What happened
During the pre-inflation stage of a sunrise sightseeing flight, a sudden shift in wind direction and strength caused the balloon envelope to strike two nearby light poles. This impact resulted in a tear in a panel above the equator of the envelope, measuring at least 4CO cm. This damage exceeded the manufacturer's allowable limits for adhesive tape repairs. While passengers waited, the pilot applied adhesive tape to the tear. Following hot inflation and an inspection that showed no immediate issues, the pilot decided to proceed with the flight. During the flight, the tape repair began to degrade, though the pilot managed to complete a safe landing.
The investigation
Investigators examined the launch site and the repair process. They found that the chosen launch position did not provide enough clearance from surrounding obstacles to safely manage the envelope during inflation. Regarding the repair, the investigation determined that the pilot, acting as the maintainer, failed to follow the operator's manual or the manufacturer's specific instructions. While adhesive tape is permitted for small tears up to 10 cm, the 45 cm tear required a sewn panel repair, which would have necessitated canceling the flight. The pilot's reliance on previous experience with minor repairs likely led to the incorrect assessment that the tape was sufficient.
Findings
- The launch area lacked sufficient space to ensure the envelope remained clear of obstacles during preparation.
- A sudden wind change caused the envelope to contact light poles, creating a significant tear.
- The repair performed by the pilot did not comply with manufacturer requirements.
- Plan continuation bias likely influenced the decision to fly, driven by improving weather and the desire to meet passenger expectations.
- The pilot did not land immediately upon noticing the repair degrading in flight, despite manufacturer instructions to land as soon as possible following envelope damage.