Incident Overview
On February 1, 2014, a two-seat Hélicoptères Guimbal Cabri G2 helicopter was involved in an accident at the Verkehrslandeplatz Augsburg (EDMA) airfield. The incident occurred during a training flight for a private pilot license. The aircraft sustained severe damage to its tail assembly and fenestron, while both occupants remained uninjured.
Flight Sequence
The flight instructor and student were conducting hover exercises in the X-Ray Area, a grassy zone south of the runway, due to delays caused by Special VFR conditions. At approximately 11:53 local time, the student was hovering at roughly two meters altitude when the helicopter began rotating clockwise around its vertical axis. Despite input on the left pedal, the rotation accelerated. After turning approximately 90 degrees, the instructor attempted to regain control but aborted a landing attempt due to nearby obstacles. The aircraft was deliberately set down on the ground, resulting in the tail striking the vertical fin.
Aircraft and Damage
The helicopter, manufactured in 2010 with serial number 1015, had accumulated approximately 1,626 flight hours. It is powered by a Lycoming O-360-J2A engine and features a fenestron for yaw control. Post-accident inspection revealed the tail boom was broken off ahead of the horizontal stabilizer, the vertical fin was sheared at the top, and the fenestron blades were damaged. The aircraft came to rest tilted backward on the grass.
Investigation Findings
The German Federal Aviation Office (BFU) concluded that the helicopter rotated in the direction of main rotor rotation. This indicated that the fenestron was generating excessive thrust for yaw control. The investigation noted that such uncontrolled rotations can occur if the fenestron blades are set to high efficiency, creating more counter-torque than necessary. No fire occurred, and no third-party damage was reported.