What happened
On April 4, 1999, a SOCATA TB 20, registration F-GFZJ, was performing a local flight near Toussus-le-Noble. During the fourth circuit, following a landing, the pilot attempted to retract the flaps from 40° to 10° in accordance with the flight manual. During the subsequent initial climb, the pilot noticed abnormal aircraft behavior and realized the flaps had remained stuck at 40°.
In an attempt to manage the situation, the pilot decided to retract the landing gear. This action triggered the "gear not down" warning, which was consistent with the aircraft's configuration logic. The pilot did not notify the tower controller of the ongoing difficulties and proceeded to complete a full circuit of the airfield while attempting to resolve the flap issue. The landing gear warning remained active throughout the maneuver. Ultimately, the pilot performed a landing with the landing gear in the retracted position, resulting in damage to the flaps, fuselage, and propeller blades.
The investigation
The investigation focused on the mechanical state of the aircraft and the pilot's actions during the emergency. Investigators found that the flap circuit breaker had tripped. The investigation also examined the pilot's decision-making process and adherence to standard operating procedures during the period of mechanical malfunction.