Cessna 175 N7698M accident near Skwentna, Alaska

Probable cause

The partial loss of engine power for reasons that could not be determined because the postaccident examination of the engine did not reveal any anomalies that would have precluded normal operation.

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NTSB analysis

The pilot was departing from a grass-covered runway, and about 100 feet above the ground, the airplane's engine began to lose power. Unable to maintain altitude, the pilot landed the airplane in a swamp; during the landing the airplane nosed over, substantially damaging the wings and vertical stabilizer.

The pilot stated that the engine had just been returned to service after a major overhaul, and that it had operated about 3 hours since being returned to service.

Examination of the engine revealed that the No. 6 top spark plug ignition wire was inoperative; however, it could not be determined if the damage to the wire was present before the accident. A significant amount of water was found in the gascolator bowl, but due to the position of the airplane in the swamp after the accident, it could not be determined whether or not the water was present at the time of the accident.

No other preaccident mechanical malfunctions or failures were noted that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for ANC13LA059 for the full record.