What happened
On 25 March 2012, a Cameron N-77 hot air balloon, registration G-BEEI, was conducting a private flight near Bozeat, Northamptonshire. The flight, which included the pilot and two passengers, had been proceeding normally at approximately 500 ft agl under favorable weather conditions.
As the pilot prepared to land at a playing field, they were alerted by another balloon pilot to the presence of windshear in the area. Despite this warning, the pilot continued the approach toward a landing site located roughly 7.5 nm downwind from the takeoff point. During the descent, the balloon encountered a sudden, steep loss of altitude. In an attempt to avoid the 132 kV transmission lines running adjacent to the intended field, the pilot engaged both burners; however, the aircraft struck the wires above the level of the burner and basket.
The impact caused the balloon to slide along the lines before coming to a halt against a support pylon, with the basket suspended roughly 15 m above the ground. A small fire ignited in the basket but was quickly extinguished. The pilot and one passenger sustained minor injuries, specifically small singeing burns, while the third occupant was uninjured.
The investigation
The investigation established that the balloon entered a period of unexpected descent while approaching the power lines. The pilot reported encountering windshear during the landing phase that was more intense than any previously experienced. Other pilots flying in the same group confirmed that low-level windshear had been present both en route and within the landing area.
Emergency response was delayed due to the high-voltage nature of the site. Because the accident occurred on the boundary of two different electricity distribution network operators, strict safety protocols required engineers from three separate locations to attend the scene to ensure the lines were isolated and eutely earthed. Consequently, rescue operations could not begin until approximately 2130 hrs.
Findings
- The primary cause of the accident was the encounter with windshear during the landing approach.
- The pilot did not sufficiently account for the potential for unusual atmospheric conditions following the warning from another crew.
- The balloon's contact with the transmission lines resulted in holes in the envelope and minor burns to the basket.