What happened
On May 20, 2002, at approximately 13:24 UTC, a Hughes 269C helicopter was performing an aerial photography mission near Weiz, Austria. Shortly after departing, while in a climb at an altitude of approximately 100 meters, the aircraft began to vibrate and emit a loud droning noise. This was immediately followed by a rapid decrease in the main rotor RPM.
Due to the low altitude and the terrain, the pilot was unable to perform an autorotation. In an attempt to maintain control, the pilot reduced the pitch, which briefly increased the rotor RPM. However, to clear nearby trees and reach a suitable landing site in a field, the pilot was forced to increase power, which caused the rotor RPM to drop once again. The helicopter reached the field with low rotor speed and a high rate of descent.
During the attempt at a running landing, the aircraft sank into the soft, uneven ground and entered a tilt. In an effort to prevent the helicopter from overturning, the pilot used the remaining rotor energy to upright the machine, which resulted in the aircraft rotating 180 degrees. The landing caused significant damage to the landing gear, tail boom, and main rotor blades. The pilot and the passenger were uninjured.
The investigation
The investigation focused on the sudden loss of engine performance and the rapid decay of rotor RPM. Prior to the flight, the pilot had performed refueling and hover checks, which revealed no abnormalities. Post-accident testing of the engine on June 26, 2002, showed no technical defects in the powerplant. However, an analysis of the AVGAS fuel used in the aircraft revealed that the fuel was contaminated with water and organic material.