What happened
On May 21, 2011, a Lindstrand 180A hot air balloon, registration F-GSUI, was conducting a one-hour discovery flight near Thouaré sur Loire, France. The aircraft was carrying the pilot and eight passengers. As the pilot approached the landing site, he identified a field for touchdown but noted a nearby fence that appeared to be barbed wire.
Upon touching the ground, the pilot activated the rapid deflation system by pulling the red release cord. Fearing damage to the envelope from the nearby fence, the pilot attempted to take off again to find a safer landing area. To achieve this, he released the red cord and used both burners to maximum capacity to increase internal temperature. However, the envelope failed to regain sufficient altitude to clear the overhead catenary wires of a nearby railway line located approximately 100 meters from the initial touchdown.
As the balloon attempted to pass the railway, the envelope made contact with the power lines. The resulting electrical arc created sparks that ignited a small fire on the ground. While the pilot was able to extinguish the fire quickly, the heat caused the polyester clothing of two passengers to burn, though no injuries were sustained.
The investigation
The investigation focused on the functionality of the rapid deflation system and the pilot's decision-making process. Investigators examined the mechanics of the envelope's top vent, known as the parachute, which is designed to seal the top of the envelope via internal air pressure. While a standard red and white cord allows for controlled deflation and subsequent resealing, the specialized red cord used in this incident is intended for rapid deflation by physically displacing the parachute downward.
It was established that after the pilot released the red cord, the parachute did not return to its original sealing position. This prevented the envelope from maintaining the necessary heat and pressure to climb effectively. The investigation also noted that the proximity of the railway lines left the pilot with very little margin to correct the malfunction or regain altitude.
Findings
- The primary cause of the accident was the pilot's decision to abort the initial landing after having already activated the rapid deflation system.
- The release of the red cord caused the parachute to remain improperly positioned, preventing the envelope from regaining sufficient altitude.
- The proximity of the railway catenary wires limited the pilot's ability to resolve the technical issue before contact occurred.
- The use of synthetic polyester clothing contributed to the minor fire incident involving passenger clothing.