WPR23LA201

A partial loss of engine power due to restricted fuel flow resulting from foreign object debris in the fuel flow transducer.

The pilot reported that the accident flight was the first flight after an engine overhaul had been completed the pilot departed from the runway after conducting initial engine break-in procedures on the ground. The last ground break-in procedure called for the pilot to apply full power for 5 seconds. During this task, the airplane jumped the chocks before reaching the 5-second mark, so the pilot shut down the engine and the engine ground runup break-in procedure was not completed. During the initial climb, the pilot informed the tower controller that the airplane was not achieving the climb-out performance needed and requested a 180° turn back to the runway. The pilot initiated a left turn; however, the airplane impacted the ground in a left-wing-low and nose-low attitude about 2,085 ft east of the departure end of the runway. Postaccident examination of the airplane’s engine revealed no evidence of preimpact mechanical malfunction. Examination of the air induction and exhaust systems revealed no evidence of preimpact mechanical malfunction or failure. However, examination of the fuel flow transducer revealed a 5/8” x 1/4” polymer strip inside of the fuel entry port bore. The airplane was equipped with an engine data monitor. Postaccident examination of the accident flight engine data revealed that the engine rpm decreased, the exhaust gas temperature and cylinder head temperature increased, and the fuel flow gradually decreased throughout the flight. The foreign object in the fuel flow transducer, likely resulted in a fuel flow restriction and partial loss of engine power. The engine logbook revealed that all fluid carrying flexible hoses were replaced prior to initiating engine break in procedures, and it is likely that the foreign object found in the fuel flow transducer was introduced to the fuel system during installation of the fuel carrying flexible hoses.

On May 24, 2023, about 0940 mountain standard time, a Cessna 177B, N34713, was substantially damaged when it was involved in an accident near Tucson, Arizona. The pilot sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the accident flight was the first flight after an engine overhaul had been completed. The morning of the accident, he boarded the airplane at Tucson International Airport (TUS), Tucson, Arizona, and initiated an engine break in, beginning with ground operational tests. The last task in the ground operational test procedure called for a 5-second full-power application. During this power application, the airplane’s tires rolled beyond the wheel chocks; the engine was shut down and the task was not repeated. Subsequently, the pilot restarted the engine, contacted the tower controller, and requested a visual flight rules departure, with the intention to perform in-flight engine break-in procedures. The pilot recalled that the takeoff roll and rotation were normal, but during the initial climb, the airplane did not maintain the expected climb profile. While flying over the departure end of the runway, he informed the tower controller that he needed to make a 180° turn and return to the runway. The pilot was cleared as requested by the tower controller. The pilot initiated a left turn; however, the airplane descended and impacted the ground. The accident site was located about 2,085 ft east of the departure end of runway 11L, on a heading of 109° magnetic from the threshold. Postaccident photographs of the accident airplane indicated that the airplane’s left wing impacted the ground in a nose-low attitude. The outboard left wing separated at the aileron/flap junction and exhibited crushing signatures from the bottom, emanating to the leading edge of the remaining wing structure. The corresponding damage to the outboard leading edge of the right wing and aileron was consistent with a postimpact cartwheel motion. The empennage was separated from the fuselage aft of the baggage compartment. The cabin roof remained attached to the right wing and the inboard left wing. The instrument panel, engine, and nose strut were observed as one unit. Postaccident examination of the airplane’s engine revealed no evidence of preimpact mechanical malfunctions. Examination of the induction and exhaust systems revealed no evidence of preimpact mechanical malfunction or failure. Examination of the electrical system revealed that the right and left magnetos remained securely affixed to their respective mounting pads. The ignition harness was secure at each magneto. Magneto-to-engine timing could not be ascertained due to the destruction of the flywheel; however, both magnetos were timed within 1° of each other. The magnetos were removed for examination. The right magneto produced spark at the end of each respective spark plug lead during hand rotation of the drive. The drives of each magneto remained intact and undamaged. The impulse coupler of the left magneto was not functioning during hand rotation of the drive. The pawl was not engaging the pin. A review of the airplane’s engine logbook indicated that all fluid carrying flexible hoses were replaced before the engine break-in procedures were initiated. Examination of the fuel system revealed no anomalies from the left-and right-wing tanks to the auxiliary feeder tank through the fuel selector. Continuity was observed from the fuel selector to the gascolator. A small amount of fuel was drained from the fuel strainer, which tested negative for water contamination using Sar-Gel water/phase separation indicating paste. Compressed air was introduced to the left-and right-tank fuel pick-up lines to verify that there were no obstructions from the fuel tanks to the engine-driven fuel pump inlet line. A small amount of dirt was found in the fuel strainer bowl. The fuel flow transducer exhibited a fuel flow restriction that limited the quantity of fuel delivered to the carburetor. The carburetor was removed, disassembled, and was unremarkable. Further examination of the fuel flow transducer was conducted to identify the fuel flow restriction. The Electronics International Inc. FT-60 fuel flow transducer was removed and disassembled. The examination revealed that the rotor was unremarkable; however, inside the transducer there was a 5/8” x 1/4” polymer strip inside of the fuel entry port bore. The airplane was equipped with an Electronics International Inc. CGR-30P engine monitor. Examination of the accident flight data revealed at 09:36:03, the engine rpm increased to 1,550 rpm and continued to increase, reaching a maximum of 2,700 rpm at 09:36:13. At 2,700 rpm the data indicated that the engine horsepower was 84%, but decreased to 75% during the initial climb. Additionally, during the initial climb, the exhaust gas temperatures were high, and per the manufacturer’s pilot operating handbook, the cylinder head temperature increased beyond the maximum limitation of 500° F. Furthermore, during the initial climb, the maximum fuel flow reached 16.9 gallons per hour and a variable decrease was observed through the remainder of the flight. The data also revealed that the airplane’s maximum altitude during the accident flight was 101 ft above ground level (agl). The engine monitor did not record flight data after 09:38:16. The airplane’s altitude during this time stamp was 96 ft agl.