Amateur/Home Built/Experimental
Flight Crew Sea; Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Rotorcraft; Flight Crew Commercial
Air Traffic Control Military 2.8; Air Traffic Control Non Radar 1.5; Air Traffic Control Radar 2.0; Flight Crew Last 90 Days 15; Flight Crew Total 4158; Flight Crew Type 94.3
Human-Machine Interface
Aircraft Equipment Problem Critical; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Loss Of Aircraft Control
Flight Crew Regained Aircraft Control; Flight Crew Returned To Clearance
Aircraft; Human Factors
I was climbing to my assigned altitude of 10;000; to expect 15;000 FT. As I was passing through 9;600 I applied left roll trim; at which point the heading servo of the autopilot disconnected abruptly; the aircraft rolled to a bank angle of 30 degrees to the left and started a left turn. Simultaneously; the altitude servo on the autopilot disconnected and the aircraft abruptly climbed.The autopilot servos on the Dynon System are designed to be overridden at 32 PSI. During autopilot operation; and while engaged; the PFD (Primary Flight Display) will display either a yellow cautionary advisory to adjust the altitude or heading trim to decrease the load [on] the autopilot [servos]. In this situation I can only surmise that the application of the roll trim (the yellow caution warning on the autopilot displayed 'slip' simultaneously with the disconnect) placed additional pressure on the heading servo; exceeding the 32 PSI; and causing a disconnect; which then caused the altitude hold servo to disconnect as well. While arresting the bank angle; heading; and altitude deviations; I noted an altimeter readout of 11;100. Upon getting the aircraft restabilized; Approach queried the deviation and I explained in abbreviated terms; apologized and stated that I had 'been busy'. I was then handed off to Center and subsequentially instructed to climb to 15;000 FT. The Turbine Legend is a relatively high performance aircraft with a high wing loading and is extremely responsive to control input. By the autopilot apparently being overridden; the aircraft responded to prior; established; trim settings.
As he was climbing to his cleared altitude of 10;000 MSL on autopilot; the pilot of a Turbine Legend Experimental aircraft was adjusting the aileron trim when the autopilot pitch and roll servos disconnected and the aircraft abruptly climbed to 11;100; rolled into a 30 degree left bank turn. The pilot recovered control and returned to his clearance.