Beech 35-B33 N6841Q accident near San Manuel, Arizona

Probable cause

A loss of engine power due to fuel starvation during the landing approach. Contributing to the accident was the pilot’s failure to follow the emergency checklist and switch tanks. Contributing to the severity of the pilot's injuries was the lack of a shoulder harness restraint.

NTSB analysis

The pilot overflew the airport and performed a 360-degree descending left turn to join the downwind leg for landing. As the pilot began the turn to final, the airplane's engine did not respond when he attempted to increase power. With limited time to troubleshoot, the pilot turned on the auxiliary fuel pump; the engine did not respond, and he performed a forced landing short of the runway.

The pilot intended to land at the airport to refuel. The left fuel tank quantity indicator gauge was inoperative, so he could not provide an accurate assessment of its quantity. The left fuel tank was selected during the entire approach sequence, and although 10 gallons of fuel were present in that tank after the accident, it had been breached, so an accurate assessment of the quantity before the accident could not be made. The right tank contained 12 gallons of fuel. The pilot surmised that fuel flow may have been restored if he had switched to the right fuel tank when the engine lost power, as was required by the emergency checklist.

The Pilot's Operating Handbook required that the fuel tanks contain a minimum of 10 gallons each to perform basic aerobatic maneuvers. While such maneuvers were not performed, the sweeping nature of the 360-degree descending left turn prior to landing may have forced fuel away from the tanks' supply line, resulting in fuel starvation. The engine monitor revealed that power was actually lost during that turn rather than on the base leg, further supporting this theory. Additionally, residual quantities of fuel were noted in the remaining fuel supply lines to the firewall, and no fuel was present in the lines forward of the engine driven fuel pump, bolstering the likelihood that fuel starvation occurred. A postimpact examination did not reveal any mechanical anomalies with the airframe or engine that would have precluded normal operation.

The airplane was equipped with lap belt restraints, which did not have provisions for a shoulder harness. The pilot sustained injuries to his upper body during the accident sequence, which would likely have been less severe had the airplane been equipped with either a shoulder or multi-point harness.

Text from the NTSB. Open the NTSB docket for WPR13LA190 for the full record.