What happened
On May 31, 1999, an Eurocopter AS 350 B1, registration F-GJCM, was performing sling-load operations in the French Guiana region near Camopi. The mission, operated by an aerial work company, originally planned to transport cargo with a specific fuel reserve. However, after arriving at Camopi, the pilot accepted an additional task to transport two diesel drums to refuel a mechanical excavator in the forest.
During the return leg, the low-fuel warning light illuminated approximately four minutes before landing at Camopi. The pilot, believing there was enough fuel to reach Crique Eaux Claries, departed with another sling load. During the subsequent flight, the pilot became uncertain of the remaining fuel and released the load to attempt a return. As the aircraft accelerated, the pilot significantly changed the aircraft's pitch, which caused the engine to flame out. The pilot attempted an autorotation over the dense forest canopy, ultimately pitching the aircraft nose-up at the last moment to land on the tail boom to protect the cabin. The helicopter struck the trees and overturned on its right side.
The investigation
Investigators examined the wreckage in the dense jungle and found the airframe destroyed, though the tail boom remained relatively straight and the engine appeared intact. The fuel tank was not punctured and contained only a few liters of fuel.
Technical analysis focused on the fuel consumption logs and the pilot's flight maneuvers. The investigation reconstructed the flight stages, revealing that while the initial fuel planning was technically sound, it left a very narrow margin of only about eight minutes of extra flight time. The additional mission and slight delays in earlier flight segments consumed this entire margin. Furthermore, investigators reviewed the flight manual, which specifically advises avoiding significant changes in pitch once the low-fuel warning light is illuminated.
Findings
- The primary cause of the accident was the continuation of the mission with insufficient fuel due to tight fuel management.
- The decision to perform an unplanned additional mission without recalculating the fuel requirements acted as an aggravating factor.
- The engine flameout was triggered by a significant change in aircraft pitch, which violated the precautions outlined in the flight manual regarding low-fuel conditions.
- The pilot's survival was attributed to a successful autorotation maneuver, influenced by his memory of a previous accident involving a similar engine failure.