What happened
A Cameron Z-350 balloon, registration G-CCSA, departed from a field near Monmouth for a planned one-hour passenger flight. While the initial weather conditions appeared clear, the flight encountered rapidly deteriorating conditions approximately 40 minutes into the journey. After observing lightning to the south and east and hearing thunder, the pilot attempted to land at a pre-selected site near Betts Newydd. However, this approach was aborted due to gusty winds and the presence of power cables across the flight path.
As the weather continued to worsen, the pilot was forced to seek an alternative landing site. Faced with increasing wind speeds and a lack of suitable terrain, an emergency landing was executed on uneven ground in the northwest of Pontypool. During the descent, the basket struck tree branches, causing a passenger to sustain a head laceration. The basket subsequently struck the ground hard, rolled onto its side, and was dragged across the surface. The accident resulted in two serious injuries (the pilot and one passenger) and 13 minor injuries.
The investigation
The AAIB investigation examined the meteorological conditions, the pilot's decision-making, and the aircraft's operational limitations. Investigators reviewed the Terminal Area Forecasts and radar imagery, which showed developing convective activity and the presence of cumulonimbus clouds in the vicinity of the accident. The investigation also reviewed the operator's manual, which prohibited flying in the presence of extensive thermal activity or thunderstorm activity.
Findings
- The pilot attempted to land in conditions that fell outside the operator's established operating limitations.
- The combination of high surface winds and local obstructions prevented the use of the intended landing area.
- The pilot made an emergency landing on uneven ground due to the lack of suitable alternative landing sites.
- The weather forecast indicated a 30% probability of thunderstorms, but the rapid development of convective cells was not visible to the pilot until the balloon was in close proximity.
- The provision of protective helmets was deemed necessary for flights over such terrain, though they were not provided for this flight.