What happened
On June 10, 1997, a private Bell 206B Jet Ranger, registration HB-XXI, was engaged in a photography flight near Blauen, Switzerland. The pilot had picked up a passenger, a professional photographer, to capture aerial footage of the pilot's newly constructed home. After flying over the Rhine and approaching the village at approximately 2,000 feet, the pilot performed a hover near the residence to allow the passenger to take photos through an open window.
During the maneuver, the passenger needed to change film, prompting the pilot to fly toward the Strängenfeld area to land. Once the film was changed, the pilot decided to abort the landing and initiated a go-around with a left-hand climbing turn. During this maneuver, the helicopter suddenly began rotating clockwise around its vertical axis while simultaneously descending. The pilot was unable to arrest this yawing motion using the pedals and eventually reduced collective pitch to mitigate the descent. The aircraft struck a downward-sloping meadow, causing the helicopter to capsize.
The investigation
Investigators examined the wreckage of the HB-XXI and found no evidence of pre-existing mechanical defects. While the tail rotor, gearbox, and blades showed damage, all such issues were determined to have been caused by the impact with the ground or subsequent contact with the main rotor blades. The aircraft's maintenance records were found to be in order.
The investigation also reviewed the pilot's experience and the environmental conditions. At the time of the accident, weather conditions were favorable, with high visibility and light winds. The investigation noted that while the pilot held a valid private license, his overall flight experience was limited, specifically regarding hovering operations out of ground effect (HOGE).
Findings
As the pilot increased power to initiate the go-around, the torque produced by the counter-clockwise rotating main rotor increased. Because the aircraft was moving at a low forward speed, the vertical stabilizer provided insufficient aerodynamic damping to counteract this torque. The pilot failed to apply sufficient left pedal pressure to compensate for this increased torque, leading to an uncontrolled clockwise yaw. The pilot's attempt to reduce pitch was performed too late and at too low an altitude to prevent the impact.
Safety action
- Loss of directional control due to improper pedal usage during a go-around.
- Limited flight experience of the pilot.