What happened
Shortly after departing at approximately 0540, a hot air balloon operated by OKX encountered significant turbulence and strong winds. While the pilot initially believed the turbulence was caused by the penetration of an inversion layer due to rising temperatures, the flight conditions were actually consistent with existing weather forecasts.
As the aircraft drifted from its planned path, the pilot identified a clearing for an emergency landing. However, due to a ground speed of approximately 20 kt, the landing required a substantial stopping distance. During the landing, the basket tipped onto its side and was dragged across the terrain. A pocket of hot air remained trapped in the envelope, causing it to act like a sail and pull the basket toward a large bush. The basket struck the vegetation, which launched the basket back into the air before it settled on one corner. The subsequent impact with the ground caused four injuries to the passengers.
The investigation
The investigation examined the meteorological data and the landing mechanics. While the operator believed a sudden temperature increase had disrupted the atmosphere, a review of the GPWT and GAF forecasts showed that temperatures and increasing wind speeds at altitude were already predicted. The ATSB determined that the turbulence was likely caused by mechanical effects from the strong winds rather than an inversion layer.
Furthermore, investigators found that the landing area, while initially clear in the direction of travel, became hazardous when the wind direction shifted the basket's path. The investigation also noted that the pilot's decision to land in an unfamiliar clearing under such conditions contributed to the outcome.