On February 4, 2009, about 0852 Pacific standard time, a Douglas DC-3/65AR, N834TP, collided with terrain during takeoff at Mojave, California. The National Test Pilot School was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The certified flight instructor (CFI) and the student pilot were not injured; the airplane sustained substantial damage to the fuselage and wings from impact forces. The local instructional flight was departing. Visual meteorological conditions prevailed, and no flight plan had been filed.

The operator reported that the student pilot was performing the takeoff. During the takeoff roll, the airplane began to drift to the right, and the student applied left rudder to correct for the drift. The CFI advanced the right throttle during the ground roll in an attempt to counteract the right yaw. The tail wheel came off the ground about 80 knots, and the airplane swerved to the right. The CFI applied left rudder in an attempt to stop the yaw and drift. As the airplane was about to depart the runway, the pilots did not reduce the throttles or apply brakes as they felt that it would be safer to attempt to get airborne.

The airplane slowed as it departed the runway surface. It collided with a series of berms, which sheared off the left landing gear and left engine. The right landing gear collapsed, and the airplane came to rest in a nose down attitude.

The operator stated that the student pilot inadvertently set the rudder trim to the full right position when he adjusted the rudder pedals during the prestart checks. The rudder trim was in the full right position for the takeoff, and found in the same position upon post accident inspection.