Corona, CA, USA
N841AD
PIPER PA-32-300
The pilot reported that the engine lost partial power when he adjusted the engine power while entering the downwind leg of the traffic pattern. The engine did not respond, so he cycled the throttle several times with no change. Unable to maintain altitude, he initiated a forced landing onto a freeway, during which the airplane impacted a freeway barrier and a postaccident fire ensued that resulted in substantial damage. The pilot further reported that he did not believe he turned on the auxiliary fuel pump switch before the accident. Examination of the airframe and engine revealed that the fuel supply line from the engine driven fuel pump to the fuel servo had a torsional twist near the engine driven fuel pump outlet port. The engine-driven fuel pump was removed and exhibited signatures consistent with a preexisting fuel leak at the case split, along with corrosion to the input drive seal area. The pump was tested utilizing a test bench, the fuel pump output pressure was found to be within manufacturer limits despite the preexisting leak and likely did not contribute to a loss of engine power. It could not be determined how much the kinked fuel line restricted the fuel flow to the fuel servo. Downloaded engine monitoring data showed that fuel flow was within the manufacturers specified limits, thus it’s likely that the twisted fuel line did not contribute to the loss of engine power. The loss of engine power could not be determined due to the available evidence.
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
The airplane’s partial loss of engine power during the landing for reasons that could not be determined based on the available evidence, which resulted in an off airport landing and subsequent fire.
Source: NTSB Aviation Accident Database
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