What happened
On 27 May 2010, a Robinson R22 Beta II helicopter, registration HB-ZHB, was conducting a VFR training flight near Sitterdorf, Switzerland. The flight, intended to maintain proficiency during a break in the trainee pilot's regular instruction, included several maneuvers such as off-airport landings and low RPM recovery.
During the flight, the flight instructor initiated an autorotation exercise by closing the twist-grip. While the trainee pilot initially responded correctly by adjusting the collective and cyclic, the subsequent approach to the landing site lacked a critical maneuver. As the helicopter approached the terrain, the trainee pilot failed to initiate a flare to reduce the rate of descent and forward speed. The flight instructor, realizing the error too late, took control of the aircraft to attempt a controlled impact; however, the helicopter struck the ground with significant vertical and horizontal velocity, resulting in a rollover. Both occupants sustained minor injuries.
The investigation
The investigation examined the flight history, the training status of both crew members, and the mechanical state of the aircraft. It was established that the trainee pilot had completed 2/21 lessons toward a commercial license with a different instructor, while the flight instructor was performing a non-standard training flight to bridge a gap in the student's schedule. The investigation also noted that the aircraft had exceeded its manufacturer-specified maximum operating time before its next required overhaul.
Findings
- The primary cause of the accident was that the flight instructor did not intervene in a timely manner during the autorotation exercise.
- The trainee pilot failed to execute the necessary flare to transition into the landing phase.
- The flight instructor held inaccurate expectations regarding the trainee pilot's flying proficiency.
- The flight instructor had not practiced autorotations in the Robinson R22 Beta II for several months.
- The trainee pilot had not practiced the specific maneuver since February 2010.
- There was a lack of communication between the instructors regarding the trainee's progress and the nature of this specific flight.