What happened
On October 6, 1998, a commercial hot air balloon flight involving five passengers experienced a violent landing sequence near Zeven, Germany. During the flight, the pilot attempted several landing maneuvers, but none were successful for approximately 30 minutes. As the balloon approached the chosen landing site, it encountered sudden, increasing descent rates caused by thermal turbulence.
The basket made a hard impact with the ground, which the pilot was unable to cushion in time. The impact caused the basket to rebound and enter a pendulum motion, leading to a second hard contact with the ground. During these high-acceleration impacts, one passenger was ejected from the basket and sustained serious injuries, while a second passenger suffered back contusions. The aircraft, a Cameron N-1ast, sustained no damage, and no third-party property was affected.
The investigation
The BFU investigation established that the pilot had obtained weather briefings from the Hamburg meteorological service prior to departure. The forecast indicated surface winds of 8 to 10 knots from the east, with an increasing trend in wind speed at higher altitudes and the onset of thermal activity after 10:00 local time. The pilot attempted to complete the landing before the onset of these thermals, but the difficulty of finding a suitable landing area and the presence of shifting surface winds led to delays.
The investigation found that the balloon was not equipped with a rapid deflation system, which lengthened the landing phase and made a controlled approach difficult under the deteriorating weather conditions. The pilot was experienced, properly licensed, and familiar with the local terrain. The aircraft was found to be in airworthy condition with sufficient fuel remaining.
Findings
- The primary cause of the accident was the pilot's inability to execute a safe landing before the onset of thermal turbulence under challenging wind conditions.
- The sudden increase in descent rate due to thermals at low altitude left insufficient reaction time to prevent the initial hard impact.
- The high acceleration forces generated by the multiple impacts and the pendulum motion overwhelmed the passengers, despite instructions to hold onto the basket.
- The lack of a rapid deflation system contributed to the prolonged landing phase during unstable weather.