The Advanced Autopilot (Adv AP) is designed to fill in the gaps of the current autopilot which are expected by our more sophisticated users. These include:

  1. Flight Director
  2. User Initiated Navigation Intercept (eg Heading to Nav capture)
  3. Vertical Navigation (both ILS Glideslope and GPS Vertical Deviation).
  4. Airspeed Hold
  5. Other stuff I can’t remember at the moment.

A goal of the adv ap is to offer complete control of the autopilot to the pilot and not make decisions for him as we do in the current autopilot (eg no heading or altitude bug syncing).

The adv ap will require additional control panel hardware. This temporary user interface is intended to mimic the control panel just enough so that the complex modes are accessible and annunciated (with minimal effort on my part). The features and user interface of the adv ap are modeled off what appears to be current industry practices in modern GA piston and jet aircraft.

Rich, hopefully it’ll work a lot like your cockpit at work. However, without a real control panel or multiple screens things will be quite cumbersome. In your single screen system you will be required to juggle 4 settings with one knob. Working without our map displayed will give you an additional knob. In the final product (with the control panel) you will adjust heading and altitude with the screen knobs (like today), but the vertical speed and airspeed targets will be controlled with a nose up/down control on the control panel.

AP Menu

The AP menu has been replaced with the following:

BACK, AP, FD, and ROL/PIT are always visible. The right-most four buttons are in two groups (roll axis and pitch axis) with only one group visible at a time.

Button Background Color (except for BACK and ROL/PIT)

Black – Off

Green – On / Active

White – Armed

BACK – Exits the AP menu.

AP – Couples / decouples the servos to the flight director.

FD – Activates / deactivates the autopilot and flight director.

ROL/PIT – Toggles which group of the right-most four buttons is visible.

ROLL – Roll Hold

Maintains the current roll target. The roll target is the current roll of the aircraft upon activation of the roll mode. If the current roll is less than 5 degrees (nearly wings level) then it is adjusted to 0 degrees (wings level). This is the default mode and will be activated if no other modes are selected upon activation of the FD.

HDG / TRK – Heading / Ground Track Hold

Maintains the current heading / ground track target. The target is always the heading bug. (This is unchanged from the modes you already know and love).

NAV – Navigation

Track the selected navigation source. (This also is unchanged).

NAV can be armed while in HDG or TRK which will maintain the current heading or track target until automatically capturing and switching to NAV mode.

VS – Vertical Speed Hold

Maintains the current vertical speed target. The vertical speed target is the current vertical speed of the aircraft upon activation of the VS mode. The target can then be adjusted via the vertical speed bug. This is the default mode and will be activated if no other modes are selected upon activation of the FD.

IAS – Airspeed Hold

Maintains the current airspeed target. The airspeed target is the current airspeed of the aircraft upon activation of the IAS mode. The target can then be adjusted via the airspeed bug.

ALT – Altitude Hold

Maintains the current altitude target. The altitude target is the current aircraft altitude upon a manual activation of altitude hold. A manual activation of the mode occurs upon pressing ALT with no other mode active, or deactivation of the active mode with ALT armed.
ALT can be armed while in VS, IAS or VNAV which will maintain the current vertical speed or airspeed target until automatically capturing and switching to the ALT mode. While ALT is armed the altitude target is the altitude bug.

Once ALT mode is active and the altitude target has been established, changing the altitude bug will not change the altitude target, thus allowing preselecting of a new altitude without causing deviation from the current altitude.

ALT will be automatically armed upon activation of VS or IAS mode if the altitude bug has been set.

VNAV – Vertical Navigation

Maintains the vertical component of the selected navigation source.

VNAV can be armed while in VS, IAS or ALT mode which will maintain the current mode and target until automatically capturing and switching to the VNAV mode. (Any time you have a glideslope indicator – ILS or GPS VDEV - this should work).

ALT mode can also be armed while in VNAV mode but there is not a separate MDA bug so you are still restricted to 100 foot increments.

Disconnect Switch – Hold to engage and control wheel steering will do nothing (for now). If the servos are engaged a single press of the disconnect switch will disconnect the servos but leave the rest of the autopilot state unchanged. With the servos disengaged a single press of the switch will turn off the autopilot entirely.

TOGA – There is no specific take-off/go-around mode. During early requirements definition it appeared that this would not be necessary. Reality may prove otherwise. I only mention it because I don’t want you to attempt to initiate the missed approach with the autopilot. At go-around time, turn off the autopilot completely with the disconnect button or the FD button, then reactivate and engage with default modes with the AP button.

PITCH – There is no specific pitch hold mode. Early thoughts on the subject are that VS is really what we want as a default mode. More practically, there is no room on the control panel.

Hold to Engaged / CWS – These features are not connected properly to the adv ap user interface. Don’t try them. The disconnect button does function as expected.

Flight Director

The flight director icon has two styles; Single Cue (shown above and is default), and Dual Cue (the horizontal and vertical cross bars).

For the single cue as shown above the entire icon is filled in magenta indicating that the servos are coupled to the autopilot. If the servos are not couple (thus the pilot is flying) the icon is hollow in the middle with a magenta outline. For the dual cue if the servos are engaged then round end-caps appear on the flight director bars.

Autopilot Status

The autopilot status is in the process of a major facelift.

The above status indicates that HDG mode (target 039 degrees) is active with LOC (ILS localizer nav) armed and ALT hold (target 2100 feet) is active with GS (ILS glideslope) armed.

The green AP and left / right arrows indicate that the servos are engaged. If the autopilot (flight director) is on without the servos engaged AP etc will be blank, but all mode annunciations and the flight director will still be available.

User Scenarios

  1. You just took off and everything is off in the ap menu and you just want the autopilot to start flying.
  2. Press AP
  3. This will turn on the autopilot and flight director in roll hold and vertical speed hold syncing both to the current state of the airplane and engage the servos.
  4. In other words, just keep doing what I’m doing.
  5. ALT will automatically armed if the altitude bug has been set once since boot. Otherwise, ALT will be armed automatically once the altitude bug has been set.
  6. You’re off and the autopilot is flying from the above step and you want to turn on course and climb to altitude.
  7. Select your heading/track with the heading bug. Remember you can hold the knob to the side to sync to the current heading.
  8. Press ROL/PIT as necessary to reveal the appropriate axes’ buttons.
  9. Press HDG
  10. HDG becomes active.
  11. Select your desired altitude with the altitude bug.
  12. Press ALT
  13. ALT becomes armed.
  14. Adjust your rate of climb with the vertical speed bug.
  15. Nobody climbs via vertical speed, you say!
  16. Press IAS
  17. IAS becomes active.
  18. If armed, ALT will remain armed otherwise it will automatically arm.
  19. The airspeed bug is sync’d to the current airspeed.
  20. Adjust your climb airspeed with the IAS bug.
  21. Enroute Navigation
  22. Setup and select your preferred navigation source.
  23. Press NAV
  24. NAV becomes armed.
  25. Adjust the heading bug for your desired intercept angle.
  26. When capture conditions are met, NAV will automatically become the active mode.
  27. I don’t want to pick an intercept, you do it, you say.
  28. With NAV armed, pressing the button of the active mode will turn off that mode, and make NAV the active mode.
  29. The autopilot will then chose an appropriate intercept as it does with the basic autopilot.
  30. Chose a new altitude with the altitude bug.
  31. The current altitude target will be preserved for the autopilot.
  32. Initiate a climb or descent to the new altitude with the VS or IAS buttons.
  33. The desired mode will become active and the target will be sync’d to the current aircraft state.
  34. Adjust the appropriate bug as necessary to effect the climb or descent at the desired performance.
  35. Again, this will be a real pain with the screen knobs. The control panel will give a dedicated interface for this.
  36. GPS or ILS Vertical Navigation
  37. If the selected nav source has a valid GSI, press VNAV to arm the VNAV mode.
  38. When capture conditions are met, VNAV will automatically become the active mode.
  39. In the same manor as NAV, if you have VNAV armed, and press the active vertical mode button it will turn off that active mode and make VNAV the active mode. This is probably not what you want, so be careful.
  40. While in VNAV mode, the altitude bug can be adjusted and ALT mode armed.