Accident Overview
A pilot initiated takeoff on a 5,200-foot dirt runway, which was upslope to the south at an elevation of 4,775 feet. Wind was from the south at 18-20 knots, resulting in a density altitude of about 7,250 feet. Witnesses observed the aircraft taking off and saw the landing gear retract as it passed their position. Shortly thereafter, the pilot transmitted that he had 'a problem.' The aircraft was then observed at about 200-300 feet above ground level in a right turn, which progressed into a dive. The aircraft impacted in a flat attitude approximately half a mile south of runway 17. All 10 occupants were killed.
In-Flight Evidence
Passenger video recordings documented that the propellers went out of sync about 6 seconds after takeoff. Approximately 15 seconds later, the right propeller slowed until the individual blades could be seen turning. The video also showed that one engine had a fuel flow of about 90 gallons per hour (gph), while the other engine was at a minimum setting, indicated by a fuel pressure of about 3 psi. A 5-degree increase in pitch attitude was observed on the video.
Examination Findings
Post-accident examination of the right engine revealed that the driven fuel pump drive coupling was scored and only partially engaged. The aircraft had complied with Service Bulletin (SB) ME88-3. Both auxiliary fuel pump switches were found in the low position. The right propeller blades were found at fine pitch and lacked rotational damage. The landing gear was found in the up position but unlocked, and the flaps were extended to 15 degrees.
Training and Procedures
Emergency procedure training conducted by the company did not replicate conditions of high density altitude and maximum gross weight performance.
Probable Cause
Failure of the pilot to follow the emergency procedure (engine failure after takeoff) and his failure to maintain minimum control speed (VMC), which resulted in a loss of aircraft control. Factors related to the accident were failure (disengagement) of the right engine fuel pump drive coupling, high density altitude, and the lack of company training concerning aircraft performance in conditions of high density altitude and heavy gross weight.