Purpose Of The Flight Was For The Accident Airplane To Be Photographed By Another Pilot From A Different Airplane

Location: Chandler, Arizona Accident Number: WPR24LA012
Date & Time: October 11, 2023, 10:50 Local Registration: N4380D
Aircraft: Piper PA-46-310P Aircraft Damage: Substantial
Defining Event: Fuel exhaustion Injuries: 2 None
Flight Conducted Under: Part 91: General aviation - Personal

Analysis: The pilot stated that the purpose of the flight was for the accident airplane to be photographed by another pilot from a different airplane. The pilot stated that he believed there were 35 gallons of fuel onboard the airplane based on the airplane’s flight logs. He was unable to visually verify the actual fluid quantity in the tanks during the preflight  inspection because of the design of the tanks and the lower quantity of fuel (below the fuel filler). During the initial climb, at an altitude of about 1,500 ft above ground level (agl), the engine exhibited a partial loss of power. The pilot performed a 180° turn in an attempt to return to the airport. The airplane was unable to maintain sufficient altitude and touched down in a dirt area about 500 ft short of the runway.

Shortly after the accident, about 0.5 gallon of fuel was drained from each wing tank. The airplane’s fuel gauges indicated that the fuel tanks were empty and the engine monitor indicated that 32 gallons remained. Both wings and their respective fuel tanks were not breached; there was no evidence of a fuel leak or blue staining on the airframe. A post-accident examination revealed only trace amounts of fuel throughout the system and the boost pumps sounded to be operating normally.

The engine monitoring system requires manual input by the pilot for the “Fuel Remaining.” The displayed indication of 32 gallons remaining was based on pilot-entered values and was not consistent with the airplane’s fuel quantity gauges, which indicated that no fuel was onboard. A review of the data from the engine monitoring system revealed that following takeoff, the engine was operating normally for about two minutes. Thereafter, engine power decreased and was not restored. Fuel flow data from the transducer indicated residual flow around 2 to 3 gallons per hour, consistent with air and fuel droplets moving through the engine-driven and electric boost pumps, which is indicative of fuel starvation or exhaustion.

The last occasion the fuel tanks were topped off to full was 7-8 months before the accident and the fuel quantities thereafter could not be definitively determined, nor could the fuel loss from evaporation be quantified. Because the fuel system did not appear to be breached and only trace amounts of fuel were found in both independent fuel tanks, it is likely the fuel quantity was inadequate, resulting in air entering in the system, leading to a partial loss of power. The pilot believed the likely erroneous fuel-remaining calculations from the pilotentered fuel quantities rather than visually confirming the quantity or verifying with the airplane’s fuel gauges.

Probable Cause and Findings: The National Transportation Safety Board determines the probable cause(s) of this accident to be -- The pilot’s failure to adequately confirm the fuel quantity before departure, resulting in fuel exhaustion and a partial loss of engine power. 

FMI: www.ntsb.gov