Accident Details
On July 12, 2022, about 1000 central daylight time, a Zenith 650B airplane, registered N452VC, sustained substantial damage during an emergency landing near Eufaula, Oklahoma. The pilot and a pilot-rated passenger, both owners and builders of the aircraft, were not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal operation.
Sequence of Events
According to the pilots, while maneuvering during a local flight to adjust the airplane’s autopilot, the engine began running rough. Power continued to decrease until they could no longer maintain altitude. Unable to reach a nearby airport, the pilot flying chose to execute an off-airport emergency landing. During the landing, the airplane impacted uneven terrain, resulting in substantial damage to the right wing.
Postaccident Examination
Examination of the Corvair conversion engine revealed that the No. 5 cylinder exhaust valve rocker arm attach stud/bolt had failed. Approximately 5 flight hours before the accident, the owners had replaced the No. 5 cylinder exhaust valve, which involved removal and reinstallation of the rocker arm hardware. The push rod had an oil passage hole on one end intended for lubrication of the rocker arm, while the other end lacked such a hole. According to the owner, during installation he incorrectly positioned the push rod backward.
Damage
The right wing sustained substantial damage due to impact with uneven terrain. No other damage was reported.