NTSB Identification: LAX06LA265.
The docket is stored in the Docket Management System (DMS). Please contact Records Management Division
Accident occurred Friday, August 18, 2006 in Red Bluff, CA
Probable Cause Approval Date: 12/20/2007
Aircraft: Cessna A150M, registration: C-GOBC
Injuries: 1 Minor.

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 airplane experienced a loss of engine power after takeoff, made a forced landing, touched down on uneven terrain, and came to rest inverted. The pilot was on the fourth leg of a cross-country flight when the engine lost power on the initial climb-out about 200 feet agl. Investigators inspected the engine and found the exhaust valves for two of the cylinders stuck in the open position, with dark combustion deposits in the combustion chambers. Both of the exhaust valves exhibited purple discoloration consistent with thermal overheating damage. All four cylinders exhibited pink discoloration of the head and cooling fins in the vicinity of the exhaust ports, which is consistent with thermal overheating. The pilot reported that the engine had been running rough during the approach phase of the flight prior to the accident. The pilot flew the airplane a total distance of approximately 567 nm on the day of the accident. The previous 19.8 hours of the airplane were flown exclusively by the accident pilot. Just prior to the accident, the engine had undergone a 50-hour inspection, and had had a major overhaul 185 hours ago.

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

The pilot's improper mixture leaning technique, which lead to thermal damage and seizure of the exhaust valves.

Full narrative available

Index for Aug2006 | Index of months