NTSB Probable Cause

THE PILOT INADVERTENTLY MISUSED THE FLAPS, BY FAILING TO SET THE FLAPS TO THE PROPER SETTING. THE FLAPS WERE SET FULL DOWN. THIS CAUSED THE AIRCRAFT TO PITCH UP STEEPLY AFTER LIFTOFF. ADDITIONALLY, THE FLIGHT CONTROL LOCK WAS PROBABLY INSTALLED DURING SOME PORTION, IF NOT THE ENTIRE FLIGHT, WHICH PREVENTED FLIGHT CONTROL OPERATION. THE PILOT SUBSEQUENTLY FAILED TO MAINTAIN ADEQUATE FLYING SPEED AND THE AIRCRAFT STALLED. CONTRIBUTING FACTORS ARE THE PILOT'S INATTENTION AND HIS FAILURE TO ADEQUATELY USE THE CHECKLIST.