What happened
On August 16, 2020, a Balóny Kubíček BB51Z hot air balloon was conducting a commercial flight near St. Goar/Biebernheim, Germany. During the flight, the balloon encountered significant meteorological disturbances, including downbursts and wind shifts associated with an approaching thunderstorm and convergence line.
As the balloon approached its landing site, it experienced a rapid increase in wind speed and a significant descent rate. The first impact with the ground was extremely violent, occurring at approximately 47 km/．h. The force of this impact caused four passengers to be ejected from the basket. During a subsequent second impact, the pilot fell from the basket, clinging to the trailing rope. The balloon continued to drift, eventually crossing a steep slope in the Rhine Valley, where it finally came to rest among trees and bushes.
The investigation
The BFU investigation reconstructed the flight path using GPS data, which showed the balloon's speed increasing significantly as it descended through different wind layers. Investigators examined the aircraft's condition, finding no evidence of technical failure. The envelope showed various tears and some fire damage, but the structural components, including the burners and basket, were intact.
Meteorological analysis by the DWD confirmed that the area was subject to heavy wind activity from downbursts and a convergence line. The investigation also reviewed the pilot's decision-making process, including communications via chat portals and weather apps, and examined the manufacturer's recommended procedures for high-wind landings.