Incident Overview
A pilot decided to divert to an alternate airport for fuel after the flight took longer than anticipated. While being vectored for an approach, the engine stopped. During the subsequent forced landing, the airplane collided with trees and the ground.
Investigation Findings
Investigators found no evidence of fuel loss during the flight or at the accident site. The engine was operated after the accident. However, testing of the fuel injector servo revealed that its flow exceeded the maximum limit specified by the manufacturer.
Fuel Consumption Analysis
The pilot stated he used 11 gallons per hour (gph) for fuel usage planning. According to the engine manufacturer's operating manual, at the power setting and altitude reported by the pilot, fuel consumption would be between 11.3 and 13 gph, depending on the mixture setting. Based on the elapsed flight time, the usable fuel supply in the airplane, and the excessive fuel servo flow, at 11.3 gph about six gallons of fuel would have remained in the airplane. At 13 gph, more fuel than the usable capacity would have been required. Thus, the actual fuel usage exceeded the pilot's planned usage, discounting the servo's excessive flow rate.