What happened
On September 1, 2003, an Urban Air Lambada (identified as 31-BH) was conducting a flight training session at the Toulouse Bourg-Saint-Bernard aerodrome. The flight, involving an instructor and a student pilot, was intended as a handling flight. After a twenty-minute local flight, the pilot transitioned into a glider-mode approach for runway 30, performing the final approach with the engine shut down.
During the approach, the instructor noted a drift caused by winds from approximately 250°, despite the anemometer indicating a northerly wind. To compensate for a suspected wind gradient, the instructor instructed the pilot to increase the approach speed by 10 km/h to 95 km/h. Witnesses on the ground observed the aircraft on a normal descent path but noted that the flare maneuver was never initiated. The aircraft struck the ground while maintaining a constant pitch, sliding on its nose for approximately thirty meters. The nose gear collapsed, and the aircraft subsequently pitched forward and came to rest on its back.
Two persons were aboard the aircraft, and both the pilot and the passenger (the instructor) sustained injuries.
The investigation
The investigation focused on the aircraft's control surfaces and weight and balance configuration. Examination of the control linkages showed no anomalies prior to the impact. The investigation established that the aircraft was configured with a forward center of gravity (CG) of 20.15%, which sat at the extreme forward limit of the allowable 20% to 35% range. Both the pilot and the instructor reported that attempts to pull back on the control column to initiate a flare were ineffective.
Findings
- The primary cause of the loss of control during the flare was the forward center of gravity position.
- The aircraft's flight manual lacked specific instructions regarding center of gravity limitations, and the manufacturer had not demonstrated specific CG limits.
- A contributing factor was the potential underestimation of local aerodynamic effects near the ground, specifically wind variations that may have induced a stall.
Safety action
- Following the accident, the manufacturer released a new moment calculation sheet.
- The flight club implemented a prohibition on landing with the engine shut down.