I've only had this aircraft for a few weeks (on FSX), after a bit of a learning curve I've been doing some successful flights.  This last one wasn't so successful, during the flight the landing gear lowered (at about FL370), NAV stopped directing the aircraft (went off course and had to switch NAV off & on to reset), and the autopilot master switched itself off at least five times.  At no time when all this happened was I near any of the controls.

Would the problem be the aircraft or FSX?

Thanks for looking

Any chance you had the time rate increased past 4x?

I never use rate acceleration, and for the past few flights the aircraft (or FSX) has behaved itself.  Since posting I've been checking and changing some assignments, so maybe I've unwittingly fixed the problem

Good deal