Cessna TU206G N6169Z accident near Puyallup, Washington

Probable cause

The pilots’ activation of the fuel boost pump while preparing to land, which was contrary to checklist procedures and resulted in a loss of engine power.

NTSB analysis

The airplane was on the downwind leg of the traffic pattern during an instructional flight, and the pilots performed the prelanding checklist, switched the fuel selector to the right tank position, and activated the fuel boost pump. According to the flight instructor, the airplane “began sinking” while on final approach for the runway. When the pilots tried to add engine power, the engine did not respond, and the airplane collided with terrain short of the runway. The manufacturer’s approved checklist for the airplane indicates that the auxiliary fuel boost pump should be in the off position before landing. A representative from the engine manufacturer reported that operating the auxiliary fuel boost pump at a low engine power setting would “flood” the engine and result in a loss of engine power. It is likely that when the pilots applied power, the engine was flooded, which resulted in the total loss of engine power. Postaccident examination of the airframe and engine revealed no preaccident mechanical malfunctions or failures that would have precluded engine operations.

Text from the NTSB. Open the NTSB docket for WPR11LA168 for the full record.