What happened
On August 26, 2011, three Schroeder fire balloons / fire balloons G 42/24 hot air balloons were conducting a flight near Adelebsen, Germany. The flight, which included a total of 15 passengers and three pilots, began shortly after 18:00. While the flight initially proceeded in a northerly direction, the pilots noticed significant changes in wind conditions around 18:30. Specifically, the rotation of wind turbines in the area suggested a sudden increase in wind speed and a shift in wind direction.
In response to the deteriorating weather, the pilots attempted to land. However, the aircraft became uncontrollable during the low-altitude landing phase. The first balloon struck trees and drifted into an orchard, resulting in 5 light injuries. The second balloon was struck by a wind gust, causing it to hit a hedge and drag across an open field for approximately 560 meters; this incident resulted in 6 serious injuries, including the pilot. The third balloon landed on a stubble field and was stopped by a thicket, causing 5 injuries (2 serious, 3 light).
In total, the accidents caused 8 serious injuries and 9 light injuries, along with significant damage to the three aircraft and local vegetation.
The investigation
The BFU investigation focused on the meteorological conditions, the pilots' preparations, and the organizational structure of the operating company. Investigators examined the flight paths, the condition of the balloons, and the weather briefings obtained by the pilots. The investigation also scrutinized the company's management, noting that the roles of managing director, flight operations manager, and technical manager were held by a single individual, which lacked internal safety oversight. Furthermore, the investigation found that the pilot of the first balloon was not properly authorized to conduct commercial operations under the company's permit.
Findings
- The primary cause of the accident was that the balloons were caught by the strong winds of a dry convergence line (a squall line), which caused the aircraft to lose control during landing.
- The pilots failed to obtain a timely weather briefing immediately before takeoff, which would have likely revealed the approaching wind gust line.
- There was an inadequate interpretation of existing weather data.
- The aviation authority had not conducted a technical or operational audit of the operator in eleven years, representing a failure in continuous oversight.