WPR20CA112 · De Havilland DHC6 300

An operator's pilot was conducting training for a newly hired pilot for a first officer position in the twin-engine airplane. After accomplishing air work, the pilots returned to the airport to practice landings and takeoffs. According to both pilots, the first approach was normal, and the airplane touched down slightly right of the runway centerline. The trainee pilot stated that, after touchdown, the airplane began drifting further right and that he was unable to correct the deviation. The trainer pilot reported that, when directional control became unstable, he told the trainee, "I have the controls." The trainer pilot saw that the trainee pilot released his hands from the engine power levers and the yoke, but the airplane continued to deviate to the right, contrary to his control inputs and his addition of asymmetric power to the engines. The trainer pilot realized that, based on his inputs, the airplane should have returned to the centerline but that it did not and that it was behaving as if the trainee pilot was applying some braking. At that point, the trainer pilot again told the trainee pilot to release the controls, and he used the brakes, which he reported applied and released normally. Subsequently, the airplane exited the right side of the runway and impacted a ditch. The airplane sustained substantial damage to the right wing. The trainer pilot and the operator reported that there were no mechanical failures or malfunctions with the airplane that would have precluded normal operation. The trainer pilot reported that he believed the trainee pilot's feet were either on the brakes or interfered with his brake and/or rudder application attempts. The trainee pilot reported that he could not recall the position of his feet after he relinquished airplane control to the trainer pilot.

Verbatim NTSB analysis and probable cause from the NTSB dataset