C172 trainer autopilot

[spiderbuby]

Hello, I have noticed that when flying the C172 trainer, the Altitude hold does not work properly, when I activate it. The aircraft holds the current altitude, but does not move to the set altitude, I have reinstalled it, and ran the installer, but there was no change. Any help is appreciated.

-Tyler

[Oracle427]

Have you selected a vertical speed for the autopilot to use to get to the selected altitude?

By pressing the ALT button again you can select a VS mode and then use the up/down buttons to choose the desired vertical speed.

If one just selects and altitude and then presses ALT, the autopilot will simply hold the current altitude.

In addition if you chose a VS mode and don't verify that ALT mode is armed, then the autopilot will continue to climb or descend until the airplane runs out of climb performance and stalls or the airplane can't descend anymore (CFIT!).

[Nick - A2A]

Welcome to the forums Tyler.

Just to add to Oracle427's reply, you should also check you've installed the most recent Accu-Sim update for the C172, available here, even if it's a new purchase.

Vertical modes work a bit differently to the default FSX autopilot. Here's another quick summary of the basic vertical mode operation that I posted in an earlier thread:

- Once nicely trimmed on climb out, press and hold 'AP' for 0.25 seconds to engage and the autopilot will keep you climbing out at your current rate (provided the aircraft has the performance to do so).
- Turn the rotary knob(s) to select your target altitude and the autopilot will automatically arm for capture.
- Press 'UP' or 'DN' to adjust vertical speed if desired.
- Just be aware that if you preselect your target altitude (when on the ground for example), you'll need to press the 'ARM' button on the autopilot after engaging it, in order to level-off.

You may also find the following document helpful. It's a handy short intro to the KAP 140 autopilot which I found on the internet: Honeywell KAP 140 Two Axis with Altitude Preselect Autopilot

The full manual can be downloaded from another forum thread here: http://a2asimulations.com/forum/viewtop ... 07&t=35579.

Nick

[spiderbuby]

Thanks guys! I did what you said and the aircraft moved to the desired altitude.