NTSB Identification: LAX08LA212
14 CFR Part 91: General Aviation
Accident occurred Tuesday, July 08, 2008 in Kalispell, MT
Probable Cause Approval Date: 05/12/2009
Aircraft: CESSNA 150F, registration: N8647G
Injuries: 2 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 certified flight instructor (CFI) and student took off for an instructional flight during which a series of touch-and-go landings were performed. During initial climb out for the 13th takeoff, the engine sputtered, regained power, and then lost power on the crosswind leg. The CFI took the controls and attempted a forced landing. The airplane impacted the uneven ground, collided into a fence, and was destroyed by fire. During the subsequent examination of the airframe and engine, no evidence of any preimpact mechanical malfunction was found. The engine's carburetor assembly was examined by the Safety Board Materials Laboratory. Granular material was found on the walls of the carburetor's throat and in the interior of the inlet duct. The idle jet was substantially blocked and the main jet was partially obstructed. Similar fine granular material and clumps of mixed fine and coarser granular material were also found inside the carburetor jets. Because the granular sand-like material was found in both the fuel and air sides of the carburetor, it is evident that the foreign substance entered the carburetor during flight. The airplane had a history of infrequent usage. During the 10-month period from April 2007 to February 2008, the airplane had been operated for only 8.8 hours.

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

A partial loss of engine power during initial climb due to fuel system contamination by a foreign substance. Contributing to the accident was the uneven terrain.

Full narrative available

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