What happened
On August 19, 2016, during a ballooning competition at the Kruszyn airfield (EPWK), a Lindstrand LBL 77X balloon, registration SP-BPM, operated by Aeroklub Włocławski, was being prepared for flight. The pilot, with 59 flight hours, had begun filling the envelope with cold air. According to the pilot's statement, once the envelope was approximately 70% to 80% full, both burners were activated to begin intensive heating.
During this process, the upper portion of the envelope rose rapidly while the lower section and the basket remained horizontal. Because the envelope was not yet fully inflated, the upward movement of the fabric prevented the pilot from maintaining adequate separation between the burners and the material. The burners were shut off too late, resulting in thermal damage to four sections of the material above the Nomex layer.
The investigation
The investigation established that the pilot initiated the heating process before the envelope had reached a sufficient volume of cold air. The pilot stated that this decision was driven by time pressure, as the competition's launch window was closing and the pilot sought to avoid penalty points. The investigation also noted that using two burners simultaneously during the inflation stage causes a highly dynamic rise in the top of the envelope, which is difficult for a crew member holding the crown line to control.
Findings
- The primary cause of the incident was the decision to begin heating the air within the envelope before it was sufficiently filled with cold air.
- The pilot's desire to avoid competition penalties led to a departure from standard preparation procedures.
- The use of dual burners during the early stages of inflation created an unstable and difficult-to-manage movement of the envelope fabric.
- The lack of internal pressure in the partially filled envelope made the fabric more susceptible to wind gusts and closer proximity to the burner flames.