CEN24LA337

The pilot/mechanic’s improper torquing of the fuel hose fitting while replacing the fuel pump, which allowed air to enter the fuel system and resulted in a loss of engine power during initial climb. Contributing to the accident was the pilot/mechanic’s failure to detect and rectify the loose fuel hose during a subsequent annual inspection.

The pilot had flown the airplane for about an hour to practice maneuvers and then returned to the airport where he made an uneventful landing. He then taxied back to the runway for another takeoff. During the initial climb, the pilot noticed that the fuel pressure reading was dropping, but there was insufficient runway remaining to abort the takeoff. As the climb continued, the fuel pressure varied between 0 and 4 pounds per square inch (psi) and the engine surged. The pilot leveled the airplane and verified that the auxiliary electric fuel pump was on. Unable to maintain altitude, he performed a forced landing in a cornfield. The airplane incurred substantial damage to both wings, the fuselage, and the engine mount. Postaccident examination revealed that the fuel hose fitting to the suction side of the mechanical fuel pump was loose and falling off. After tightening the fitting, an engine test run was performed. (No test run was performed with the fuel hose loose.) A full-throttle engine run could not be performed due to impact-related damage to the propeller blades. However, no anomalies were detected in the engine speed range that could be achieved. The pilot, who was also a mechanic with an inspection authorization, had replaced a leaking mechanical fuel pump 16 days before the accident and had performed an annual inspection of the airplane 9 days before the accident. It is likely that the pilot/mechanic improperly torqued the fuel hose fitting during installation of the replacement fuel pump, which allowed air to enter the fuel system and resulted in a loss of engine power.

On September 2, 2024, about 1530 central daylight time, a Piper PA-28-140 airplane, N32435, was substantially damaged when it was involved in an accident near East Troy, Wisconsin. 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 before the accident flight he performed preflight and pre-takeoff checks using the checklists in the airplane owner’s handbook, with no deficiencies noted. He stated that he took off from East Troy Municipal Airport (57C), East Troy, Wisconsin, using the left fuel tank. He then proceeded to the east of 57C, where he practiced maneuvers to familiarize himself with the airplane, as it was his first time operating it outside the traffic pattern. During this time, he switched the fuel selector to the right fuel tank. He stated that he noticed small changes in the fuel pressure reading—about 1 psi variation—but was not concerned because it remained in the normal operating range of 0.5–8 psi. After about an hour of flight, the pilot returned to 57C and performed a full-stop landing. After taxiing back for another takeoff, he checked all of the engine gauges, including fuel pressure with and without the auxiliary electric pump activated. He noticed that the fuel pressure was about 1 psi lower with the auxiliary pump turned off but still within the normal operating range. He performed the pre-takeoff checks, switched back to the left (fullest) fuel tank, and proceeded to take off. During the initial climb, the pilot noticed that the fuel pressure reading was dropping, but there was insufficient runway remaining to abort the takeoff. As the climb continued, the fuel pressure varied between 0 and 4 psi and the engine surged. The pilot leveled the airplane and verified that the auxiliary electric fuel pump was on. Unable to maintain altitude, he performed a forced landing in a cornfield. The pilot reported that the airplane received damage to the nose landing gear, engine mount, forward fuselage, both wing spars, the left fuselage due to wing impact, and the fuselage-wing attachment structure. Postaccident examination of the airplane after its removal from the accident site revealed that the fuel hose fitting to the suction side of the mechanical fuel pump was loose, and the hose was almost falling off. After tightening the fitting, an engine test run was performed. (No test run was performed with the fuel hose loose.) The propeller blades were bent, which prevented a full-throttle test, but no anomalies were detected in the engine speed range that could be achieved. Maintenance records showed that the pilot, who was also a mechanic with an inspection authorization, had replaced a leaking mechanical fuel pump on August 17, 2024, and he had completed the airplane’s annual inspection on August 24, 2024.