Accident Sequence
A pilot departed with an auxiliary fuel tank system installed and filled. Minutes into the flight, fuel was observed on the cabin floor. The pilot attempted to reach an airport but the intensity of fuel fumes prompted a decision to land in an open field. After touchdown, the airplane traversed a ditch that was not visible from the air. The nose landing gear collapsed and the airplane nosed over.
An airborne witness reported that the pilot exited the airplane approximately five minutes after the accident sequence. About five minutes later, the airplane caught fire and was consumed by the post-crash fire, which destroyed the cabin.
Pilot Report and Investigation
During an interview, the pilot stated that he had not activated the auxiliary fuel tank system at the time of the accident. He also reported being unable to identify the source of the fuel leak.
The investigation revealed that the auxiliary fuel tank installation did not match the approved FAA Form 337. The instructions provided for use of the ferry tank system were deemed inadequate. Additionally, the auxiliary fuel pumps were secured to a board that was not fastened to the airplane structure.
Probable Cause
The probable cause of the accident was an inadequate auxiliary fuel tank installation, which resulted in a fuel leak of undetermined origin.