Accident Summary
The pilot had just departed the runway when he reported to the flight service station that he had engine problems. The aircraft was observed by witnesses to be about 300 feet on a descending downwind. The pilot stated that he was circling for runway 01. Surviving passengers described the engines as running rough and uneven. The aircraft subsequently collided with trees and a residence. The pilot and five passengers were killed; two other passengers and two people on the ground were injured.
Investigation Findings
Weight and Balance
The investigation revealed that the aircraft's weight was more than the pilot had calculated and the center of gravity (CofG) was 3.4 inches further aft than was calculated. However, the weight and CofG were within limits.
Engine Examination
Examination of the engine disclosed that the right engine had an extensive cylinder head crack, a partially disconnected intake pipe, and was capable of producing 55% of rated power. The left engine had seven severely worn cam lobes.
Flight Controls
The rudder trim was deflected full left at impact. The evidence indicated that the pilot had retarded the throttle for the left engine and was using only the right engine to sustain flight.
Company Procedures
Examination of company checklist usage revealed several different improper versions.
Probable Cause
The probable cause, as determined by the official investigation, includes a loss of engine power (partial) due to mechanical failure/malfunction during takeoff initial climb (right engine cylinder failure and intake manifold separation, left engine camshaft wear from inadequate maintenance), and a subsequent loss of engine power during maneuvering due to the pilot-in-command's improper emergency procedures (improper use of throttle/power control) and improper trim setting.