Inspection Findings
A post-accident inspection of the carburetor revealed a loose bellows housing on the MA-6AA carburetor's automatic mixture control. The bellows housing was found loose on the threaded tube, which remained locked to its seat, allowing the bellows to screw down onto the tube and restrict the fuel delivery orifice.
The seat and lock nut were securely bolted to the float. The last recorded carburetor repair occurred on July 22, 1993, with 817 hours of operation since that repair. Records did not specify the nature of the repair performed.
According to the carburetor manufacturer's engineering drawings, the bellows is bonded to the threaded tube using a permanent type plastic resin. The loose condition of the bellows housing contradicts the intended design specification.