Balloon strikes tree during low visibility flight near Ashton Keynes

Casualties unknown • 1 mile south of Ashton Keynes, Wiltshire, GB

A Cameron Z-315 balloon carrying 17 people became lodged in an oak tree after flying into fog, an accident investigators say could have been avoided by delaying launch.

What happened

On 10 September 2006, a Cameron Z-315 balloon, registration G-KNIX, launched from a site near Lydiard Hall, Swindon, for a scheduled public transport flight. Although the pilot had received a forecast suggesting visibility would improve, the actual visibility at the time of launch was only a few hundred metres, significantly below the 5 km requirement for Visual Flight Rules.

As the balloon ascended, it entered a thick layer of fog. While flying above the fog, the pilot used a map to identify potential landing sites. During a descent into the fog, the pilot encountered power lines, which required an immediate climb to avoid a collision. A second descent was attempted, but during this maneuver, the balloon struck a large oak tree. The impact caused a limb to puncture the balloon envelope, and the aircraft became lodged in the tree. After the pilot used burners to break the balloon free, the craft climbed to approximately 1,500 ft before the pilot was able to perform a safe landing near the Cotswold Water Park.

The investigation

The AAIB investigation examined the pilot's flight planning, the weather conditions, and the operator's compliance with flight time limitations. Investigators noted that the pilot had not received specific training for operating above fog, nor were there established procedures for such scenarios. The investigation also reviewed the pilot's duty records, finding that the required rest period prior to the flight had not been taken. Furthermore, the aircraft was found to be carrying 17 people, exceeding the operator's maximum limit of 16.

Findings

  • The pilot launched when visibility was significantly below the legal minimum.
  • The pilot failed to delay the launch until visibility had improved to 5 km.
  • The pilot's decision to fly was likely influenced by the belief that the fog would clear or by potential fatigue from inadequate rest.
  • The aircraft's map did not include small-scale obstructions like the trees and power lines encountered.
  • The balloon exceeded its maximum permitted occupancy during the flight.

Probable cause

The accident was caused by the pilot's decision to launch the balloon while visibility was below the required minimum for VFR flight, combined with a lack of specific training or procedures for navigating above fog layers.

Frequently asked questions

What happened in the 2006-09-10 Cameron Z-315 Balloon, G-KNIX accident near 1 mile south of Ashton Keynes, Wiltshire, GB?

A Cameron Z-315 balloon carrying 17 people became lodged in an oak tree after flying into fog, an accident investigators say could have been avoided by delaying launch.

What aircraft was involved and where did it happen?

The accident on 2006-09-10 involved a Cameron Z-315 Balloon, G-KNIX, registration G-KNIX, at 1 mile south of Ashton Keynes, Wiltshire, GB.

What was the probable cause of the accident?

The accident was caused by the pilot's decision to launch the balloon while visibility was below the required minimum for VFR flight, combined with a lack of specific training or procedures for navigating above fog layers.

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