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question

MartynJF avatar image
MartynJF asked mattnischan edited

Autopilot altitude hold level off

I’ve noticed that the autopilot seems to be a bit premature in levelling off when intercepting a new altitude (e.g. climbing to a pre-selected altitude in VS or FLCH mode). That’s not coming from my own autopilot logic but the core sim autopilot logic, with the autopilot commencing the level off at as much as 1000ft before the selected altitude.

Any idea what CFG and/or PID value(s) control that?

aircraftflightmodel
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ModelMuncher avatar image
ModelMuncher answered mailman edited

Mine doesn't even attempt to level off!
Bendix King CAP140 -
Set VS mode and 1000 FPM target Alt 5000 .. it will continue climbing until its stalls
Am I missing something Obvious here ??

1 comment
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Sounds like you didn't arm the preselected altitude. There is a button in the upper right corner "ARM".

1. Set your desired altitude

2. Press "ARM"

3. Set your desired climb/descend mode (e.g. Vertical Speed)

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rhumbaflappy avatar image
rhumbaflappy answered

"Otto" the co-pilot does the same thing, and has for several updates. It seems random, and perhaps dependent on the aircraft.

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Simbol avatar image
Simbol answered Simbol commented

Have you guys adjusted the Autopilot PIDs? this is probably the cause..

S.

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We've been tweaking the PIDs but it's not clear which affect the autopilot altitude hold level-off. Do you have any experience with that?
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No much, my understanding is if the PID is too aggressive this is what happens, but I could be wrong.


Hopefully Asobo will give us some insights..

S.


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mattnischan avatar image
mattnischan answered mattnischan edited

Hi,

Right now, because the sim autopilot needs to work with a wide array of aircraft with varying performance, the altitude capture range is somewhat generous, with the following ranges:

  • FLC & PITCH - Maximum of the two: 300 feet or 30% of vertical speed in feet
  • VS - Maximum of the two: 100 feet or 33% of vertical speed in feet

These ranges are presently not configurable or influenced by PIDs. If you would like to use your own autopilot state transition logic, you can set the autopilot into AUTOPILOT AVIONICS MANAGED (which will defeat automatic altitude capture), however, you will also then need to write to all the AP state simvars as well.

Thanks,
Matt

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