Accident Overview
On April 7, 2023, at approximately 1648 central daylight time, a Cessna 182Q airplane, registration N982NC, was substantially damaged in an accident near Gardner, Kansas. The pilot and passenger were not injured. The flight was conducted as a personal flight under Title 14 Code of Federal Regulations Part 91.
Sequence of Events
The pilot reported that the flight departed New Century AirCenter Airport (IXD) in Olathe, Kansas, and was en route to Lloyd Stearman Field Airport (1K1) in Benton, Kansas. About 30 minutes into the flight, he noticed a subtle, abnormal vibration and decided to return to IXD. He stated that all engine gauges indicated normally except for a high cylinder head temperature (CHT) on one cylinder, though he could not recall which one. He adjusted the fuel mixture and successfully lowered the CHT. As the airplane descended, the engine transitioned from full power to a partial loss of power, then to total failure over approximately 30 seconds.
Forced Landing and Damage
During the subsequent forced landing, the airplane impacted a culvert and nosed over. The fuselage sustained substantial damage.
Postaccident Examination
A postaccident examination revealed that the engine could not be rotated by hand. A hole was found in the top of the engine case above the No. 6 connecting rod, and the No. 6 connecting rod had separated from the crankshaft. Upon removal of the cylinders and pistons, varying damage consistent with detonation was observed. The No. 5 piston exhibited melting on the intake side with evidence of severe detonation. Damage to the skirt of cylinder No. 6 prevented removal of its piston. All intake and exhaust valves and associated pushrods were intact with no damage noted.
Maintenance History
An interview with the mechanic who performed recent maintenance revealed that all six cylinders had been replaced with new or repaired units 90.7 flight hours before the accident. The work was performed in accordance with the Continental Overhaul Manual. The mechanic stated that no work was performed on the pistons or rings, and he had not performed a cold valve clearance check when the cylinders were installed.