What happened
On April 19, 2010, a Hélicoptères Guimbal Cabri G2 was conducting a flight evaluation at Karlsruhe/Baden-Baden Airport. The purpose of the flight was to assess the suitability of the new helicopter model for student training at a flight school. The pilot, accompanied by a passenger, initially performed several circuit patterns and autorotations with no notable issues.
Following these maneuvers, the pilot intended to test the aircraft's behavior during yaw control difficulties. After completing two successful circuits, the pilot attempted a third maneuver, transitioning into a hover at the start of the final approach. During the deceleration phase, the pilot noted that the nose of the aircraft began to swing to the left. In an attempt to maintain altitude, the pilot increased the collective pitch, which inadvertently intensified the rotation around the vertical axis. The pilot did not use the pedals to correct the yaw, and the aircraft entered a series of uncontrolled rotations. After completing two full 360-degree turns, the helicopter struck the ground in a backward motion. The main rotor blades struck the terrain, resulting in heavy damage to the aircraft. The pilot and passenger were able to exit the helicopter independently and sustained no injuries.
The investigation
The BFU examined the wreckage and the flight sequence. The investigation confirmed that the tail boom, including the Fenestron drive shaft, had broken away from the fuselage, remaining attached only by the Fenestron control cable. The landing gear skids were displaced, and the main rotor blades were splintered and partially broken. There were no signs of technical malfunction; the control systems were fully connected, and oil levels were within the normal range. The pilot did not report any mechanical issues prior to the loss of control.