What happened
On June 28, 2004, at approximately 21:15, a Cameron Balloons A 160 hot air balloon, registration F-GIET, was performing a recreational flight near Oisly, France. The pilot, accompanied by six passengers, began a descent toward a field bordered by vineyards. While maintaining an altitude of roughly 15 meters above the tree line, the pilot identified a low-voltage power line running parallel to the flight path, located about 30 meters to the left of the balloon.
During the descent, the pilot spotted a second, perpendicular low-voltage line approximately 50 meters ahead. To avoid this second obstacle, the pilot initiated a rapid deflation procedure to land before reaching the wires. The basket landed on a paved road and slid approximately ten meters before coming to a halt near the first set of power lines. As the envelope deflated, wind caused the fabric to drift and eventually collapse onto the low-voltage wires, which were positioned at a height of about five meters.
The investigation
The investigation focused on the sequence of events leading to the contact between the balloon envelope and the electrical infrastructure. Investigators noted that the ground crew, responsible for managing the envelope during deflation, arrived at the landing site approximately four minutes after the incident had occurred. The investigation also examined the visibility conditions, noting that at the time of the incident, the low contrast between the power lines and the surrounding vegetation made the obstacles difficult to detect.
Findings
- The primary cause of the incident was the envelope striking the power lines during the deflation process.
- The pilot experienced a delayed perception of the first obstacle due to a focus on the second, perpendicular power line detected during the descent.
- Environmental factors, specifically the low light levels and the lack of visual contrast between the wires and the vegetation, contributed to the difficulty in identifying the hazards.
- There were no injuries reported among the seven occupants.