Grumman G164 - B N48452 accident near Princeton, California

Probable cause

The loss of engine power during an agricultural application flight due to a cylinder failure.

NTSB analysis

The pilot reported that, during the agricultural spray run, the engine lost power. The airplane was unable to maintain altitude, so the pilot made a forced landing to a rice field. After touchdown, the airplane nosed over, which resulted in substantial damage to the rudder.

A postaccident examination of the engine revealed that the No. 2 cylinder head had cracked and lifted under the cooling fins on the cylinder's left side. The crack continued across the top and inside of the head to the intake valve seat, which would have allowed hot gases to enter the induction system and resulted in the subsequent loss of power. A review of the airplane's maintenance records revealed that a mandatory 100-hour repetitive visual inspection of the cylinder had been performed 66.7 flight hours before the accident flight.

Text from the NTSB. Open the NTSB docket for WPR15LA230 for the full record.