Primary finding
Probable cause
Contamination of the airplane’s fuel system with debris, which resulted in restricted fuel flow through multiple fuel injectors and the subsequent partial loss of engine power.
Investigator assessment
Analysis narrative
The pilot reported a partial loss of engine power shortly after liftoff and performed an emergency landing on the remaining runway with the landing gear retracted, resulting in substantial damage to the airplane’s fuselage and wings. Postaccident examination of the airplane revealed that the No. 2 and No. 3 fuel injectors were obstructed by debris. Review of the airplane's maintenance records showed the fuel flow transducer was replaced on about 4 months before the accident, and the fuel injection system was cleaned just two days before the accident. Given this information, it is possible that the contamination that was found in the fuel injectors after the accident had been introduced or overlooked during recent maintenance, which ultimately resulted in a restricted fuel flow and the subsequent partial loss of engine power.
Source record
Factual narrative
On July 29, 2024, at 1210 eastern daylight time, a Raytheon Aircraft Company Bonanza A36, N934PC was substantially damaged when it was involved in an accident at Naples Municipal Airport (APF), Naples, Florida. The pilot was not injured. The flight was conducted under 14 Code of Federal Regulations Part 91 as a personal flight. The pilot reported that he conducted a preflight inspection, and the engine started and operated normally. The airplane was fueled and taxied to runway 5, where a runup was completed. The magneto check resulted in a 75 rpm drop on each magneto, and all other engine indications were normal. During the takeoff roll, engine indications remained normal. After liftoff, at approximately 150 ft above ground level, the engine began to run rough and (partially) lost power. The pilot lowered the nose and landed straight ahead on the remaining runway with the landing gear retracted. The airplane sustained buckling damage to the fuselage and wing root area. Postaccident examination of the engine revealed that the crankshaft rotated freely with compression obtained on all six cylinders. Both magnetos produced spark and were correctly timed. The spark plugs displayed normal wear, except for slight oil residue on the Nos. 2 and 4 lower plugs. The gascolator and fuel servo screens were free of debris. The fuel injectors were removed and examined. The No. 3 injector exhibited evidence of partial obstruction. After cleaning and reinstallation of all injectors, a fuel flow test revealed low flow from the No. 3 injector at high power and from the No. 5 injector at low power. The injectors were removed again for further examination, at which time the No. 2 injector was found to be nearly fully obstructed with debris. A subsequent fuel flow test with the injectors removed revealed normal fuel flow from all injector lines. Fuel samples from both main tanks were clear, light blue, and free of debris. No evidence of internal mechanical failure or ignition malfunction was identified. A review of the airplane’s maintenance records revealed that the fuel flow transducer was replaced on March 7, 2024. The records further indicated that the fuel injection system was cleaned on July 27, 2024, two days before the accident flight.