D10A Heading doing "S-lines", unable to stabilize after numerous calibrations


New Member
Jun 20, 2020

I would like to get help about my HDG problems with the D10A equipped a with remote compass and coupled to an AP74 (aircraft is an FK9 ULM). The GPS Garmin 296 is correctely set and NAV mode is working with only small corrections, same with TRK mode.
HDG mode is a mess and there is no way to fly without S-lines between -15 and +15 degrees.
Since I bought the FK9 2 years ago I am still fighting with the HDG problem, after numerous calibrations on ground and in flight, correct MAGINT and MAGINC set and despite I follow all the procedures according to the installation manual there is no way to resolve the "S-lines" of the EFIS HDG.
I changed the remote compass, the AILERON servo (from a SV42 to a SV52) thinking this was the problem.
My last idea is now to think about sending the D10A into repair (which is quite expensive) or buy a new one....
A few friends told me that it'cant be the D10A because it gets it´s HDG informations from the remote compass.
Did anyone experience similar problems or could anyone give me a last hint or solution?
I will try a last calibration with all electrical equipment of (except the radio) and do a flight like that to see what will happen.

Thanks for help and best regards,


Brent Dana

Aug 23, 2020
Suggestion: look at where your magnatometer is? Is it in close proximity to something that is magnetized or affected by a magnetic field and therefor causing the drift, as would a compass in the same situation. Adahar, could be affected too. That is why is is recommended to be put in the tail. Sounds like the issue to me, something is interferring with the precise instrument.