What happened
On July 16, 2004, at approximately 15:00, an Altania 12 and RG prototype, registered F-WWMU, was conducting a test flight near Clermont-Ferrand. The flight was being operated for a private purpose, with the pilot accompanied by a passenger. Shortly after takeoff, the pilot temporarily handed control of the aircraft to the passenger.
During the flight, a known electrical issue was present: one of the three green landing gear down-lock indicators remained illuminated even though the gear was retracted. During the approach for runway 08, the pilot commanded the extension of the landing gear and the first notch of the flaps. Upon reaching short final, the pilot reassumed control. During the flare, the aircraft exhibited unusual behavior, appearing to resist the ground. Consequently, the propeller struck the runway, and the aircraft landed with the landing gear retracted, sliding on its fuselage before coming to a stop on the runway. The impact caused damage to the propeller, flaps, and the underside of the fuselage. There were no fatalities or injuries among the two occupants.
The investigation
The investigation focused on the landing gear extension mechanism and the electrical system. Investigators found the landing gear control in the "extended" position. However, the circuit breaker for the landing gear actuation motor, located on the right side of the instrument panel, was found tripped.
It was established that the aircraft's alternator provided insufficient power, which could cause the landing gear motor circuit breaker to trip after multiple gear cycles. The pilot noted that while he believed all three green lights were illuminated after commanding the gear down, he may have been misled by the fact that one light had remained illuminated during previous flight segments.