What happened
On Sunday, November 17, 2002, a Fly Synthesis Storch CL ultralight, identified as 37-LS, departed from the Tours-Sorigny airfield for a flight to Champrond-en-Gâtine. The pilot intended to rendezvous in mid-air with a second ultralight aircraft over a private landing strip in Chargé.
After approximately thirty minutes of flight, the two aircraft encountered deteriorating weather conditions near Vendôme characterized by heavy mist. The pilots, maintaining radio contact, decided to turn back and agreed to meet at the Amboise airfield. During this maneuver, the pilot of the second aircraft observed the 37-LS flying at an altitude between 50 and 100 meters. Witnesses on the ground reported hearing engine RPM fluctuations before seeing the aircraft climb sharply, then pitch into a steep dive, striking the ground behind a line of trees.
The investigation
The investigation focused on the engine performance and the environmental conditions at the time of the accident. Examination of the wreckage revealed that the Rotax 582 UL engine was not delivering power at the moment of impact. Technical analysis of the engine confirmed that a shutdown had occurred due to carburetor icing. It was noted that this specific aircraft was not equipped with a carburetor heat system.
Investigators also examined the aircraft's emergency equipment. Although the ultralight was equipped with a ballistic parachute, the low altitude of the aircraft at the time of the engine failure likely prevented the pilot from deploying the system. The pyrotechnic deployment mechanism was noted to have activated during the emergency response efforts.
Findings
- The primary cause of the engine failure was carburetor icing.
- The pilot failed to perceive the icing conditions present in the environment.
- A late decision to perform a turnaround contributed to the aircraft remaining in the icing-prone area.
- Meteorological data confirmed a low-pressure system was moving through the region, bringing low-level fog and mist that were evolving eastward during the late morning.