What happened
On August 20, 2006, a Socata TB 20 (registration F-GDGM) was performing a VFR flight from Cannes, France, to Valbrembo, Italy. During the final approach, the pilot configured the aircraft with the flaps extended and the engine at idle power but failed to extend the landing gear.
The aircraft made contact with an asphalt taxiway located east of the main grass runway, approximately 136 meters beyond the threshold. The aircraft traveled 198 meters before coming to a stop. The impact resulted in damage to the propeller and the lower fuselage, though the two occupants remained uninjured.
The investigation
The ANSV investigation focused on why the landing gear was not deployed and why the pilot was not alerted. Post-accident functional tests revealed that while the landing gear retraction/extension mechanism was operating correctly, the audible warning alarm was non-functional. Under the configuration used during approach (flaps extended and low power), the alarm should have activated to notify the pilot of the gear's position, but it remained inactive.
The investigation also identified discrepancies in the aircraft's maintenance logs. It was noted that flight hours were added retroactively, leading to inaccurate total time calculations. Furthermore, during a 50-hour inspection performed two days prior to the accident, unprogrammed tests on the landing gear were conducted, suggesting potential pre-existing issues that were not documented.
Findings
- The primary cause of the accident was the pilot's failure to extend the landing gear during the landing phase.
- A contributing factor was the malfunction of the cockpit audio alarm, which failed to alert the pilot to the improper configuration.
- The aircraft landed on an asphalt taxiway that is officially reserved for glider and glider-towing movements, though it was noted that this surface is habitually used for powered aircraft landings.
- Inaccurate maintenance record-keeping was identified, specifically regarding the retrospective logging of flight hours.