Cessna 170B N1296D accident near Centralia, Washington

Probable cause

Maintenance personnel’s incorrect installation of the fuel selector valvehandle, which resulted in fuel starvation, a loss of engine power, and a forced hard landing. Contributing to the accident was the pilot's failure to follow the manufacturer's checklist.

NTSB analysis

The airline transport pilot reported that he intended to accomplish the engine manufacturer-recommended break-in procedures after repair work was completed while he was en route to another airport to fuel the airplane. The repair work had required that the fuel tanks be drained. Upon completion of the work, the recovered fuel was put in the left fuel tank. The pilot reported that he did not have an exact measurement of fuel but that he estimated that it was about 15 gallons. He also added about 6 1/4 gallons of fuel to the right fuel tank as a backup reserve. The pilot took off with the fuel selector valve (FSV) in the "left" tank position. During the climb to cruise flight, about 2,000 ft above ground level, the airplane experienced a loss of engine power. The pilot's attempts to restart the engine were unsuccessful. During the descent, the pilot switched the fuel selector to the "both" position; however, the engine would not restart. The pilot subsequently conducted a forced landing in a field; he pulled the airplane's nose up to clear some tall trees, which resulted in a stall and a subsequent hard landing in the field.

Postaccident examination of the wreckage revealed that the FSV was properly installed but that the selector handle was slightly right of the forward, or the "both," position. Further examination of the FSV handle revealed that it was incorrectly indexed to the drive shaft that coupled the handle to the FSV, which allowed the handle to be installed 180 degrees from its correct position. The observed handle orientation resulted in the FSV being closed (or off) when the FSV handle was in the "both" position, right when in the "left" position, and left when in the "right" position. The FSV was verified to be open when positioned in all three feed positions, and closed when positioned to "off."

The FSV handle had a hole drilled in it at manufacture that was angled to prevent incorrect orientation of the handle. Another hole was observed drilled through the operating arm and handle, which allowed for the incorrect installation of the handle. The investigation could not determine when this hole was drilled.

The pilot reported that, during takeoff, he believed that the fuel selector was positioned to the fuller left tank; however, due to the incorrect indexing to the drive shaft that coupled the handle to the FSV, the fuel selector was actually positioned and drawing fuel from the reserve right fuel tank, and the fuel in that tank was subsequently exhausted, which resulted in the loss of engine power. When the pilot positioned the fuel selector to the "both" position during the emergency procedures, the fuel selector valve was actually in the "off" position. The Pilot's Operating Handbook specified that the FSV should be in the "both" position during takeoff.

Text from the NTSB. Open the NTSB docket for WPR15LA153 for the full record.