What happened
On September 26, 2008, a Dyn'Aero MCR 01 ultralight, registration 34-ABY, departed from runway 32 at the Montpellier Candillargues airfield for a local flight. The pilot was accompanied by one passenger. Immediately following rotation, the pilot encountered significant difficulty maintaining a climb attitude. As the aircraft became uncontrollable, the pilot attempted to deploy the emergency parachute; however, the parachute did not fully deploy before the aircraft struck the ground at an approximately 45-degree nose-down attitude. The impact resulted in two injuries and heavy damage to the aircraft.
The investigation
The investigation focused on the configuration of the aircraft's flaps at the time of the accident. Although the pilot had set the flap lever to the "takeoff" position, examination of the wreckage revealed that the actual flaps were in the "landing" position. The aircraft was equipped with an optional computer designed to manage the flap drive motors by comparing the lever position to the actual flap position. Investigators discovered an electrical short circuit caused by a poorly connected pin within this system.
It was noted that the pilot had placed aeronautical documentation in the space between the seat and the fuselage wall, near the computer's wiring. During taxiing, this documentation likely moved and made contact with the wiring, contributing to the electrical anomaly. Additionally, investigators reviewed existing safety precautions, noting that the pilot was aware of a 2006 DGAC recommendation prohibiting the use of full flaps (45°) on this aircraft type and had even marked the lever with red tape to prevent such an error.
Findings
- An electrical short circuit on a pin caused the flaps to extend to the landing position, likely during the takeoff roll.
- The movement of cockpit documentation may have caused physical tension on the electrical connection, triggering the fault.
- A potential design vulnerability in the Dyn'Aero MCR 01 makes aircraft control hazardous when flaps are in the landing configuration during takeoff.
- The pilot's experience and the timely attempt to deploy the emergency parachute helped mitigate the severity of the injuries.