What happened
On 25 June 2017, an Ultramagic T180 hot air balloon, registered F-GTBL, was conducting a commercial flight near Sandillon, France. The pilot, carrying eight passengers, departed from Jouy-le-Potier for a scheduled one-hour flight. During the flight, the pilot noted atmospheric instability and prepared the passengers for a potentially firm touchdown.
As the balloon approached a chosen landing field, it encountered a sudden downdraft while passing over a wooded area. The balloon struck the treetops, prompting the pilot to use the burners to regain altitude. To avoid an approaching power line at the edge of the field, the pilot activated the Rapid Deflation System (RDS) to force a quick descent. This maneuver resulted in a hard landing, causing the basket to tip onto its side and slide along the ground. The impact caused one serious injury (a fractured ankle) and one injury (a herniated disc) among the passengers, while the pilot and remaining six passengers were unharmed.
The investigation
The BEA examined the flight path, meteorological conditions, and the physical configuration of the basket. Investigators analyzed the pilot's maneuvers, specifically the use of the RDS to avoid power lines, and the passenger positioning during the impact. The investigation also reviewed the basket's capacity and the ergonomics of the passenger compartments, noting that the specific configuration of the F-GTBL basket made it difficult for all passengers to adopt the optimal safety position.
Findings
- The primary cause of the accident was the rapid descent initiated by the use of the RDS to avoid power lines, which led to the heavy impact.
- Wind conditions at the landing site created turbulence that destabilized the approach slope.
- The pilot's choice of landing site was constrained by the presence of trees and power lines, forcing an aggressive descent maneuver.
- The passenger who suffered a fractured ankle was in a tandem position (one passenger behind the other) with legs together, which likely caused an excess load on the ankle during the impact.
- The basket's geometry prevented all passengers from easily adopting the recommended side-by-side safety position.