On July 5, 1996, a Cessna 210 (registration N131AC) was involved in an aviation accident near Boston, MA. Investigators recorded the probable cause as: a fracture failure of the crankcase, which resulted in separation of the number five cylinder, loss of engine power, and a ditched landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 8 related events involving the same aircraft type or operator are linked below.
During cruise at 6,000 feet, a pilot reported an engine problem and later ditched after losing all power. Examination revealed a number five cylinder separation from the crankcase, with a 3.5-inch hole.
Accident Sequence
While in cruise flight at approximately 6,000 feet, the pilot radioed that he seemed to have an engine problem, stating he was about-facing and looking at Weymouth Airport at that moment. He did not declare an emergency but indicated a need to turn around. The controller advised that a nearby airport was closed. The pilot chose to proceed to another airport and subsequently reported that the engine's oil pressure and temperature were in the right zone. Later, the pilot transmitted that there was no power and that oil was on the windshield. The airplane was unable to glide to the intended airport, and the pilot performed a ditching along the shoreline.
Examination Findings
Post-accident examination of the engine revealed that the number five cylinder had separated from the crankcase, with its mounting studs and fractured crankcase material still attached. The fracture to the crankcase resulted in a 3.5-inch hole forward of the number three cylinder. The origin of the fracture was not determined.