Engine Power Loss During Takeoff Leads to Forced Landing and Ground Impact (N99KJ)

Accident Sequence

The airplane lost engine power during takeoff from a private airstrip and collided with the ground during the ensuing forced landing attempt. During the initial takeoff climb, at approximately 1,000 feet above ground level, the engine sputtered. The pilot changed the fuel tank selector from the "BOTH" position to the "RIGHT" position and adjusted the mixture control. Partial power returned momentarily; shortly thereafter, the engine lost power again. During the forced landing on uneven terrain, the right wing impacted the ground.

Post-Accident Examination

Post-accident examination revealed that the left muffler's exhaust stack was detached from the manifold. The exhaust stack is secured to the exhaust manifold outlet tube with a pin. This pin was eroded and no longer secured the two pieces together. Evidence of heat was found on the fuel lines and plastic tubing in the area of the exhaust stack. According to the AC 65-12A, vapor lock can be induced by high fuel temperatures and result in a partial or complete loss of power. A post-accident test run of the engine did not reveal any operating anomalies or malfunctions.