Piper PA-24-250 N8233P accident near Westbrook, Connecticut

Probable cause

A total loss of engine power during approach due to inadequate torque on the No. 3 cylinder hold-down nuts.

NTSB analysis

During approach to the destination airport, the airplane experienced a loss of engine oil pressure followed by a total loss of engine power. The airplane subsequently impacted wooded terrain about 3 miles from the runway. Examination of the engine revealed that the No. 3 cylinder had separated from the engine case, and its hold-down nuts were not recovered. The hold-down nuts for the adjacent No. 5 cylinder were loose and not adequately torqued to the extent that, had the engine continued to operate, the No. 5 cylinder would have separated. No other mechanical failures were noted with the engine. The Nos. 3 and 5 cylinders, which were newer than the other cylinders and were manufactured by a different company than the original engine manufacturer, were installed about 13 years prior to the accident. There was no record of any recent work performed on those cylinders, and the most recent annual inspection was completed 10 months prior to the accident. Based on the available evidence, the No. 3 cylinder separation was likely due to inadequate torquing of the cylinder hold-down nuts.

Text from the NTSB. Open the NTSB docket for ERA11FA334 for the full record.