Cessna 210D N3857Y accident near Paris, Tennessee

Probable cause

The disruption of torque to the No 4 connecting rod journals, which resulted in a spun bearing and the subsequent total loss of engine power.

NTSB analysis

The pilots reported the airplane started to shake violently during cruise flight, and oil then covered the windscreen. The engine subsequently lost all power. The flight instructor took control of the airplane and performed a forced landing to a nearby airport. During the forced landing, the airplane’s main landing gear contacted the airport perimeter fence, resulting in the airplane nosing over. The airplane sustained substantial damage to both wings and the engine firewall.

Postaccident examination of the engine revealed that the No. 4 cylinder crankshaft connecting rod journals showed evidence of lubrication distress and metal transfer between the bearing and the journal. Review of the airplane’s maintenance logbooks revealed that three of the engine’s six cylinders were replaced about 3 years before the accident, with the remaining three having been replaced about 2 years before the accident. Given this information, and the condition of the No. 4 connecting rod journals, it is likely that the torque on the journals was disrupted during the cylinder replacement(s) which resulted in a spun bearing.

Text from the NTSB. Open the NTSB docket for ERA24LA095 for the full record.