When parked, with parking breaks on and chocks on (and engines off), the aircraft will be randomly, bu repeteadly moved backwards (by wind?) inch by inch. Would anyone know what can be the cause? Is this a bug or a feature unknown to the user (me)? 
Jacek
Iāve only seen this behavior with parking break off when reverse thrust is accidentally set.
It shouldnāt. Does it do it all the time, or just happened the once?
Engage the āIdle On Platformā lever, otherwise, the reverse thrust will work and the plane will move backwards.
Also, when landing: if the lever is not engaged, the reverse thrust will work and the plane might even ānose upā when going in reverse!
Lever is marked with a yellow circle and push to engage:
It actually happens every time, even right after loading the sim and aircraft in ācold & darkā state. As if wind gusts were slowly moving the aircraft backwards.
@ArchBlizzard278 Hah, checked it twice - parking brake was / is on when this happens. 
@Dutch1957 The lever is in proper position for parking (i.e. pulled on ground), and propeller is feathered. Please note that engines are OFF, hence no reverse thrust is being generated. The aircraft is moving even when ācold & darkā.
Ive got the same issue, seems like the wind is pushing the plane back, tried everything you guys mentioned but still same issueā¦
Got it to. Just found out fsrealistic wind ambience is causing this. Tune it down to about 13 and it should be better.
