What happened
On May 14, 2022, at approximately 09:50 local time, a CAMERON Z-250 hot air balloon, registration EC-NLO, operated by Globos y Dirigibles Boreal S.L., departed from near Friamonde, Lugo, for a local tourist flight. The aircraft was carrying one pilot and ten passengers.
Approximately 30 minutes into the flight, the crew observed storm clouds approaching from the south. As the aircraft's ground speed increased significantly, the pilot attempted to descend to find a suitable landing site. During this maneuver, the balloon encountered a sudden and violent change in wind speed and direction, known as wind shear. This phenomenon caused a loss of lift and an uncontrolled descent.
During the descent, the basket struck and toppled a concrete utility pole in Soengas de Abaixo, becoming entangled in the electrical cables. The momentum caused a second pole to collapse. After breaking free from the wires, the balloon experienced a sudden ascent of approximately 400 meters before entering a wooded area, where it struck tree branches and eventually came to rest on the ground. Three passengers sustained minor injuries and were transported to a hospital, while the pilot and the remaining seven passengers were uninjured.
The investigation
The CIAIAC investigation examined the aircraft's maintenance records, the pilot's experience, and the meteorological conditions. The investigation utilized GPS data, which confirmed that the vertical descent rate reached approximately 4 m/s, exceeding the normal controlled descent limits.
Investigators analyzed the operator's weather briefing process, noting that the operator relied on general weather forecasts from the previous day. While these forecasts did not explicitly prohibit flight, they lacked the precision of specialized aeronautical meteorological services. The investigation also reviewed the aircraft's flight manual, which prohibits operations in the presence of cumulonimbus clouds or significant turbulence.
Findings
- The primary cause of the incident was the pilot's loss of control of the balloon due to a sudden and abrupt change in wind speed (wind shear).
- The operator's weather preparation was inadequate, as they failed to consult specialized aeronautical weather sources that would have provided more accurate, up-to-date information regarding the approaching storm front.
- The pilot failed to terminate the flight operations as soon as the presence of approaching storm clouds became visible on the horizon, as required by the aircraft's flight manual.
- The aircraft's weight at takeoff was within the manufacturer's approved limits.