Narrative
The pilot and co-owner arrived at the airport to retrieve the airplane. The co-owner noticed that the left wing was lower than the right wing and fuel was draining from the fuel vent. The pilot moved the fuel selector valve from the "Both" position to the right main fuel tank position. The pilot then opened the left main fuel cap and reported that the left main fuel tank was full. The co-owner opened the right main fuel cap and estimated that about six gallons of fuel were present.
The pilot started the engine, taxied to the run-up area, completed the engine run, and departed. During the right crosswind turn at an altitude of about 50 feet, the engine lost power. The pilot lowered the nose and attempted to move the fuel selector valve from the right tank position to the left main fuel tank position, but the attempt was unsuccessful. The engine briefly started and then stopped. The pilot executed a forced landing straight ahead into trees.
Examination
Post-accident examination revealed that the left and right main fuel tanks were not ruptured. No fuel was present in the left main fuel tank, while five gallons of fuel were removed from the right main fuel tank by recovery personnel. No fuel leakage was observed on the ground. The airplane was recovered to a storage facility. Each main fuel tank has a capacity of 18 gallons, of which 1.5 gallons are not usable during non-level flight. Both tanks were found to contain water, and there was no evidence of leakage. When shop air was applied to the fuel system, no anomalies were noted.
Post-Accident Engine Testing
The investigation revealed that plumbing for an external fuel source had been connected into the left and right fuel tank supply lines using a flexible hose for two engine runs. For the first engine run, the fuel selector valve was placed in the left main fuel selector position; for the second, in the right main fuel selector position. During each run, the engine was started, the throttle advanced to 1,000 rpm and stabilized for two minutes, then advanced to 1,500 rpm for a magneto check, followed by 2,200 rpm stabilized for five minutes. The engine was then returned to idle and shut down. No anomalies were observed during either engine run.