Engineering & Research 415-C N99209 accident near Galion, Ohio

Probable cause

A partial loss of engine power due to an exhaust valve that was stuck in the open position.

NTSB analysis

The student pilot performed an engine run-up before departure that included a check of the magnetos and carburetor heat, noting normal rpm decreases for each. He initiated the takeoff, noting full rpm during the takeoff roll and normal takeoff distance. On the upwind leg of the airport traffic pattern, when the airplane was about 300 ft above ground level, the engine began to lose power. The pilot lowered the airplane’s nose to maintain airspeed then made a left turn to return to the airport. When the airplane was close to the airport the engine sustained a total loss of power and he realized that the airplane was too high to land on the runway. He flew over and then north of the airport, where he intended to land on an east/west oriented road. The airplane subsequently impacted a powerline pole and came to rest on the road, resulting in substantial damage to the fuselage and aft empennage.

Postaccident examination of the engine revealed the loss of engine power was a result of the No. 2 cylinder exhaust valve being stuck in the open position. About 32 years before the accident, a reconditioned cylinder was installed at the No. 2 position, there were multiple maintenance record entries associated with the No. 2 cylinder citing either a stuck exhaust valve or work to the cylinder consistent valve problems, the most recent being nearly 3 years and about 63 engine hours earlier.

Guidance from the engine manufacturer related to a stuck exhaust valve cited a need to clean the cylinder components and perform dimensional checks of specified components. It did not cite what to do for a repetitive problem.

Text from the NTSB. Open the NTSB docket for ERA22LA412 for the full record.