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Aviation Accident

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NTSB Identification: WPR16LA082
14 CFR Part 137: Agricultural
Accident occurred Friday, March 11, 2016 in Juliaetta, ID
Probable Cause Approval Date: 05/23/2017
Aircraft: GRUMMAN G164, registration: N6894Q
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The commercial pilot was conducting an agricultural application flight. The pilot reported that, while maneuvering the airplane about 300 ft above ground level, the engine experienced a partial loss of power. Unable to maintain altitude, the pilot conducted an emergency landing to a field, during which the airplane landed hard and nosed over, coming to rest inverted. Postaccident examination of the engine revealed that the No. 2 cylinder head exhibited a circumferential crack of its barrel between the cooling fins. The Federal Aviation Administration had previously issued an airworthiness directive (AD) to address cylinder head cracking on the accident model engine. The AD required periodic visual inspections for cracks in the cylinder heads at specified intervals of time in service (every 100 hours for the accident airplane). According to the engine maintenance logbooks, the AD was last complied with about 35 hours before the accident. The previous inspections to this were sporadic, indicating that neither maintenance personnel nor the owner(s) were regularly complying with the AD.


The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
  • A partial loss of engine power¬†due to a crack in the No. 2 cylinder.¬†