What happened
On Wednesday, April 15, 1998, at 16:50, a SOCATA TB 20, registered F-GKUR, was performing a training flight from Toussus-le-Noble toward Dreux. The aircraft was occupied by an instructor and a student pilot. During the takeoff roll on runway 25, the aircraft began to sink as it reached rotation speed. Although the instructor took control of the aircraft, the plane could not be prevented from veering off the runway to the right.
The excursion resulted in damage to the engine, the propeller, and the footrests. The aircraft's right main landing gear and nose gear were found to be collapsed following the event. Weather conditions at the time included a temperature of 6 °C and winds from 240° at 15 to 20 knots.
The investigation
The investigation focused on the configuration of the aircraft's landing gear prior to departure. Testing performed on hydraulic jacks demonstrated that the landing gear mechanism was functioning normally.
Investigators determined that the landing gear lever had been left in the retracted position. It was established that the student pilot had failed to check the position of the gear lever during both the pre-flight inspection and the pre-start/taxi checklists. The instructor also failed to verify the lever position.
Notably, earlier that morning, classroom-style instruction had taken place inside the cockpit of the aircraft to familiarize students with the TB 20's layout. The flight manual explicitly requires that the landing gear lever be in the "down" position during both the pre-flight inspection and the engine start procedures.