What happened
On the night of July 4, 1997, an Aérospatiale AS 350 B Ecureuil, registration F-GDFG, was engaged in a medical evacuation mission (EVASAN) from the village of Espezel to the Carcassonne University Hospital. The mission was initiated following a request from a physician to transport an unconscious patient. After landing at a sports field in Espezel to collect the patient and medical crew, the helicopter departed at 22:51.
During the return flight, the pilot encountered deteriorating weather conditions characterized by heavy rain, thunderstorms, and gusty winds. To maintain visual contact with the ground, the pilot utilized illuminated villages as navigational landmarks. While flying near the village of Puivert, the aircraft made a sharp turn to the right. Witnesses near the hamlet of Saint-André observed the helicopter flying at a very low altitude before seeing a bright flash and hearing an explosion. The aircraft had struck the treetops of a densely forested ridge at high speed, causing the helicopter to disintegrate and catch fire.
The investigation
The investigation focused on the flight path, the meteorological conditions, and the decision-making process regarding the mission. Investigators examined the wreckage, which was heavily damaged by the high-speed impact and subsequent fire. Analysis of the turbine confirmed that the engine was delivering significant power at the moment of impact.
Investigators also reviewed the pilot's experience and the operational context of the mission. The investigation noted that the medical team arrived at the aircraft quickly after the mission was triggered, without prior consultation of meteorological reports. The investigation also examined the regulatory requirements for night VFR (Visual Flight Rules) flight, which mandate specific visibility and ceiling minimums that were not met at the time of the accident.
Findings
- The primary cause of the accident was continued flight in mountainous terrain under weather conditions that did not meet VFR requirements.
- The pilot was flying at a low altitude to maintain visual reference with the ground due to rapidly degrading visibility caused by an approaching storm front.
- The decision to proceed with the mission was influenced by the urgent nature of the medical emergency, which created pressure to execute the evacuation despite the worsening weather.
- The pilot did not have sufficient time to review updated meteorological information before departure.
- The aircraft struck the terrain while attempting to maneuver around a thunderstorm cell.