What happened
The pilot departed with an estimated 20 gallons of fuel on board and climbed to 10,000 feet for a parachute jump. Upon returning to the airport, he had approximately 10 gallons remaining. During a downwind approach, the pilot elected to execute a go-around. As the aircraft climbed through about 75 feet above ground level (AGL), the engine lost power. The pilot executed a forced landing in a small pasture.
The investigation
The accident was initially reported as an incident. However, before the official examination could take place, the wings had been removed and both the aircraft and wings were transported from the site. When investigators examined the airframe, they found that both wing tanks were empty, with the exception of a small amount of 100 low lead (blue) fuel in the right wing tank. Fluid sampled from the lines leading to the left wing tanks appeared to be automotive fuel. The owner stated that automotive fuel had been used in the aircraft previously. No fuel was found in the carburetor.
Findings
The presence of automotive fuel in the fuel system indicates contamination, which likely caused the engine power loss. The removal of wings prior to inspection compromised the ability to fully assess the mechanical state of the aircraft at the time of the accident.