What happened
On July 9, 2004, at 11:35 AM, a Schleicher ASW 20 L glider, registration 4627 JMQ, was performing a local winch launch from the La Motte-du-Caire airfield. The flight began normally, with the winch operator applying tension and the aircraft accelerating as expected. However, witnesses noted that the glider failed to adopt its typical climbing attitude after liftoff.
In an attempt to assist the climb, the winch operator increased the pulling power. Despite this increased tension, the glider continued to fly in a flat attitude. The operator subsequently decided to stop the winch, causing the cable to slacken and detach. Once the cable was released, the glider entered a nose-down pitch and maintained this attitude until it struck the ground. The accident resulted in one fatality and the total destruction of the aircraft.
The investigation
The investigation focused on the elevator control mechanism, which features a specific design to allow the control chain to be disconnected for ground transport. This system utilizes a spherical joint attached to the elevator, which is secured within a socket by a locking key.
Upon examining the wreckage, investigators found that the spherical joint was not in place and the locking key was not in the locked position. No signs of mechanical failure, breakage, or abnormal wear were found on the components, and subsequent tests confirmed that the mechanism was fully functional. The investigation also established that while the pilot had received assistance with wing assembly earlier that morning, the pilot had personally performed the connection of the control surfaces.
Findings
- The primary cause of the accident was the failure to properly connect the control chain to the elevator control linkage.
- The pilot had omitted the necessary steps to secure the elevator control system following the assembly of the aircraft.