NTSB Identification: WPR10LA122
14 CFR Part 91: General Aviation
Accident occurred Saturday, January 30, 2010 in Pullman, WA
Probable Cause Approval Date: 07/15/2010
Aircraft: GRUMMAN ACFT ENG COR-SCHWEIZER G-164B, registration: N6799K
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.

Due to the cold temperatures on the morning of the flight, the pilot followed the “Cold Weather Engine Operation” procedures in the Ag-Cat pilot handbook. Because those procedures called for the engine oil and cylinder head temperatures to reach a minimum level before takeoff, the pilot had run the engine on the ground for about 30 minutes prior to performing the pre-takeoff run-up check. During that check he exercised the carburetor heat system, which worked as prescribed. During the long run-up, a bird’s nest became dislodged and was sucked into the area near the carburetor inlet screen during the carburetor heat test. The condition of the nest remains indicated that during the increased volume and velocity air flow during takeoff, the nest partially disintegrated and ultimately covered a significant portion of the inlet screen surface. According to the Federal Aviation Administration inspector who monitored the engine inspection, the nest was located inside the warm air pick-up ducting, which is an area that the pilot would not normally see into or check unless there was external visual evidence to indicate the need for a further inspection.

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

A partial loss of engine power during takeoff due to a bird's nest being sucked into the induction air ducting.

Full narrative available

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