What happened
On 29 October 2006, a Cameron Z-315 hot air balloon, registration G-KNIX, was conducting a commercial passenger flight near Alton, Hampshire. The flight, carrying one pilot and 16 passengers, was intended to last approximately one hour. During the flight, the pilot identified a suitable stubble field for landing but needed to secure permission from the landowner via the support crew.
As the balloon drifted across the field at an altitude of approximately 20 to 30 feet, the pilot awaited a decision from the ground crew. During this period, a gust of wind increased the balloon's ground speed to 8 knots. Realising the balloon would not stop within the field, the pilot attempted to climb out by using the burners. However, while managing the parachute valve and burners, the balloon struck a 20-meter-high beech tree. The impact caused several branches to enter the basket, resulting in one minor injury to a passenger who sustained cuts to her head. The collision also caused significant damage to the balloon's envelope.
The investigation
The AAIB examined the sequence of events, the aircraft's condition, and the operational procedures of the company. The investigation looked into the pilot's actions during the landing approach and the technical state of the G-KNIX envelope following the impact. The investigation also reviewed the company's operations manual and the weight and balance of the flight.
Findings
- The collision with the tree was caused by the pilot failing to prioritise flight safety over the need to obtain landing permission, which left the balloon at a low altitude while awaiting a decision.
- An unexpected gust of wind contributed to the balloon's inability to stop within the intended landing area.
- The pilot's attempt to climb out was complicated by the physical difficulty of operating the burner controls and the parachute valve simultaneously.
- The aircraft was operating with 17 occupants, which exceeded the number of passengers specified in the company's insurance, though the total weight remained within the permitted lift capacity.
- The company's operations manual contained an error regarding the maximum number of occupants due to an oversight during compilation.
Damage assessment
Following the accident, the envelope was returned to the manufacturer for repair. The assessment revealed that seven panels of the Cameron Z-315 envelope had been damaged; three panels required complete replacement, three were partially replaced, and one was patched.