NTSB Identification: CHI07LA221.
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Accident occurred Sunday, July 22, 2007 in Moline, IL
Probable Cause Approval Date: 04/30/2008
Aircraft: Grumman G-164A, registration: N9828
Injuries: 1 Serious.

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 pilot stated that 15 minutes into the flight the airplane began to lose airspeed. The flight was 300 to 500 feet above ground level en route to the assigned spray field at the time. He noted that although he was at full throttle, the airplane continued to lose airspeed. He subsequently observed oil on the right side of the engine cowling. The pilot recalled banking left to avoid an interstate highway. He commented that the airplane "quit flying" just prior to the landing. The airplane came to rest upright in a corn field. A post impact fire consumed approximately one-half of the aircraft. A post accident inspection revealed that the number 3 engine cylinder head had separated into two sections. Examination of the fracture faces revealed features consistent with a fatigue failure. The failure initiated at the root of the cylinder head thread engaged with the uppermost barrel thread. Engine maintenance records indicated that the engine had accumulated approximately 7,495 hours total time, with about 615 hours since overhaul.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

Fatigue failure of the engine cylinder during cruise flight resulting in a loss of engine power. Additional causes were the pilot's failure to maintain sufficient airspeed and the resulting inadvertent stall during the forced landing. A contributing factor was the airplane's low altitude at the time of the loss of engine power.

Full narrative available

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