History of Flight
On October 11, 2023, about 1150 mountain standard time, a Piper PA-46-310P Malibu, registration N4380D, was substantially damaged during a forced landing near Chandler, Arizona. The air transport pilot and passenger were not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
The purpose of the flight was for the accident airplane to be photographed by another aircraft. The pilot reported believing there were 35 gallons of fuel onboard based on the airplane's flight logs. During the preflight, he could not visually verify the fuel quantity because the level was below the filler neck. After a normal run-up, the pilot departed runway 22R. During initial climb, about 5 miles from the departure end of the runway at approximately 1,500 ft agl, the engine experienced a partial loss of power.
The pilot declared an emergency with air traffic control and executed a 180° turn attempting to return to the airport. Unable to maintain sufficient altitude, the pilot retracted the landing gear to reduce drag. The airplane touched down in a dirt area about 500 ft short of the threshold for runway 04R, came to rest upright, and sustained damage to the left aileron.
Aircraft Information
The last maintenance was an annual inspection completed on February 08, 2023, about 52.1 hours before the accident. A fuel receipt indicated the last fueling was 16.5 gallons on September 19, 2023; the amount of fuel already in the tanks at that time is unknown. ADS-B data showed the airplane flew about 2 hours and 45 minutes over four flights since that fueling. According to the FAA, the last time the fuel tanks were topped off to full was in March 2023. Thereafter, fuel quantities could not be definitely determined, nor could fuel loss from evaporation be quantified.
Per the Pilot's Operating Handbook (POH), fuel is stored in two main integral wing tanks located outboard of the mid-wing splice. Each wing tank holds 60 usable gallons with one gallon of unusable fuel, for a total of 122 gallons. Fuel quantity is indicated by gauges located above the fuel selector handle, which operate electrically when the battery switch is on. Fuel tanks can be visually confirmed full if the level reaches the filler neck. The fuel selector determines whether the left or right auxiliary fuel pump is used, and it is not possible to draw fuel from both tanks simultaneously.
Tests and Research
The responding FAA inspector drained about 0.5 gallon from each wing tank upon arrival. With the airplane's power on, the fuel gauges indicated empty, while the JPI engine monitor showed 32 gallons remaining. Neither wing nor its fuel tank was breached; no evidence of a fuel leak or blue staining was found. The fuel selector was positioned on the “LEFT” tank.
A postaccident examination was conducted by a certified airframe and powerplant mechanic under FAA oversight. The fuel supply line was disconnected from the firewall supply line that leads to the engine-driven fuel pump. No residual fuel was observed in the line upon disconnection. A flexible extension hose was connected to the firewall line, with the opposite end placed into a five-gallon container. With the battery master switch on, the fuel quantity gauge indicated no fuel. Functional testing of the electric boost pumps confirmed operation on both high and low settings, with audible pump activity. Despite sounding functional, no fuel exited from the tanks, even during manipulation of the fuel selector. A visual inspection revealed no circuit breakers were pulled or tripped.
The sump drains were removed from both left and right collector tanks; approximately six ounces of fuel exited as the drain fittings were disconnected. No other fluid was found in the system.
The airplane was equipped with a JPI EDM-900 Primary Engine Data Management System. This system includes non-primary fuel functions requiring manual pilot input, such as “Fuel Remaining,” “Fuel Required,” and “Fuel Reserve.” The displayed 32 gallons remaining was based on pilot-entered values and was not consistent with the aircraft’s fuel quantity gauges, which indicated no fuel onboard.
A review of non-volatile memory downloaded from the JPI showed that the engine powered up to takeoff rpm at 1043:11. After two minutes of stable power indications, manifold pressure began to fluctuate with changes in exhaust gas temperatures (EGTs). Manifold pressure decreased to atmospheric pressure or below, then increased, as did the EGTs, until approximately 10:45:41. Thereafter, minor fluctuations were observed, but engine power 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—a pattern consistent with fuel starvation.