Incident Overview
On July 16, 2020, at approximately 1720 central daylight time, a Beech 36 airplane, registration N630JL, was substantially damaged when it was involved in an accident near Independence, Missouri. The pilot was not injured. The airplane was operating as a personal flight under Title 14 Code of Federal Regulations Part 91.
Previous Flight Events
The pilot recalled that during a previous flight, while cruising at 8,000 ft, the airplane began “moving back and forth.” The pilot scanned the instruments and observed that the cylinder head temperatures (CHT) for the No. 5 and No. 6 cylinders were “running in the red,” along with oil temperature. The pilot diverted to the nearest airport. During the descent for landing, the engine temperatures returned to normal, and the pilot landed uneventfully.
Decision to Return
After landing, the pilot contacted the airplane owner and discussed the situation. The owner suggested that if the pilot felt comfortable, he could return to the home airfield. Because the engine temperatures had normalized during descent and landing, the pilot agreed to attempt the return flight if the taxi and engine run-up checks were normal. The engine run-up was normal, and the pilot departed without incident.
Accident Sequence
During the initial climb, about 4 miles from the airport, the No. 4 cylinder head temperature increased significantly above the other cylinders. The pilot continued the climb, and the airplane again began moving back and forth and responded “sluggishly.” The airplane shook, and the pilot was unable to maintain altitude. He set up for a forced landing to a road. During the approach to landing, the engine quit. The pilot minimized his bank angle to avoid a stall. Upon touchdown, the pilot lost directional control, and the airplane skidded off the road into a grassy area. The airplane sustained substantial damage to the wings and fuselage.
Engine Examination
Examination of the engine revealed that the No. 5 cylinder head and piston ring had failed with signatures of detonation. Additionally, the turbocharger oil seal had failed. The pilot stated that he was not running lean of peak with fuel.
Probable Cause
No probable cause was stated in the source.