MD Helicopters MD520N crash near Ferlach, Austria

A Glock GmbH MD Helicopters MD520N NOTAR (OE-XGG) began rotating clockwise uncontrollably after lifting off from a paved area surrounded by halls and walls within the Glock factory compound in Ferlach. The pilot could not stop the rotation after two to three revolutions and attempted to land, resulting in a harder than usual touchdown and substantial damage. No injuries. The UUS investigation found no technical defects but could not rule out aerodynamic effects from the surrounding buildings affecting the tail rotor effectiveness.