What happened
On January 15, 2020, a Cessna T310P, registration N5805M, was involved in a fatal accident near Roy, Utah. The aircraft was being relocated from Skypark Airport (BTF) to Ogden-Hinckley Airport (OGD) following maintenance work on the left wing-tip fuel tank.
During the flight, the aircraft's airspeed decreased from over 140 mph to under 90 mph. Witnesses near Interstate 15 observed the airplane flying at a very low altitude, approximately 150 to 200 feet above the ground, with the landing gear and flaps extended. One witness reported hearing "popping" sounds, suggesting an engine may have been attempting to restart. The aircraft was seen crabbing to the left and struggling to maintain altitude. Eventually, the left wing dropped, and the aircraft entered a steep bank to the left before the nose dropped and the plane disappeared from view.
An investigation of the crash site showed the left fuel tank struck the roof of a townhome complex, creating a debris field approximately 135 feet long. The main wreckage came to rest upright on a rock retaining wall, with the cabin area heavily damaged by fire.
The investigation
Post-accident examinations of the engines and airframe found no mechanical malfunctions that would have prevented normal operation. Analysis of the propeller blades indicated that the left engine was producing little to no power at the time of impact, and the left propeller had not been feathered, which is the standard procedure for a single-engine inoperative condition. The right engine showed evidence of operating at mid-to-low power during the impact.
Maintenance records showed that prior to the flight, only 2.5 gallons of fuel had been added to the left wing-tip tank to perform a leak check. The pilot did not refuel the aircraft before departing for the destination. A performance study determined that the aircraft was flying below its aerodynamic stall speeds as it approached the airport.
Findings
Investigators concluded that the left engine shut down during flight due to fuel exhaustion in the wing-tip tank. This loss of power caused the aircraft to yaw to the left and lose performance. The pilot failed to follow the one-engine inoperative checklist and failed to maintain the minimum controllable airspeed, leading to multiple aerodynamic stalls and the eventual loss of control.