Airways

KFC150 autopilot behaviour

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I have a question about my KFC150.  The autopilot banks rather agressively when I change the hdg. By agressively I mean it banks faster than the previous Mooney I flew (same ap).  When I command a hdg change of 30 degrees or more the ap has trouble maintaining altitude and starts a shallow descend. He corrects when exiting the turn.  Once I changed hdg by more than 90 degrees and this resulted in a vertical speed of -1500 fpm. Needless to say I disconnected the ap...

 

My question: is this behaviour a result of the autopilot computer, the servos or something else ? And is this something that can be calibrated ?

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3 hours ago, Airways said:

When I command a hdg change of 30 degrees or more the ap has trouble maintaining altitude and starts a shallow descend. He corrects when exiting the turn.  Once I changed hdg by more than 90 degrees and this resulted in a vertical speed of -1500 fpm. Needless to say I disconnected the ap...

There is a marriage of sorts between the flight director and the computer. The computer gets bank angles from fd which should be 20 degrees or so. Has anything been adjusted in that dept? Maybe attitude direction indicator been repaired or changed? When bank angles exceed ~20 degrees there will be a descent. That's normal. But the fd and computer should keep it around 20 degrees max.

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It tends to be more like 25-30 degrees which I find a lot. Is this something that can be adjusted ?

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51 minutes ago, Airways said:

It tends to be more like 25-30 degrees which I find a lot. Is this something that can be adjusted ?

Yes if it's outside the 20 degrees it should be adjusted. Best to have it looked at by an ap professional. You may want to call Autopilots Central (918) 836-6418 and run it by them.

 

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If the attitude source has been change by replacing or repairing the KI256 the gyro gains need to be adjusted.  This is done with the KTS 158 test set.  Any shop that has this test set should be able to set the bank back to 20 degrees.

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