Incident Overview
A pilot experienced an in-flight fire after takeoff and forced the airplane to land short of the runway. The preflight and engine run-up were uneventful. As the airplane climbed through 1,000 feet, the pilot observed a puff of white smoke. He decided to return to the airport, but as he neared the field, a fire erupted, prompting him to land in a field.
Maintenance History
Approximately 5.4 hours before the accident flight, the number 5 cylinder had been replaced.
Post-Accident Examination
Examination of the engine after the accident revealed that the fuel injection line for the number 5 cylinder was disconnected at the fitting of the manifold assembly, which is located below the number 3 cylinder assembly. The b-nut was off the threads of the fitting and floating along the steel fuel line. The fuel line and b-nut were visually undamaged. When reassembled, the fuel line b-nut was fitted to the manifold assembly without binding and then tightened. No other anomalies were noted.
Manufacturer Statement
The engine manufacturer's representative stated that there are no manufacturer-published torque values for the b-nut.