Overview
An aircraft experienced an engine failure shortly after smoke began accumulating in the cabin during climbout. Ground witnesses observed smoke emanating from the engine compartment just before the aircraft collided with a large woodpile located behind a house approximately half a mile east of the airport.
Examination Findings
Post-accident examination disclosed that the left intermediate exhaust pipe, a 90-degree elbow, had separated from the exhaust crossover tube that leads to the turbocharger. This separation allowed intense, hot exhaust gases to flow directly from the elbow into the engine compartment. The flange at the opposite end of the elbow was found to be cracked. Evidence indicated that the gasket, as well as the flanges, had been misaligned. A repair to the exhaust system had been performed approximately one month before the accident.
Sequence of Events
During the climbout phase, smoke began filling the cabin, and shortly thereafter the engine(s) stopped. Witnesses on the ground reported seeing smoke coming from the engine compartment moments before the aircraft struck the woodpile. The aircraft came to rest at the accident site, located east of the airport.
Mechanical Details
The exhaust system failure involved a critical component: the left intermediate exhaust pipe elbow. The separation at the crossover tube junction created a path for hot gases to escape into the engine compartment, likely contributing to the smoke observed. The cracked flange and misalignment of the gasket and flanges suggest improper installation or maintenance issues from the prior repair.