N6799P

On January 16, 2025, about 1530 central standard time, a Piper PA-24 airplane, N6799P, was substantially damaged when it was involved in an accident near Bentonville, Arkansas. The pilot and the copilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 ferry flight.

The copilot reported that he just purchased the airplane and had an FAA special flight permit to ferry it to an airport for an annual inspection, which was overdue by about 5 months. The pilot, who was also an airframe and powerplant mechanic, had assisted the copilot with the prebuy inspection and completed a 100-hr inspection on the airplane.

Before the first leg of the planned three-leg ferry flight, the copilot topped off both wing fuel tanks with 29.26 gallons of 100 low lead aviation fuel, for a total of 60 gallons, with 30 gallons in each tank.

After takeoff, they climbed the airplane to 4,500 ft msl and circled above the airport to ensure the airplane was operating without issue, then proceeded west at a cruise altitude of 4,500 ft msl. The copilot’s father flew along in another airplane and received visual flight rules flight following services from air traffic control.

While en route, the pilot noted that the Nos. 3 and 4 cylinder head temperatures were higher than expected, so he did not lean the mixture. According to the copilot, about 1 hour into the first flight leg, they switched fuel tanks, planning to do so every hour. Since they did not lean the mixture and their fuel indicator showed a fuel consumption of about 20 gph, they changed their first fuel stop to an airport closer than originally planned. After landing, they topped off the tanks by adding 20 gallons of fuel to each tank and confirmed that the airplane’s fuel consumption was about 20 gph.

During the second flight leg, they selected a cruise altitude of about 6,500 ft msl and set the engine rpm about 200 rpm less than the first flight. The copilot stated that they departed with the fuel selector on the left tank and that he remembered switching to the right fuel tank during the flight. According to the pilot, he switched to the right tank about 1 hour into the flight. The pilot stated that the Nos. 3 and 4 cylinder head temperatures remained elevated, so he was unable to lean the mixture very much.

The flight was uneventful until, after descending to enter the traffic pattern at the destination airport and with the landing gear and flaps extended, the pilot adjusted the throttle, and the engine immediately lost total power. He attempted to restart the engine several times, but the starter would not engage and the propeller had stopped rotating. The copilot said that the pilot asked him to switch fuel tanks, and he switched from the right to the left fuel tank, but the engine would not restart.

The copilot stated that the airplane did not have enough altitude to make it to the runway, so the pilot executed a forced landing to a field, and the airplane came to rest upright. During the landing, the landing gear collapsed and the airplane sustained substantial damage to the fuselage and right wing.

The flight track for the copilot’s father’s airplane showed a flight time of 1 hour 44 minutes, which was just longer than the accident airplane’s flight time since he flew over the accident site to locate their forced landing position. Based on these data, the accident airplane’s flight time was about 1 hour 37 minutes.

The responding FAA inspector examined the wing fuel tanks, which remained intact, and determined that the left tank was empty, and the right tank contained about 27.5 gallons. The inspector removed a JPI EDM-700 engine data management system unit and a Shadin Microflo-L digital fuel management system unit for data extraction and analysis.

The JPI EDM-700 did not have data recording capabilities. Examination of the Shadin unit’s data revealed that the maximum usable fuel value (which is manually programmed during system setup) was set to 56 gallons. The unit displayed a fuel used value of 219 gallons and a fuel remaining value of 0.0 gallons. Per the operating manual for the Shadin unit, the system calculates the fuel remaining parameter by subtracting the fuel used value, which is tracked by the system, from the initial starting fuel value, which is manually input by the user. That is, the accuracy of the calculated fuel remaining value is dependent upon the user manually inputting the accurate initial starting fuel value at each refueling.

Postaccident examination of the engine revealed that the carburetor was impact-separated from its mounting point on the engine’s induction plenum and was resting on the lower engine cowling. The mixture lever was found halfway between full rich and idle cut-off. The mixture control cable was not attached to the mixture lever. The hardware on the mixture control arm remained installed, but it was not the correct hardware. The mixture cable moved as expected when the cockpit control was manipulated. No mechanical malfunction or anomaly other than the incorrect mixture control arm hardware was noted that would have precluded normal engine operation.

Postaccident examination of the airframe revealed that the wing fuel tanks were a type that did not retain any unusable fuel. Both fuel tanks were intact with no leaks or contaminants found. The fuel strainer bowl was removed, and the cork gasket was found intact. The bowl was void of fuel but contained a white and blue substance at the bottom of the bowl. The top white layer was hard and calcified, and the blue substance underneath was squishy and wet.

The two electric fuel boost pumps operated using the airplane’s battery power. The pump filter screens were both clear of contaminants. The pumps contained fuel, and a small amount of fuel drained from the lines at the pumps, which were the lowest point in the fuel system. The fuel selector value operated normally with no blockages or contaminants noted. No mechanical malfunction or anomaly other than the fuel strainer bowl contaminant was noted with the airframe fuel system that would have precluded normal operation.