Piper PA-25-235 N8715L accident near Colquitt, Georgia

Probable cause

The failure of the fuel shutoff valve from corrosion, which allowed the valve stem to obstruct the internal fuel port, resulting in a restriction of fuel flow to the engine.

NTSB analysis

The pilot reported that preflight and ground operations were routine. Shortly after takeoff, the engine started “missing” as the airplane climbed to about 200-300 ft mean sea level. The engine speed then dropped about 50 rpm and the pilot confirmed the engine controls were fully forward before the engine lost all power. The pilot made a forced landing into a wooded swamp area. Substantial damage was confirmed to both wings and the fuselage.

Postaccident examination of the engine revealed no evidence of a preexisting malfunction or failure that would have precluded normal operation. An examination of the fuel shutoff valve from the fuel tank to the gascolator revealed that, when the valve was manipulated manually, the through-port was not totally obstructed when placed to the “closed” position. The valve arm moved back and forth with minimal resistance. The valve was then disassembled and the connection to the interior plastic gate was broken and the gate did not move when the valve stem was actuated. Further examination revealed that the two rivets that joined the stem flange to the adjacent internal component of the valve were fractured. The lower rivet failed from intergranular corrosion. The upper river showed signs of overstress in bending and shear. Once the failure occurred, the valve stem was free to move without manual input, obstructing the port and compromising fuel flow to the engine.

Text from the NTSB. Open the NTSB docket for ERA24LA248 for the full record.