Our ADF receiver has a built-in timer, so we’ll use that to time our two-minute leg. Hit the “FLT/ET” (flight time/elapsed time) button. The “FRQ” in the middle of the display will disappear, “FLT” will appear on the right, and the standby frequency will be replaced by a time. This is the total flight time, and cannot be changed, except by cycling the power. Hit “FLT/ET” again. Now you’ll see “ET” displayed, and a time, probably the same as the flight time. To reset the elapsed time, hit the next switch, labelled “SET/RST”. The timer should reset to 0, then start counting up (see Figure 10.14).14 In elapsed time mode, each time you hit “SET/RST”, the time resets to 0. If you want to see the standby frequency again, hit “FRQ” once. The timers will continue to run.


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Figure 10.14: ADF with timer running


10.5.4 Chasing the Needle

When we approached REIGA, we weren’t particularly concerned about our course — we just aimed for REIGA. Now, however, our course is important. We want to be flying directly away from REIGA on a course of 075Cross REIGA; fly at 075 away from REIGA for two minutes.

Now, in an ideal world, after we turned to 075, the ADF needle would be pointed directly behind you (ie, we’d be on course). Probably it isn’t, so we need to adjust our course. The key to adjusting our course is ADF Rule 2. If we’ve set the compass card correctly, then the needle shows us the current NDB bearing. If we turn and fly until we intercept the 255 bearing, then turn to 075, we’ll be right on course.

Figure 10.15 shows what I mean. In the figure, the plane, flying along the green line, is initially off course.15 The heading is correct, 075, but the station is at 225, not 255. To correct this, we turn right (remembering to adjust the ADF compass card to match our new heading). As we fly on this new heading, we get closer to the correct position, crossing the 235 and 245 bearings (shown in red). Finally, when we the ADF needle points to 255, we turn left to 075, and readjust the ADF compass card.16 We are now on course.


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Figure 10.15: Getting back on course


Of course, even when you get back on track, that won’t be the end of the story. Your airplane drifts; your mind drifts; your compass drifts; the wind pushes you around. What you find is that you will be constantly making little corrections. That’s okay, as long as we’re close. And anyway, before long (2 minutes actually), we’ll turn left 45 to 030 as part of our procedure turn, at which point we’ll just ignore the NDB anyway. Sigh. All that effort for just 2 minutes. Hardly seems worth it.

10.5.5 FOOTO Time

While you’re flying outbound, take an occasional look at VOR2, tuned to Manteca, and the DME. Assuming the OBS is still at 229, and the DME still tuned to N2, at some point the needle should center, meaning you’ve crossed the 229 radial, and, if you’re on course, at the same time the DME should read 20.8. How do I know that? If you look at the approach plate (Figure 10.10), you’ll notice an intersection, named FOOTO. FOOTO is on the approach, and is defined to be 20.8 DME from ECA. Although this intersection is not strictly necessary for us, it comes for free, and provides good confirmation of our position both outbound and, later, inbound.

Depending on how fast you’re flying, you’ll probably pass FOOTO close to the time your two minutes at 075 are up. At the end of two minutes, turn left 45 to 030. Reset the timer, and fly for another two minutes on this heading.

10.5.6 George III

This leg is relatively uneventful, so we’ll take advantage of the lull in the action to descend to 3300.Turn left to 030; fly for two minutes while descending to 3300 Before descending, check the KLVK ATIS (it should be 119.65 MHz) and make sure your altimeter is correct.

Assuming you’re using the autopilot, you will need to do a few things to descend:

  1. If you’re in altitude hold (ALT) mode, you need to get back into vertical speed (VS) mode. Press the ALT button — the “ALT” in the middle of the display should change to “VS”, and your current vertical speed (probably 0) should be displayed momentarily on the right.
  2. Click the DN button until you get a vertical speed of -500 feet per minute.
  3. If you want to set the target altitude, like before, rotate the big knob on the right until “3300” shows up on the right side of the display. “ALT ARM” should appear on the bottom.

Note that if you’re using the autopilot to descend, it will just push the nose down, like a bad pilot, so the airplane will speed up. We want to go down, but we don’t want to speed up, so we need to reduce engine RPMs to keep the speed at 110 knots. Later, when you level off at 3300 feet, you’ll have to increase power again.

If you’re flying manually, then you just need to adjust the engine to get the descent rate you want — the plane should stay magically at 110 knots if it’s already trimmed for 110.

10.5.7 ILS Landings

While descending, we also need to start considering how we’re going to intercept 255 on the way back and follow it down to the runway. You might think we’re going to use the NDB like we did on the outbound leg, but at this point, the NDB is not good enough. This is an ILS landing, a so-called “precision” landing, and an NDB is just not precise enough. It can get us close to the runway, but not close enough.

So, we’re going to switch over to our ILS system. It is much more accurate horizontally. As well, it offers vertical guidance, something which the NDB does not give at all. And hey, it also gives you something else to learn in our few remaining minutes so that you don’t get bored.

As with NDB and VOR navigation, the ILS system17 has a transmitter (or transmitters — a localizer and a glide slope) on the ground, and a receiver and a gauge in the aircraft. The receiver, it turns out, is just a NAV receiver, of which we have two. The gauge is like a VOR indicator, but it has an added glide slope indicator, which is a horizontal (you hope) needle. Like a VOR, the vertical needle shows whether you’re left or right. The horizontal needle shows whether you’re high or low. Our ILS gauge is our old friend VOR1.

As you might have guessed, the localizer has a frequency and ident associated with it (there’s no need to tune the glide slope separately. If you tune the localizer, you’ve tuned the glide slope). This is shown on the approach plate in two places: at the top left corner, and in the plan view by the runway (see Figure 10.16). As we can see, the frequency is 110.5 MHz, and the ident is I-LVK (. .. - . .. . . - - . - ).


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Figure 10.16: Livermore 25R localizer


If you look at VOR1 now, it should be showing a red “GS” flag (this can be seen in Figure 10.5). This indicates that there is no glideslope signal. Now tune NAV1 to 110.5NAV1 110.5. The red “GS” flag should disappear. Check for the ident. Sounds lovely, doesn’t it? That localizer is going to save your bacon and get you out of this interminable soup. When you tuned into the localizer, you’ll also have noticed the ILS needles move. And the OBS? Well, it’s useless. Try moving it. No matter how you turn it, the needles don’t move in response. That’s by design. A localizer is basically a VOR with one radial, the approach heading. We don’t care about any others, so we don’t need an OBS to declare interest in any others. However, it does serve as a useful reminder, so move the OBS to 255, our desired headingVOR1 OBS 255.

10.5.8 Intercepting the Localizer

We’re now ready to intercept the ILS localizer. When the two minutes on the 030 leg have passed, make your U-turn to the right to 210Turn right 180 to 210. Soon after you complete your turn, the vertical (localizer) needle on the ILS will begin to move. And it will move fast, much faster than the ADF and VOR needles didIntercept localizer. A localizer is 4 times as sensitive as a VOR, relatively small movements of the aircraft make big changes in the needles. You’ll probably overshoot, but don’t worry, because we have around 5 or 10 minutes to get things straightened out.

Just remember: don’t chase the needles. That mantra is now more important than ever. Those needles are sensitive — if you just turn left when the localizer needle is to the left and right when it’s to the right, you’ll be flying like a drunken sailor. If you’re lucky, the runway will be passing underneath you as you swing across the track for the umpteenth time. Luck, though, is something we should not be relying on. Determine on how the needles are moving before making your move.

Now that you’re heading back inbound at 255, slow to 75 knots, drop a notch of flaps, and descend to 2800 feet (but no lower)Slow to 75 knots; drop a notch of flaps; descend to 2800. And check for the inbound passage of FOOTO to confirm your position. And pat your head and rub your stomach.

10.5.9 Intercepting the Glide Slope

As we fly towards the runway, don’t forget to look at the horizontal needle, the glide-slope needle. When we intercepted the localizer, it should have been high above us, because we were actually under the glide slope. As we levelled out at 2800, the glide slope started coming “down” to us. Eventually, you should see the needle start to move down. When the needle is horizontal, that means you’re on the glide slope.18 And, soon after we intercept the glide slope, we should pass over the outer marker. Several things will happen more or less simultaneously, all of which confirm your position:

  1. You’ll hear a continuous series of dashes.
  2. The blue light labelled “O” above COMM1 will flash.
  3. The ADF needle will swing around.

Once on the glideslope, we need to start descending. What’s a good rate? It depends on our groundspeed. In our case, we’re going at 75 knots (there’s almost no wind, so our airspeed and groundspeed are the same), and it turns out that we need to descend at around 400 feet per minute. With the autopilot, that’s pretty easy — just dial in -400, and you’re set (but remember to reduce power to keep our speed at 75 knots, or you’ll hit the runway going pretty fast, and be prepared to adjust things if you drift above or below the glide slope).Intercept glideslope; cross outer marker; drop second notch of flaps

Without the autopilot, it’s also pretty easy — just reduce power. How much? In this case, with our plane, to around 1700 RPM. Again, it depends on many things — plane, elevation, winds, weight, …, so you’ll have to adjust things if you see the glide-slope needle start to move up or down. Like the localizer needle though, … (are you ready?) DON’T CHASE IT. Watch how it’s moving, then make your adjustment.

Since we’re on final approach, you might want to drop a second notch of flaps. This will affect your trim, and you’ll have to adjust power a bit as well.

10.5.10 Touchdown, Almost

After all the excitement of the procedure turn, it will seem like a long way down to the runway from the outer marker. There’s not much to do but stare at those needles. In fact, you’ll probably stare at them like you’ve never stared at them before. Take a look around at the other gauges too, though — they have useful things to tell you. Is our airspeed okay? We don’t want to stall. RPMs about right? If flying manually, you’ll want to constantly check the attitude indicator and directional gyro. This being a simulator, we don’t have to worry about oil pressure and engine temperature, but you might want to glance over there anyway, just to get into the habit. And I hope you’ve done things like set the mixture to full rich (you did lean it out while cruising, didn’t you?). If you want, you can lower the flaps completely as you get closer.

10.5.11 A Confession

I’ve actually made you do more work than you have to. We’ve been using the autopilot as a fancy steering wheel, but it’s capable of more than that. You may have noticed that the autopilot has some buttons I haven’t explained — NAV, APR, and REV. Well, using those buttons, the autopilot can:

NAV:
Track a VOR radial.
APR:
Do a direct ILS approach, tracking both the localizer and the glideslope.
REV:
Intercept the ILS before the procedure turn (ie, head away from the localizer.

So, in fact, even more of the work you’ve done could have been done by the autopilot. After takeoff, you could have asked it to track the 009 radial from SJC all the way to SUNOL in NAV mode; at SUNOL, you could have asked it to fly the “back-course approach” from I-LVK in REV mode; done the procedure turn in HDG mode; finally, tracked the localizer and glideslope in APR mode.

However, I didn’t give you this information for two reasons. First, flying by hand (even with the autopilot gently holding your hand, as we’ve been doing) gives you a better idea of what’s happening. Second, the autopilot doesn’t behave quite as the official manual says it should for some of these functions — best stick to the features that are known to work well.

10.5.12 Touchdown, Not

Although ILS approaches can get us close to the runway, closer than VFR, NDB, or VOR approaches can, we still need some visibility to land,19 so we need a way to decide if landing is possible or not. That’s what the landing minimums section of the procedure plate is for (coloured green in Figure 10.10). In the category labelled “S-ILS 25R” (that’s us), you’ll see “597-1/2 200(200-1/2)”. This tells us that we can track the glide slope down to an altitude of 597 feet (200 feet above the runway). At 597 feet we make our decision — if we can’t see the runway, then we have to execute a missed approach. 597 feet is our decision height (DH).

In addition to the altimeter, this particular approach also has another indication that we’re close — a middle marker (MM). This marker will sound — in this case, a dot dash series — and the yellow light labelled “M” above COMM1 will flash. Passage over the middle marker should coincide with reaching decision height.20

So, what if you can’t see the runway at decision height? As you might have expected, just as you can’t land willy-nilly, you can’t just go around willy-nilly. There’s a Procedure. A Missed Approach Procedure. This is shown in several places on the approach plate (see Figure 10.17): At the top, where it says “MISSED APPROACH”, in the plan view, where you can see a dashed arrow coming off the end of the runway and a dashed oval on the right, and in the profile view, where a series of boxes shows graphically what to do. In our case, these all tell us to:

  1. Climb straight ahead to 1100 feet
  2. Make a climbing right turn to 3000 feet
  3. Fly to REIGA
  4. Fly outbound from REIGA at 062
  5. Fly a holding pattern at the TRACY intersection


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Figure 10.17: Missed approach procedure


The holding pattern, as you might have guessed, is a place where you can “park” while sorting things out, and has its own set of procedures and techniques which we won’t go into here, because …

10.5.13 Touchdown

In our ideal simulator world, you probably won’t have to execute a missed approachSight runway; disengage autopilot; cross middle marker. Assuming you stayed on the glide slope, you should have popped out of the murk at the decision height, and with 800 metre visibility, the runway should have been in view soon after. With the runway in sight, you could then turn wildly to get on course21 (it’s very hard to be lined up perfectly) and land “normally” (which for me involves a lot of bouncing around and cursing)Land; eat hamburger. Park the plane, then stagger out of the cockpit and have another hamburger!


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Figure 10.18: On course, runway in view. We’re going to live!


10.6 Epilogue

That was a lot of information in a short time, a rather brutal introduction to ILS flying. Hopefully, instead of turning you off, it has whetted your appetite for more, because there is more. Some of the major issues I’ve ignored are:

Wind
This is a big one. Flying IFR in a crosswind affects everything you do, and you need to be aware of it or your navigation will suffer.
Flying without the autopilot
George tries his best, but he’s not completely trustworthy. You have to be prepared to go it alone.
DG precession
The directional gyro in the c172p is not perfect. Over time, the values it gives you are less and less reliable — it precesses. It needs to be periodically calibrated against the compass (using the OBS knob on the DG to adjust it).
IFR charts
We used sectionals, which are really intended for VFR flight. There are a whole set of charts devoted exclusively to IFR flight.
ATC
The other people out there need to know what you’re doing. As well, they’ll probably tell you what to do, including to ignore the approach plate you so fastidiously studied.
SIDs/DPs, Airways, and STARs
This tutorial introduced IAPs, which are standard ways to make approaches. In IFR flight, there are standard ways to leave airports (Standard Instrument Departures, SIDs, or Departure Procedures, DPs), standard ways to travel between airports (airways), and standard ways to go from airways to IAPs (Standard Terminal Arrival Routes, STARs).
Holding Patterns
Most missed approaches end in a holding pattern somewhere, so you’d better know how to fly them.
GPS
Our Cessna doesn’t have a GPS, but nowadays most small planes do, and GPS is rapidly replacing radio-based navaids.

If you want to learn more, try the following resources:

Chapter 11
A Helicopter Tutorial

11.1 Preface

First: in principle everything that applies to real helicopters, applies to FlightGear. Fundamental maneuvers are well described here:
http://www.cybercom.net/˜copters/pilot/maneuvers.html Some details are simplified in FlightGear, in particular the engine handling and some overstresses are not simulated or are without any consequence. In FlightGear it is (up to now) not possible to damage a helicopter in flight.

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The helicopter flight model of FlightGear is quite realistic. The only exceptions are “vortex ring conditions”. These occur if you descend too fast and perpendicularly (without forward speed). The heli can get into its own rotor downwash causing the lift to be substantially reduced. Recovering from this condition is possible only at higher altitudes. On the Internet you can find a video of a Seaking helicopter, which got into this condition during a flight demonstration and touched down so hard afterwards that it was completely destroyed.

For all FlightGear helicopters the parameters are not completely optimized and thus the performance data between model and original can deviate slightly. On the hardware side I recommend the use of a “good” joystick. A joystick without springs is recommended because it will not center by itself. You can either remove the spring from a normal joystick, or use a force feedback joystick, with a disconnected voltage supply. Further, the joystick should have a “thrust controller” (throttle). For controlling the tail rotor you should have pedals or at least a twistable joystick - using a keyboard is hard. FlightGear supports multiple joysticks attached at the same time.

11.2 Getting started

The number of available helicopters in FlightGear is limited. In my opinion the Bo105 is the easiest to fly, since it reacts substantially more directly than other helicopters. For flight behavior I can also recommend the S76C. The S76C reacts more retarded than the Bo.

Once you have loaded FlightGear, take a moment to centralize the controls by moving them around. In particular the collective is often at maximum on startup.

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The helicopter is controlled by four functions. The stick (joystick) controls two of them, the inclination of the rotor disc (and thus the inclination of the helicopter) to the right/left and forwards/back. Together these functions are called “cyclic blade control”. Next there is the “collective blade control”, which is controlled by the thrust controller. This causes a change of the thrust produced by the rotor. Since the powering of the main rotor transfers a torque to the fuselage, this must be compensated by the tail rotor. Since the torque is dependent on the collective and on the flight condition as well as the wind on the fuselage, the tail rotor is also controlled by the pilot using the pedals. If you push the right pedal, the helicopter turns to the right (!). The pedals are not a steering wheel. Using the pedals you can yaw helicopter around the vertical axis. The number of revolutions of the rotor is kept constant (if possible) by the aircraft.

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11.3 Lift-Off

First reduce the collective to minimum. To increase the rotor thrust, you have to “pull” the collective. Therefore for minimum collective you have to push the control down (that is the full acceleration position (!) of the thrust controller). Equally, “full power” has the thrust controller at idle. Start the engine with }. After few seconds the rotor will start to turn and accelerates slowly. Keep the stick and the pedals approximately centered. Wait until the rotor has finished accelerating. For the Bo105 there is an instruments for engine and rotor speed on the left of the upper row.

Once rotor acceleration is complete, pull the collective very slowly. Keep your eye on the horizon. If the heli tilts or turns even slightly, stop increasing the collective and correct the position/movement with stick and pedals. If you are successful, continue pulling the collective (slowly!).

As the helicopter takes off, increase the collective a little bit more and try to keep the helicopter in a leveled position. The main challenge is reacting to the inadvertent rotating motion of the helicopter with the correct control inputs. Only three things can help you: practice, practice and practice. It is quite common for it to take hours of practice to achieve a halfway good looking hovering flight. Note: The stick position in a stable hover is not the center position of the joystick.

11.4 In the air

To avoid the continual frustration of trying to achieve level flight, you may want to try forward flight. After take off continue pulling the collective a short time and then lower the nose a slightly using the control stick. The helicopter will accelerate forward. With forward speed the tail rotor does not have to be controlled as precisely due to the relative wind coming from directly ahead. Altogether the flight behavior in forward flight is quite similar to that of an badly trimmed airplane. The “neutral” position of the stick will depend upon airspeed and collective.

Transitioning from forward flight to hovering is easiest if you reduce speed slowly by raising the nose of the helicopter. At the same time, reduce the collective to stop the helicopter from climbing. As the helicopter slows, “translation lift” is reduced, and you will have to compensate by pulling the collective. When the speed is nearly zero, lower the nose to the position it was when hovering. Otherwise the helicopter will accelerate backwards!

11.5 Back to Earth I

To land the helicopter transition to a hover as described above while reducing the altitude using the collective. Briefly before hitting the ground reduce the rate of descent slowly. A perfect landing is achieved if you managed to zero the altitude, speed and descent rate at the same time (gently). However, such landing are extremely difficult. Most pilots perform a hover more or less near to the ground and then decent slowly to the ground. Landing with forward velocity is easier, however you must make sure you don’t land with any lateral (sideways) component to avoid a rollover.

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11.6 Back to Earth II

It is worth mentioning autoration briefly. This is a unpowered flight condition, where the flow of air through the rotors rotates the rotor itelf. At an appropriate altitude select a landing point (at first in the size of a larger airfield) and then switch the engine off by pressing {. Reduce collective to minimum, place the tail rotor to approximately 0˚ incidence (with the Bo push the right pedal about half, with As350 the left). Approach at approximately 80 knots. Don’t allow the rotor speed to rise more than a few percent over 100%, otherwise the rotor will be damaged (though this is not currently simulated). As you reach the ground, reduce the airspeed by lifting the nose. The descent rate will drop at the same time, so you do not need to pull the collective. It may be the case that the rotor speed rises beyond the permitted range. Counteract this by raising the collective if required. Just above the ground, reduce the descent rate by pulling the collective. The goal is it to touch down with a very low descent rate and no forward speed. With forward speed it is easier, but there is a danger of a roll over if the skids are not aligned parallel to the flight direction. During the approach it is not necessary to adjust the tail rotor, since without power there is almost no torque. If you feel (after some practice), that autorotation is too easy, try it with a more realistic payload via the payload menu.

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