N3508K

On June 16, 2023, at 2257 Pacific daylight time, a Piper PA-28-140, N3508K, was substantially damaged when it was involved in an accident near Rochester, Nevada. The pilot was uninjured, and the passenger received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The pilot reported he was on a cross-country flight when the engine lost power about three hours into the flight. During cruise flight at 11,500 ft mean sea level, he observed a partial loss of engine power. He said the engine rpm initially decreased from 2,400 rpm to 950 rpm, before decreasing to 450 rpm. The engine rpm continued to decay until the engine lost all power. The pilot stated he did not hear any unusual noises from the engine at the time it lost power, but he observed the fuel flow initially increase from 7.2 gallons per hour (gph) to 9 gph, before continuing to increase to 15 gph and “then above redline.” He performed the emergency checklist for loss of engine power inflight but was unable to restart the engine. He stated he could not recall if the fuel flow increased when he turned on the auxiliary fuel pump as he performed the emergency checklist.

The pilot initiated a forced landing to an area of flat terrain. During the landing, all three landing gear collapsed, which resulted in substantial damage to the right wing and fuselage. The pilot added that at the time of the accident there would have been about 30 gallons of fuel remaining on board. During recovery of the wreckage, about 15 gallons of fuel were removed from the intact left wing fuel tank, and the right wing fuel tank was breached.

The wreckage was recovered to a secure location and examined. The interior upholstery on the left side of the cockpit where the fuel selector valve was located had been removed during recovery and the fuel lines leading to the fuel selector valve had been disconnected. The fuel lines were intact from the fuel selector through both the electrical and mechanical fuel pumps. There were two Dynon Avionics fuel flow sensors installed in the fuel line immediately before the carburetor. The fuel line fitting connecting the second fuel flow sensor to the fuel line that ran to the carburetor was found broken. The carburetor was impact damaged and separated from the intake at the carburetor throat. The electrical fuel pump ran as commanded when electrical power was applied and the switch was turned on, and 2-3 oz of liquid consistent with 100LL aviation fuel was recovered. No water or contaminants were observed in the liquid. The mechanical fuel pump was removed from the engine and a small amount of liquid consistent in smell with 100 LL fuel escaped the unit when it was removed. Suction was felt on the intake side of the pump when the pump was manually operated following removal.

The engine was examined and no anomalies were noted that would have prevented the normal production of power. A Dynon EFIS-D10A unit was removed from the airframe and sent to the National Transportation Safety Board recorders laboratory. The unit did not contain any engine performance data.

The airframe and engine logbooks were not provided to investigators during the investigation and limited maintenance history was obtained.