Engine Power Loss During Post-Maintenance Check Flight
A post-maintenance check flight ended in an off-airport landing after the airplane's engine lost power. The flight was conducted after repairs to damage caused by a previous gear-up landing. Among other work, the engine had been removed, inspected, and reinstalled.
Pilot's Account
According to the pilot, soon after takeoff, while passing the departure end of the runway, the engine began losing power and running rough. He initiated a turn with the intention of landing downwind on the departure runway using the partial power available. However, during the turn, the engine ceased producing power completely. Due to low airspeed and altitude, the pilot was unable to glide to the runway and the airplane crashed in a vineyard.
Post-Accident Examination
An FAA inspector examined the engine and discovered a loose B-nut on a fuel injection system hose where the hose attached to the fuel divider on top of the engine. When the electric fuel pump was turned on, fuel sprayed from the loose B-nut. The B-nut required approximately one turn in the tightening direction to reach the snug position. No other discrepancies were noted.
Engine Test Stand Runs
The engine was removed and installed on a test stand for further evaluation. With the B-nut tightened, the engine started and ran smoothly. It was accelerated to full power and smoothly produced about 2,700 rpm. After approximately five minutes at full throttle, the B-nut was loosened. After 1/8 of a turn, fuel came out of the hose end. After 1/4 turn, the engine began to run rough. Between 1/4 and 1/2 turn, the engine abruptly stopped.