What happened
On the evening of July 22, 2017, a Cameron C80 hot air balloon, registration G-CGPV, participated in a mass ascent event at the Chambley-Bussières airfield. The flight, carrying a pilot and one passenger, departed at approximately 20:25.
During the flight, the pilot attempted an initial landing approach but aborted due to wind shifts and the presence of other balloons. Subsequent attempts to find a suitable landing site in Rezonville and near Augny were unsuccessful. As the balloon moved toward Magny, it entered a thunderstorm cell. Witnesses observed the aircraft flying through heavy rain, which significantly weighted the envelope. The pilot reported that the balloon was caught in a downdraft, making flight control extremely difficult.
In an attempt to avoid further danger, the pilot initiated an emergency landing in a field bordered by trees. Shortly before impact, the pilot closed the gas valves and deflated the envelope. At 21:32, the balloon collided with trees at a ground speed of approximately 20 knots. The envelope tore upon impact, which cushioned the descent of the basket. The pilot and passenger were evacuated from the scene uninjured.
The investigation
The BEA examined the meteorological conditions, the flight trajectory, and the decision-making processes of both the flight director and the pilot. The investigation reviewed weather briefings provided at 18:00, which indicated a risk of rain after 21:00 and thunderstorms after 23:00. Furthermore, updated Météo-France forecasts from 19:00 warned of deteriorating conditions, including rain showers, reduced visibility, and wind gusts of up to 30 knots.
Findings
- The flight director may have underestimated the evolving weather due to organizational pressures and the presence of the public, authorizing the mass ascent despite forecasts of rain and storms.
- The pilot's decision to depart was influenced by organizational and collective pressure associated with the mass ascent event, as well as an over-reliance on the flight director's authorization.
- The pilot did not update the weather information received during the initial briefing prior to takeoff.
- The heavy rain caused the balloon envelope to absorb water, increasing its weight and contributing to the loss of control within the storm cell.