What happened
On the evening of July 23, 2013, a Kubiçek BB85Z hot air balloon, registration PH-WBI, departed from Amersfoort for a scheduled passenger flight. After initially ascending to approximately 2,000 feet, the aircraft encountered nearly windless conditions, leading the pilot to decide to terminate the flight and seek a landing site.
As the descent began, the wind conditions changed significantly. An attempt to land near an industrial area was aborted due to sudden wind increases of up to 20 knots. A subsequent attempt to land in a field between Baarn and Eemnes also failed when the basket was dragged through a reed bed. Driven by the lack of suitable land-based landing sites and approaching darkness, the pilot attempted to use the Gooimeer lake to slow the aircraft's momentum.
The pilot decided to drag the basket through the water to decelerate before reaching the shore near Almere Haven. During this maneuver, the basket was pulled partially submerged by the wind. As the aircraft reached the shoreline, a gust caused the balloon to rotate, causing the basket to roll over a stone embankment. This violent movement resulted in three injuries, including one serious injury involving a broken rib.
The investigation
The Dutch Safety Board (OVV) examined the meteorological data, the flight path, and the pilot's decision-making process. The investigation focused on why the weather conditions deviated from the forecasts provided by the KNMI (Royal Netherlands Meteorological Institute) and why the pilot chose a water landing despite the inherent risks.
Findings
- The primary cause of the accident was the pilot's decision to execute a water landing due to the lack of safe land-based alternatives caused by deteriorating weather.
- The weather conditions during the flight did not align with the forecasts provided by the KNMI, which had indicated that approaching storm cells were moving away from the area.
- The pilot's decision to land on the water was influenced by the necessity of avoiding obstacles, the approaching sunset, and the limited remaining gas supply.
- The landing on water exposed passengers to heightened risks, as the basket was not equipped with life jackets, as water crossings of that distance were not part of the original flight plan.
- The physical impact and rolling of the basket against the basalt stone embankment were the direct causes of the passenger injuries.