What happened
On 30 September 2011, a Cameron Z-400 hot air balloon, registration G-VBFV, was being prepared for a commercial passenger flight at Shuttleworth Park, Old Warden, Bedfordshire. The aircraft was fully inflated and positioned above the basket, with a launch restraint system in place to secure the burner frame to a nearby vehicle.
Following a safety briefing regarding boarding procedures and landing positions, the pilot instructed the passengers to enter the basket. As the passengers were boarding, the basket moved, causing one passenger to lose his footing and fall to the ground. The passenger sustained a serious injury, specifically a fracture to his upper arm. The ground support crew assisted the injured individual away from the balloon, and the flight proceeded as planned.
The investigation
The investigation examined the circumstances surrounding the movement of the basket during the boarding phase. The pilot initially reported that the passenger had simply missed his footing. However, the investigation also considered statements from two witnesses who observed that a gust of wind had caused the basket to shift. Data from the Met Office indicated that the mean surface wind strength at the time of the incident was within the manufacturer's specified limits for takeoff.