What happened
On May 13, 1962, a hot air balloon, registration HB-BIC, departed from Schlieren with a pilot and four passengers. Despite an unfavorable weather forecast, the pilot proceeded with the flight. During the journey, the balloon encountered cloud cover and eventually descended below the cloud base near Mosen. To avoid landing in a forested ravine, the pilot released ballast, which caused the balloon to rise back into the clouds for approximately 20 minutes.
As the weather conditions deteriorated, the pilot decided to descend through the clouds to land. At approximately 11:20, the balloon approached a 220 kV high-voltage power line near Ufhusen. While the pilot attempted to land, a wind gust pushed the partially deflated envelope toward the lines. The contact caused a short circuit, igniting the lifting gas. The resulting fire destroyed the balloon's envelope and netting, though the basket and equipment remained intact. All five occupants escaped the incident uninjured.
The investigation
The investigation examined the flight path, the meteorological conditions, and the pilot's decision-making process. Investigators reviewed the weather reports, which indicated that a low-pressure system was bringing heavy moisture and increasing cloud density, contrary to earlier optimistic forecasts. The commission also evaluated the technical state of the Balloonfabrik Augsburg balloon and the pilot's compliance with visibility regulations.
Findings
- The primary cause of the fire was a short circuit caused by the balloon envelope making contact with high-voltage power lines.
- The contact was triggered by a wind gust that moved the envelope toward the lines after the pilot had already initiated the landing sequence.
- The pilot's decision to continue the flight despite worsening weather and the necessity of flying through cloud layers contributed to the hazardous situation.
- The landing site was chosen due to the lack of better alternatives, but the terrain near the power lines was prone to wind channeling that was not easily predictable from altitude.