What happened
Shortly after liftoff, the pilot experienced an unexpected yaw to the left and observed that the manifold pressure on the right engine had dropped significantly from 42 inches of mercury to 29 inches. Suspecting a turbocharger failure, the pilot decided to keep the engine running in a normally aspirated mode rather than shutting it down immediately. At an altitude of approximately 400 feet, smoke and fire became visible emanating from the right side of the engine compartment. The pilot promptly secured and feathered the affected engine and proceeded to make a safe single-engine landing.
The investigation
Post-accident examination revealed that the common exhaust pipe connecting cylinders #1, #3, and #5 to the turbocharger had separated. This failure allowed hot exhaust gases to impinge directly on the engine compartment, burning through the cowl and severing several electrical wires. The detached component had been replaced just 1.5 hours prior to the incident. Investigation determined that a wrong replacement part was used; it was shorter than the required specification but could be installed due to overlapping exhaust tube slip joints.
Findings
The maintenance facility cited poor organization and numbering of parts catalogs as contributing factors to the installation error. The use of an incorrect, shorter part allowed for improper assembly that ultimately failed under operational stress.
Safety message
Strict adherence to parts specifications and improved catalog organization are critical to preventing maintenance errors that can lead to catastrophic in-flight failures.