What happened
On September 11, 1999, a L.Stuttgart/K-1000/3-Stu gas balloon departed from Freital as part of a ballooning event with four people on board. The flight, led by a highly experienced pilot with over 6,000 flight hours, proceeded through various altitudes to avoid thermal influences, eventually crossing the Saale river near Friedeburg.
As the flight approached Hettstedt, the pilot initiated landing procedures from an altitude of approximately 1,200 meters. Despite releasing four bags of sand ballast and disconnecting the drag rope to reduce descent speed, the balloon basket experienced a very hard first impact with the ground. Following this initial contact, the balloon lifted off the ground again by approximately 20 to 25 meters. During this secondary ascent, the vent line was fully opened, leading to a second, equally violent impact about 60 meters later. The basket tipped over upon landing. The incident resulted in two serious injuries among the passengers.
The investigation
The BFU investigation focused on the environmental conditions and the sequence of manual interventions during the landing. Investigators examined the wind conditions, noting that while the pilot had requested wind information from Leipzig and Halle, ground winds were approximately 13–15 knots with gusts exceeding 17 knots—higher than the pilot had anticipated.
The investigation also scrutinized the roles of the crew members. A second pilot on board had been assigned navigation and radio duties and was specifically instructed to operate the rip cord for rapid deflation. The investigation found that the pilot was unaware that this crew member lacked practical experience with the specific rip cord mechanism of this aircraft type. Furthermore, while a briefing on landing procedures was provided immediately before landing, the passengers were not briefed at the start of the flight and were unable to cope with the sudden acceleration forces during the impact.
Findings
- The primary cause of the accident was the inability to sufficiently reduce the descent rate prior to the first ground contact.
- Landing conditions were complicated by 13-knot winds, thermal activity, and leeward turbulence caused by the hilly terrain and a large depression at the landing site.
- The vent line was only partially opened during the first impact, which failed to sufficiently reduce the balloon's lift, allowing for the subsequent uncontrolled ascent and second hard impact.