Accident Overview
On 27 November 2009, the Czech investigation authority ÚZPLN received a notification about a helicopter that was damaged during a landing in terrain near the village of Brandov in the Krušné hory mountains. The helicopter, a Robinson R44 Raven I registered OK-STE (serial number 1358, built in 2004), was being operated by LPS letecké práce a služby s.r.o. for a private flight under visual flight rules (VFR) without a flight plan. The pilot, a 29-year-old male with a private helicopter pilot license (issued April 2009) and a total flight experience of 80 hours (all on the R44), was the sole occupant and was not injured.
Flight and Landing
The flight departed from LKRO airport at approximately 13:05 UTC. The pilot flew westward, then climbed towards the ridge of the Krušné hory near Rudolice v Horách. After about 40 minutes, he arrived at a pre-arranged landing area (a clearing called "Waltrovka" in the game preserve) with dimensions 30x100 m, oriented northwest. The pilot performed a flyover to assess wind direction by observing tree tops. After a left flyover, he initiated a right turn to align into the wind. He then felt a sudden descent, which he described as a strong wind gust ("podfouknutí silným poryvem větru"). Despite maximum collective input and increased engine power, the helicopter continued to descend. To prevent rotor overspeed, he reduced collective and adjusted cyclic for landing. At about 6 m above ground, he levelled the helicopter, and at 2 m he pulled collective to stop descent. The helicopter landed hard, with the main rotor blades striking nearby trees. The pilot did not notice the blade contact. After touchdown, he disengaged the clutch, switched off the master switch, closed the fuel valve, and exited. The final landing spot was about 350 m from the intended area, approximately 10 m below the ridge level on the windward side.
Aircraft Damage
The impact and contact with trees caused damage to the main rotor blade tips (0.9-1.0 m from ends), left and right skid tubes, and deformation of the fixed tail surfaces. Subsequent inspection at the operator's facility revealed deformation of the rear fuselage bulkhead due to reaction forces from the skids. The helicopter had a total time of 889:00 hours and 2587 landings. Maintenance was performed on 30 September 2009 at 885:12 hours, and no defects were reported on previous flights (18 and 23 November 2009). The maximum takeoff mass (1089 kg) was not exceeded; fuel tanks were full at departure.
Meteorological Conditions
According to a meteorological assessment by the Czech Hydrometeorological Institute, weather conditions at the time included surface wind from 230-260° at 25-35 kt with gusts 40-50 kt. Wind at 2000 ft AGL was 230°/30-35 kt, and at 5000 ft AGL 240°/45 kt. Visibility was over 10 km, with few cumulus clouds at 5000-6000 ft AGL. Moderate to severe mechanical turbulence was reported. The intended landing area had no equipment to measure wind direction or speed.
Investigation
The investigation was conducted by a commission of ÚZPLN. Technical inspection found no pre-existing mechanical issues that would have contributed to the accident. No flight recorders were installed. The pilot's alcohol test was negative. The investigation focused on the meteorological conditions and the pilot's handling during the landing approach. No probable cause was formally stated in the available report excerpt.