What happened
On the evening of September 8, 2019, a Kubicek BB30Z hot air balloon was participating in the 'Vredefeesten' event in Sint-Niklaas, Belgium. After taking off from the city's market square, the pilot began a controlled descent toward a planned landing zone near Temse. While the approach initially appeared stable, the aircraft's descent rate suddenly accelerated from 1 m/s to 2.5 m/s when the balloon was only 40 meters above the ground.
Unable to perform a go-around due to the proximity of a river and existing ground speed, the pilot proceeded with the landing. The basket struck the ground forcefully and began to slide. During this movement, the basket crossed an irrigation ditch that was larger and more obscured by vegetation than the pilot had anticipated. The impact with the ditch's bank caused the pilot to lose balance, resulting in 1 serious and 2 minor injuries among the occupants. The pilot suffered a skull fracture and a broken nasal bone, briefly losing consciousness.
The investigation
The AAIU(Be) investigation examined the meteorological conditions, the aircraft's technical state, and the operational environment. Investigators found that while the pilot had received a briefing indicating potential instability, a new active weather cell had developed in the vicinity of Sint-Niklaas around 18:00 UTC, shortly before the landing. This sudden change in weather likely contributed to the unexpected descent rate.
Technical analysis of the aircraft focused on the basket's construction and the fuel cylinders. The investigation noted that the gas cylinders used during the flight featured unpadded top rings. While not a requirement for older aircraft, the investigators highlighted that such projecting objects could pose a risk to occupants during hard landings.
Findings
- The primary cause of the injury was the impact with the bank of an irrigation ditch during a hard landing.
- Unexpected meteorological instability, characterized by a new active weather cell, likely influenced the sudden increase in descent rate.
- The pilot's options were restricted by the presence of a nearby river and the balloon's horizontal speed, preventing a successful go-around.
- The presence of unpadded top rings on the fuel cylinders was identified as a potential safety risk for occupants during impact.