Incident Overview
The aircraft was on the crosswind leg after takeoff when the pilot announced a loss of one engine and intentions to return for landing. During a left turn back toward the airport, the aircraft rolled inverted to the left and descended in a nose-down attitude until impact.
Examination Findings
Post-impact examination of the left engine carburetor revealed an extra needle valve loose in the float bowl. Another needle valve and seat assembly were correctly installed. The interior of the float bowl had numerous smooth bright spots of wear on its bottom surface, which was grainy in texture. The area around the fuel mixture metering assembly port was polished, and the loose needle valve could be inserted into that port.
Maintenance History
New engines had been installed on October 30, 1979. Records and witness accounts indicated power problems with the left engine. However, no records showed that the carburetor float bowl had ever been removed after the engine was initially installed on the aircraft.