What happened
On June 22, 2002, an Aérospatiale SE 313 B Alouette 2, registration F-GHVQ, was conducting a private local flight near Toucy, France. The pilot, accompanied by three passengers, had departed from Auxerre airfield to perform aerial photography of a private estate.
After approximately fifteen minutes of flight, the helicopter was hovering roughly five meters above a pond, positioned near a shoreline lined with tall trees. As the pilot attempted to increase altitude by applying collective pitch, a loud metallic clacking sound was heard, and the power limit warning light illuminated. The engine experienced a surge, causing the aircraft to lose altitude rapidly. The pilot was unable to prevent the helicopter from striking the water. The aircraft capsized to the right and sank in the approximately 1.5-meter-deep pond. All four occupants successfully evacuated the aircraft without injury.
The investigation
The investigation focused on the engine's performance and the aircraft's weight and balance at the time of the accident. Investigators examined the engine and the governor, but subsequent bench testing revealed no mechanical malfunctions or defects.
Technical analysis determined that the aircraft's mass at the time of the accident was approximately 1,590 kg. Under the prevailing meteorological conditions—characterized by a temperature of 28°C (standard +13°C) and calm winds—the maximum allowable takeoff mass for Hover Out of Ground Effect (HOGE) was 1,560 kg. A simplified calculation method available to pilots would have estimated the maximum takeoff mass at 1,535 kg.
Investigators also noted that the aircraft was not equipped with life jackets for the occupants, nor did it possess a flotation system, which is a requirement for flights over water when a landing site is not immediately reachable in the event of an engine failure.