Incident Overview
The pilot of a Commander turboprop conducted a preflight inspection and prepared for takeoff from St. Paul Airport. During the takeoff roll, just as the aircraft was rotated to the takeoff attitude, the right engine failed. The pilot immediately eased the aircraft back onto the runway, reduced power, and brought it to a stop on the remaining runway surface. With the remaining engine, the pilot taxied the aircraft back to the ramp area.
Inspection Findings
Subsequent inspection of the failed engine revealed a ruptured plenum chamber, characterized by a large tear in the Inconel 718 sheet metal. A metallurgical examination of the plenum chamber identified multiple fatigue fracture areas concentrated in the welded seams.
Corrective Action
The engine was inspected further, and a serviceable plenum chamber was installed as a replacement. The engine was then returned to service.
Probable Cause
The engine failure was attributed to fatigue fractures in the welded seams of the plenum chamber, leading to a large tear and loss of engine power.