What happened
On May 2, 2015, at approximately 17:20 UTC, a FB 34 hot air balloon, registration OK-771 and 7717, was conducting a sightseeing flight in the Český ráj region. The flight, operated by BALLOON CLUB Bílá Hlína, included the pilot, an experienced instructor, and two passengers.
After approximately 20 minutes of flight, the balloon encountered unstable air masses. The pilot, attempting to terminate the flight early and land in a suitable area near the village of Boseň, encountered a sudden and intense descent while maneuvering near a hill. Despite intensive use of the burner to maintain altitude, the pilot could not arrest the rate of descent. The basket struck a plowed field with significant force at an estimated speed of 3–4 m/s, subsequently tipping onto its side and dragging approximately 20 meters along the ground. The impact resulted in two injuries among the passengers, including a facial injury involving broken teeth and a knee injury.
The investigation
The ÚZPLN investigation examined the pilot's qualifications, the meteorological conditions, and the technical state of the aircraft. The investigation established that the pilot held valid licenses and a medical certificate, but had not flown this specific aircraft type previously. The investigation also reviewed the meteorological data from the ČHMÚ, which indicated generally favorable conditions with light, variable winds and good visibility, though some turbulence was present above 2,400 ft MSL.
Findings
- The pilot was not legally qualified to carry passengers at the time of the accident due to a lack of recent flight experience (the flight was his first after a break of more than six months).
- The pilot likely failed to realize that the envelope was insufficiently pressurized during the descent.
- The pilot underestimated the impact of changing airflow behind an obstacle, which contributed to the increased rate of descent during the landing maneuver.
- Inappropriate piloting during the landing maneuver caused the hard impact.
- The pilot's low annual flight hours and the long period of inactivity led to a loss of proficiency in handling the specific aircraft dynamics during critical phases of flight.