What happened
On November 11, 2000, at approximately 15:50Z, a Flamboyant Balloon AX 8-85, registration ZS-HOK, was undergoing a tethered ascent at a primary school in Brooklyn, Pretoria. The balloon was secured to the ground by three tether lines during its third lift. While the aircraft was at an altitude of roughly 15 to 20 feet, a sudden and powerful thermal or gust of wind originating from the west struck the balloon.
This unexpected weather event caused one of the three tether lines to snap. The loss of stability caused the balloon to drift eastward at approximately 20 feet above ground level. The pilot was unable to increase altitude quickly enough to avoid an obstacle, resulting in the basket striking the roof of a nearby office building. Following the impact, the balloon descended into Lange Street, landing in front of an ABSA Bank branch and causing damage to a section of the perimeter fencing.
The investigation
The investigation focused on the mechanical failure of the tethering system and the meteorological conditions present during the flight. Investigators examined the sequence of events leading from the initial line failure to the subsequent collision with the building. The inquiry confirmed that the aircraft was being operated for private purposes and that the pilot held a valid hot air balloon license.
Findings
- The primary factor in the accident was unsuitable weather conditions, specifically a sudden wind gust or thermal following recent thunderstorms.
- The sudden western gust caused the immediate failure of one tether line.
- The resulting imbalance and eastward drift led to the failure of the remaining two ropes.
- The pilot could not regain sufficient altitude to clear the roof of the office building.
- There were 3 minor injuries reported among the four occupants, including one passenger who sustained cuts to the hand and arm, but there were no fatalities.