Engine Failure and Forced Landing
The airplane lost engine power during flight, prompting a forced landing. The pilot had fueled the airplane with approximately five hours of fuel. After about four hours of flight, she contacted the tower to announce her intention to land. Shortly thereafter, the engine failed. She switched fuel tanks, which temporarily restored power, but the engine quit again. She concluded there must have been a fuel leak and radioed the tower to report the engine failure. While attempting to land at a private airport, the airplane instead touched down on a road and came to rest inverted. The forced landing involved rough terrain, causing the airplane to nosed over.
Post-Accident Inspection
No fuel was discovered at the accident scene, indicating a complete loss of fuel. A post-accident inspection identified a crack on the bottom of the elbow fitting attached to the gascolator. The gascolator is a fuel filter component in the fuel system. A Federal Aviation Administration inspector conducted a leak test using a soap-and-water solution applied under pressure. When the assembly was pressurized to between 3 and 5 pounds per square inch, bubbles formed at the crack, confirming a leak. The inspector also observed blue stains along the bottom of the airplane, consistent with fuel leakage. In the inspector's opinion, the crack was the result of excessive torque applied when tightening the fitting during previous maintenance or installation.
Conclusion
The fuel leak from the cracked fitting led to fuel exhaustion, which caused the engine to fail during flight. The pilot's attempt to reach a private airport was unsuccessful, and the airplane landed on a road, subsequently nosing over due to rough terrain. No fuel was found at the scene, supporting the finding that the fuel system leaked completely.