What happened
On December 31, 2014, a hot air balloon, registration OK-4450, was preparing for a flight near the village of Moravské Knínice. The flight was intended as a training session for two pilots to extend their HOT qualifications. The crew selected a grassy area within an orchard for takeoff, a location characterized by rows of fruit trees and proximity to 22 kV high-voltage power lines.
During the pre-flight process, the pilot began inflating the BB 45N balloon with cold air and subsequently with hot air. The balloon was anchored to a support vehicle using a release mechanism. After the initial inflation, the pilot prematurely released the anchor mechanism before the balloon had achieved sufficient lift. A gust of wind caught the insufficiently pressurized envelope, causing the balloon to move horizontally just above the ground.
As the balloon drifted toward the nearby power lines, the instructor took command and ordered the pilot to vent the balloon. To prevent a direct electrical arc, the instructor even shut off the fuel supply and drained the lines. The instructor then exited the basket and used the crown line to attempt to maneuver the envelope over the wires at the support pole. Ultimately, the envelope draped across the high-voltage conductors. The instructor contacted emergency services to request a temporary power shutdown to safely manage the situation. No injuries were reported, and no property damage occurred.
The investigation
The ÚZPLN investigation examined the crew's statements, a witness account, and video footage recorded by a bystander. The investigation focused on the takeoff procedures, the suitability of the chosen launch site, and the decision-making process of both the pilot and the instructor. The commission also reviewed the meteorological conditions, which included light winds but significant ground-level turbulence and light snow.
Findings
- The chosen launch site was entirely unsuitable due to its small size, the presence of nearby obstacles (trees and power lines), and the prevailing weather conditions.
- The pilot failed to follow the flight manual regarding the use of the release mechanism.
- The pilot prematurely released the anchor before the balloon was sufficiently heated to maintain flight.
- The pilot did not immediately abort the takeoff by venting the balloon after the premature release, mistakenly believing that adding more heat would resolve the situation.
- The instructor failed to closely monitor the pilot's actions during the critical takeoff phase.
- The instructor reacted with significant delay, only taking command when contact with the power lines became inevitable.
- The crew did not seek permission from the landowner to use the orchard for the launch.