What happened
On 14 January 2019, at approximately 11:34 UTC, a Sokol W-3A helicopter was performing an aerial inspection of high-voltage power lines near Bürglkopf, Austria. The mission, conducted by an electricity network operator, aimed to inspect the lines and clear snow from lateral trees following heavy snowfall.
The flight proceeded along the power line route at an altitude of approximately 15 to 20 meters above the treetops. While flying near the Almgasthof area, the pilot experienced an abrupt drop in engine performance and was unable to maintain altitude. The pilot initiated an emergency landing on the western side of the Almgasthof. During the touchdown, the main rotor blades struck a birch tree, causing severe damage to the blades and the tail rotor. The impact also caused damage to a nearby house facade. The crew, consisting of the pilot, a flight assistant, and a passenger, sustained two serious injuries and one fatality.
The investigation
The investigation focused on the sudden loss of power and the mechanical state of the aircraft. Investigators examined the engine anti-ice system, the fuel supply, and the physical condition of the engine components. Technical analysis included audio spectrum analysis of the cockpit voice recorder and video recordings, as well as an engine test. The investigation also reviewed the maintenance history of the aircraft and the meteorological conditions at the time of the accident.