What happened
On October 23, 2009, a Daher SOCATA TB 10 Tobago, registered F-GBHO, was performing a maintenance test flight at the Saint-Cyr-l’Ecole aerodrome. Following a series of successful ground engine runs with no observed anomalies, the pilot initiated a takeoff from runway 29 L.
During the takeoff roll, the engine failed to deliver full power. Recognizing the performance deficiency, the pilot elected to abort the takeoff. While attempting to land back on the runway, the aircraft exited the runway longitudinally. The pilot steered the aircraft to the left, where it eventually came to a stop a few meters from the aerodrome's perimeter fence. There were no injuries and no fatalities reported during the incident.
The investigation
The investigation focused on the mechanical failure of the engine during the takeoff phase. The aircraft had been stored in a hangar since 2001 and had recently undergone maintenance at a certified facility to return it to flight status.
Investigators examined the fuel system and discovered a perforation in a rigid fuel supply line that runs from the left wing to the fuel selector. This specific section of the line is located behind the instrument panel, making it difficult to access during standard inspections. The investigation established that during engine power application, air was being drawn into the system through this hole, which disrupted the fuel supply and caused the power loss.
Findings
- The primary cause of the engine power loss was the inadequate installation and securing of a fuel supply line.
- The improper positioning of the tubing caused it to come into abnormal contact with the flight controls.
- The combined effects of flight control movements and engine vibrations led to the abnormal wear and eventual perforation of the rigid fuel line.