What happened
On July 20, 2014, during a competitive flight as part of the World Hot Air Balloon Championships in Rio Claro, Brazil, a collision occurred between two hot air balloons. The lower-flying balloon, a Cameron TR 70 with registration SP-BBP, operated by Aeroklub Włocławski, collided with a second balloon (a Kubicek BB22) flying at a higher altitude.
The impact of the higher balloon's basket against the upper portion of the SP-BBP envelope caused an extensive tear in the fabric. Due to the severity of the damage, the pilot was unable to continue the flight and performed an emergency landing in a residential yard. The crew sustained light injuries during the incident.
The investigation
The Polish State Commission on Aircraft Accident Investigation (PKBWL) initiated the investigation after being notified by the Brazilian authority, CENIPA. Although the PKBWL requested documentation from CENIPA, no copies of the requested documents were received by the time the investigation concluded.
Investigators analyzed available information regarding the flight conditions, noting that the balloons were flying at relatively low altitudes with small vertical velocities. Strength testing of the SP-BBP envelope revealed the material was three times stronger than the required minimum. However, an examination of the basket of the higher-flying balloon revealed sharp-edged elements protruding from the exterior. It was determined that these sharp edges likely caused the fabric tear during the contact.
Findings
- The primary cause of the accident was the failure to maintain separation between the two balloons.
- The intense focus on competition results during the world championship likely contributed to the lack of separation.
- The presence of sharp, protruding elements on the exterior of the higher balloon's basket acted as a contributing factor to the envelope failure.
- The low altitude at which the collision occurred prevented more serious injuries to the crew.