Attitude Hold - Holds the aircraft in the pitch attitude it has when the autopilot is turned on.
Wing Leveling - Holds the wings level (no heading control).
Yaw Damper - Dampens out yaw to keep the tail from swinging.
Altitude Hold - Keeps the aircraft at a given altitude.
Heading Hold - Keeps the aircraft on a given heading.
Airspeed Hold - Keeps the aircraft at a given airspeed.
Mach Hold - Keeps the aircraft at a given mach number.
TOGA Control - Take off/go around mode. Automatically advances the throttles for takeoff or go around.
Nav Tracking - Tracks input from the Nav radio or GPS.
Approach Tracking - Tracks localizer/ILS/backcourse depending on selection.

Some of the functions are exclusive: for example, you can't have heading hold on at the same time as wing leveling. Depending on the aircraft, the autopilot in Flight Simulator 2002 (FS2002) will look different; in some aircraft it's part of the radio stack (Cessna, Mooney), while in others it's part of the main panel (B737, Kingair, B747, to name a few). Figure 1 at the end of this tutorial shows screenshots of some of the autopilots in FS2002. Although they look different, they all perform the same functions. (Note that some autopilot functions are not available on some of the aircraft.)

The overall procedure for using an autopilot is as follows (I'll cover the details later):

1. With the autopilot off set up the autopilot functions that you will be using. For example if you want to use altitude hold enter the altitude and a vertical speed you want to use to climb (or descend) to that altitude. For heading, enter the heading.
2. Then after takeoff (or when specified by the flight manual) turn the autopilot on. On aircraft like the Cessna when you click on one of the autopilot buttons (such as 'HDG' the autopilot turns on automatically. On other aircraft such as the 747 you can press the buttons for the function (i.e. 'ALT') and that function will ready to use but nothing will happen until you press the autopilot command or on button.

Using the Boeing 747-400 autopilot as an example let's go through each of the functions. These will be available on almost all aircraft but they may be in a different place, have slightly different labels (such as 'A/P' instead of 'CMD') or look slightly different.

To get the most out of this guide, you might want to get the 747-300 up to a safe altitude (either by flying it there or slewing) and then save the flight. Then try each of the steps given.

The simplest function of an autopilot is to serve as a wing leveler. In this mode the autopilot simply keeps the wings level; whether or not the aircraft maintains altitude or airspeed depends on the pilot. Some autopilots go into wing level mode as soon as you turn them on (assuming heading mode is not selected), while others - such as the B777 and B737 - have a button to enable the wing leveler function.

The yaw damper function eliminates unwanted yaw (movement around the vertical axis, swinging of the tail). For aircraft that have this feature - such as the KingAir - simply turn it on by clicking the 'Y/D' button.

Attitude hold simply keeps the pitch attitude at whatever it was when the autopilot was turned on. This function does not have a button in FS2002. Use the keys CTL + T.

A more complicated function is heading. The autopilot elements that relating to heading are shown in below, outlined in red boxes. There is a set of thumbwheel switches to set the heading, a knob to turn that increases or decreases the heading, and two buttons: one to tell the autopilot whether to use the heading dialed in or to use the NAV/GPS system; and one to provide heading information.

First, dial in the heading you want (in this case 360) using one of several methods. These methods can be used on most of the autopilot functions so they will be given here once and not repeated for each function.

1. Move the mouse to the left side of the thumbwheel switches and you will see a hand with a minus sign ("-"). Hold the left mouse button down to decrease the heading. Move the mouse to the right side of the thumbwheel switches and you will see the hand with a plus sign ("+"). Hold the left mouse button down to increase the heading.
2. Move the mouse to the left side of the 'SEL' knob and you will see the hand with a minus sign. Hold the left mouse button down to decrease the heading shown in the thumbwheel switches. Move the mouse to the right side of the 'SEL' knob and hold the left mouse button down to increase the heading shown in the thumbwheel switch.
3. Press CTL + SHIFT + H (the control, shift, and H keys all at once). This will select the heading thumbwheel switches. Then use the minus key to decrease the reading or the equal key ("=") to increase the reading.

Second, push the button labeled 'HDG' to the left of the 'SEL' knob. On the Boeing 747-400 the button will show a yellow bar and the heading function will be ready for use. To allow the autopilot to control the heading, push the button labeled 'CMD' (it's outlined with a small box in the picture below). This turns on and enables the autopilot. If you do not turn on the 'CMD' button the autopilot will just sit there and do nothing. (See the Notes section at the end of this tutorial for additional information on the heading and wing leveler function.)

For some aircraft you use the heading bug on the directional gyro ('DG') instead of thumbwheel switches. The KingAir works the same way except that you adjust the knob at the bottom left of the Horizontal Situation indicator ('HIS'). See the pictures below.

Now let's take the altitude hold function, which is used to keep the aircraft at a constant altitude. The autopilot controls that relate to altitude hold are outlined below in the red rectangle. There are two sets of controls - one for the altitude itself and another for the vertical speed. If you are not at the desired altitude you have to set the vertical speed that you want to ascend or descend to.

1. Set the altitude either by clicking on the thumbwheel switches or using the knob BELOW the altitude numbers and to the left of the 'HOLD' button. You can use the techniques described for setting the heading.
   
2. Click on the 'HOLD' button and the button's bar should light up.
3. Adjust the vertical speed to the desired rate of ascent or descent either by clicking on the vertical speed numbers or using the wheel between the altitude and vertical speed controls.
4. Click on the 'V/S' button and the button's bar should light up.
5. Push the 'CMD' button (if it's not already on) to enable the autopilot.

The airspeed and mach hold functions are closely related. Normally, airspeed is used to display the plane's speed until it gets to an altitude high enough that compressibility and other effects make airspeed inaccurate. At that point mach number is used for speed indication.

To set a target airspeed or mach number, do the following:

1. Turn the autothrottle off. This is the toggle switch to the left of the mach button and above the F/D button.
2. Click on the 'SPD' button to get the proper display. The airspeed display will have three digits with no decimal point, while the mach number will have a decimal point followed by two digits.
3. Dial in the desired target airspeed by using the thumbwheel switches or the knob below the 'IAS/MACH' switches.

To track navaids, the autopilot works in conjunction with the navigation radios or the GPS. To use the nav radio a switch on the aircraft panel is set to 'NAV' (on the 747 the switch is just above the multifunction display, while on the 777 it's on the engine instrument and crew alert display).

1. Select 'NAV' or 'GPS' on the aircraft panel (NOT the autopilot panel).
2. If 'NAV' is to be used tune the nav 1 radio and set the OBS of the nav 1 radio to the proper radial. If the GPS is to be used make sure a flight plan is loaded.
3. On the autopilot press the 'NAV' and 'CMD' buttons and the autopilot will follow the course set by either the GPS or nav radio 1, depending on your selection in step 2.

In FS2002 only, nav radio 1 can be used by the autopilot to fly a course. If 'GPS' mode is selected you can't rotate the OBS knob or set a course in the HIS using the autopilot. If you need manual control of the display, move the 'GPS/NAV' switch back to 'NAV'.

Approach tracking is the same as nav tracking except that the autopilot will track the ILS, localizer, or back course approach set into nav radio 1.

1. Select 'NAV' on the aircraft panel (NOT the autopilot panel).
2. Tune the nav 1 radio to the proper frequency for the ILS or localizer and set the OBS of the nav 1 radio to the proper radial. (Note that an ILS only has one radial so it won't make any difference to the autopilot, but it's a handy aid to remind you of what course you are supposed to fly to stay on the localizer.)
3. On the autopilot press the 'APR' or 'BC' and 'CMD' buttons and the autopilot will fly intercept the radial and fly the approach. If your are flying a back course approach you must push the 'BC' button to let the autopilot know it's a back course approach.

Takeoff/Go around mode (TO/GO) allows the autopilot to take the aircraft off or execute a go around. In this mode the autopilot advances the throttles and pitches the nose up to a preset value. The auto throttle must be armed for this mode to work. TO/GO mode is selected by a button on the throttle quadrant.

Notes

Some additional suggestions for the FS2002 autopilots:

• When first turned on the FS2002 autopilot goes into wing leveler mode. This is typical of the real George but hasn't been modeled in FS before.
• If you select the heading, the wing leveler will go off. When you disable heading the wing leveler function comes back on. To override this behavior add the following lines to the autopilot section of the aircraft.cfg file.
  use_no_default_bank = 1
  use_no_default_pitch = 1