CEN24LA104

The pilot reported that the engine “began running very rough” while the airplane was in cruise flight about 2,500 feet mean sea level (msl). His efforts to determine the cause of the partial power loss and restore full engine power were not successful. The airport was covered in ground fog, which hindered the approach. He inadvertently landed long and attempted to execute a go-around; however, the airplane did not have sufficient power to climb and went off the end of the runway. Ground-based video depicted the airplane flying over as it neared the airport. The accompanying audio confirmed a rough running engine. Data recovered from an onboard engine monitor appeared to be stable until about 4 minutes before the accident when several cylinder exhaust gas temperatures decreased abruptly. The fuel flow and fuel pressure parameters remained stable during this time. A postrecovery engine examination was unable to identify the cause of the partial loss of engine power. Although the audio that accompanied the witness video suggested an issue with the ignition system, the postrecovery examination was unable to identify any preaccident anomalies.

On February 2, 2024, about 1042 central standard time, a Piper PA-24-260 airplane, N4284, was substantially damaged when it was involved in an accident near Cherokee, Oklahoma. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the engine “began running very rough” while in cruise flight about 2,500 feet msl. He advanced the mixture, propeller, and throttle controls full forward in an attempt to increase engine power. In addition, the pilot selected the left and right magnetos individually in an attempt to isolate an ignition system problem. However, the engine problems did not disappear during either magneto check. The fuel quantity and fuel selector position were confirmed. The pilot’s efforts to determine the cause of the partial power loss and restore full engine power were not successful. He diverted to the nearest airport; however, it was covered in ground fog, which hindered the approach. He inadvertently landed long and attempted to execute a go-around; however, the airplane did not have sufficient power to climb. The airplane went off the end of the runway, struck the airport perimeter fence, crossed a road, and impacted a second fence before coming to rest. The airframe sustained damage to both wings, the fuselage, and the empennage. Ground-based video depicted the airplane flying over as it neared the airport. The accompanying audio confirmed a rough running engine. ADS-B data depicted the airplane on a southerly course about 2,254 ft msl and 3 1/2 miles southeast of the Cherokee Municipal Airport (4O5). About 1138:20, the pilot turned right on a direct course for 4O5. The pilot subsequently entered a modified left downwind before turning final for runway 17. The final ADS-B data point was recorded at 1142:17. The airplane was over runway 17, about 1,014 ft from the departure end of the runway pavement, at an altitude of about 1,180 ft msl. The runway 17 and runway 35 arrival threshold elevations were 1,178 ft and 1,179 ft, respectively. Data recovered from an onboard engine monitor appeared to be stable until about 1038 when the exhaust gas temperature (EGT) corresponding to cylinder Nos.. 4, 5, and 6 decreased abruptly. The EGT for cylinders Nos.1 and 3 decreased but to a lesser extent. The EGT for cylinder No. 2 remained stable. The fuel flow and fuel pressure parameters remained stable until 1042. A postrecovery engine examination was unable to identify the cause of the partial loss of engine power. Internal engine and valvetrain continuity were confirmed. The spark plugs displayed normal combustion signatures. The magnetos were secure, and timing was determined to be approximately 25° before top dead center, which corresponded to the timing specified for the engine. A spark was observed across each ignition lead when the engine crankshaft was rotated. Fuel system continuity was confirmed, and the engine-driven fuel pump was operational.Engine control continuity was confirmed.