Accident Overview
During the airplane's takeoff roll, witnesses reported hearing a series of repeated sounds similar to a "backfire" or "compressor stall." Several witnesses observed the right propeller stopped. As the airplane lifted off, one witness heard a loud cracking sound followed by the propeller windmilling into feather. The airplane retracted its gear, climbed, and turned right. It then pitched up, entered a "Vmc roll-over," executed a 360-degree turn, and impacted the ground.
Witness Reports
Multiple witnesses on the ground provided consistent accounts. One witness described the right propeller appearing stationary before takeoff. Another noted the loud cracking sound at liftoff and the subsequent propeller feathering. After the roll-over, the airplane descended and struck the terrain.
Radar and Flight Data
Radar data showed the airplane departed on runway heading, climbed to about 200 feet above ground level, then entered a right turn and lost altitude. The last radar return recorded a calibrated airspeed of 97 knots. According to the flight manual, the minimum controllable airspeed (Vmc) was 93 knots.
Examination of Wreckage and Engines
The accident site showed the airplane impacted in a near-vertical attitude. A post-crash fire destroyed all cockpit instruments and switches. Examination of the propellers revealed neither was feathered at impact. The left engine showed signatures consistent with operation at impact. The right engine exhibited static witness marks on the second stage impeller shroud, indicating it was not operating at impact; however, rotational scoring was also present, with static marks overlying the rotational marks. No anomalies were found that would have precluded normal operation of the right engine.
Pilot Experience
The left-seat pilot had approximately 950 total flight hours, including 16.9 hours in an MU-2 flight simulator and 4.5 hours in the accident airplane. He had begun but not completed an MU-2 pilot-initial training course. The right-seat pilot had about 2,000 total flight hours, with 20.0 hours in an MU-2 flight simulator and 20.6 hours in the accident airplane. He had successfully completed an MU-2 pilot-initial training course one month before the accident.