N841AD

On August 9, 2022, about 1231 Pacific daylight time, a Piper, PA-32-300, N841AD, was substantially damaged when it was involved in an accident near Corona, California. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The flight departed Corona Municipal Airport (AJO) about 1115 for a local flight. The pilot reported that they were returning to AJO when he adjusted the engine power to level off and reduce airspeed while entering the downwind leg of the traffic. He stated that the engine did not respond, and he cycled the throttle several times with no change. The airplane was unable to maintain altitude and the pilot elected to make a forced landing onto the eastbound lanes of US Highway91. During the landing flare, to prevent the airplane from impacting a car, the pilot intentionally stalled the airplane. The airplane landed hard, rotated to the right (clockwise), and impacted a freeway barrier. He and the passenger exited the airplane and a postaccident fire ensued.

The pilot reported that he normally verifies that the auxiliary fuel pump selector switch is in the on position before entering the downwind leg of the traffic pattern, when he completes a pre-landing checklist. He said he did not think he turned on the fuel boost pump switch as he entered the traffic pattern because he was responding to the loss of engine power and finding a suitable area for an emergency landing.

Postaccident examination of the airplane revealed that the cockpit and fuselage was mostly destroyed by thermal and impact damage. Throttle and mixture control continuity was established from the cockpit controls to the fuel servo and moved from stop to stop when actuated by hand. A visual inspection of the fuel system established continuity from the wing roots to the fuel injectors. Various breaks in the wing fuel lines were observed in both wings, consistent with cuts by recovery personnel and/or impact damage. A torsional twist (kink) in the steel braided fuel supply output line from the engine driven fuel pump to the fuel servo was observed. There was no visible impact damage to the airframe that would account for the torsional twist in the fuel line. The position of the auxiliary fuel pump switch could not be determined due to fire damage.

A subsequent examination of the engine driven fuel pump revealed evidence of a preexisting fuel leak at the case split, along with corrosion to the input drive seal area. The fuel pump was connected to a test stand and the pump was able to maintain and exceed output fuel pressure at idle and high speeds. Furthermore, the pump was found to be within limits when the kinked output fuel line was installed; however, as the fuel line B-nuts were progressively torqued utilizing a hand tool, the pump pressure decreased until it was no longer able to maintain adequate output pressure.

The airplane was equipped with a J. P. Instruments EDM-830 engine monitor. The engine monitor was removed at sent to the National Transportation Safety Board Vehicle Recorder Laboratory. Examination of the engine monitor revealed heat and fire damaged to the exterior of the unit. The non-volatile memory chip was removed, installed on a functional lab surrogate unit, and data were downloaded normally using the manufacturer’s procedures. The recorded time and the time displayed is from 17:25:00 to 19:30:00. Throughout the recorded data, changes in engine rpm, fuel flow, manifold pressure, horsepower, oil pressure and oil temperature were observed consistent with takeoff, climbs, and descent power settings. At about 19:22 a reduction of manifold pressure, engine rpm and fuel flow were observed. The data shows that at 19:23:36 the fuel flow indicated from 24.4 gallons an hour, the manifold pressure indicated 26.4 and the engine rpm indicated 2502. The subsequent data showed the manifold pressure increased to 30.1, a decrease in engine rpm to 80 and fuel flow variation from 0 gallons an hour to 3.2 gallons an hour.

A review of the airplane’s maintenance records showed that the fuel servo had been replaced on February 20, 2019, and did not reveal if any subsequent maintenance had been performed on the engine-driven fuel pump or kinked fuel line.

Figure: View of fuel line without the protective outer cover