Accident Details
On August 15, 2021, at approximately 1700 central daylight time, a Cessna 150H airplane, registered as N50055, was substantially damaged during an accident near Heavener, Oklahoma. The pilot, who was the sole occupant, was not injured. The flight was conducted as a personal operation under Title 14 Code of Federal Regulations Part 91.
The pilot reported that while cruising toward his destination, the engine began to run roughly. During attempts to troubleshoot the issue, the engine stopped producing power. The pilot executed a forced landing in a field. During the landing, the airplane collided with a dirt mound and trees, resulting in substantial damage to the fuselage and wings.
Engine Examination
A postaccident examination of the engine revealed that the No. 2 cylinder exhaust valve was fractured, with associated damage present on the cylinder piston. Machining of the valve surfaces precluded a detailed analysis of the failure mode.
Maintenance History
Review of maintenance logbooks showed that the engine was last overhauled on October 17, 1988, at a tachometer time of 2,438 hours. That overhaul included replacement of the exhaust valves. The most recent inspection was a 100-hour type conducted on April 1, 2021, at a tachometer time of 3,469.17 hours. Continental Motors Service Information Letter SIL-98-9C, revised July 17, 2017, specifies time limits between major overhauls for engines in the serial number range of the accident engine: overhauls should be performed every 1,800 hours or 12 years.