What happened
On September 29, 2005, a Robinson R22 Beta II, registration HB-ZGS, was conducting a flight instructor skill test near Limpach, Switzerland. The crew consisted of a candidate flight instructor, acting as the pilot-in-command, and an examiner, acting in the role of a student pilot.
During the final phase of the assessment, the crew was performing low-altitude hovering exercises. The examiner, simulating an unstable student, intentionally released the cyclic control without warning to provoke a reaction from the candidate. This sudden movement caused the helicopter to tilt and slide to the left. As the left skid made contact with the ground, the aircraft entered a dynamic rollover, resulting in the destruction of the helicopter. Both crew members sustained slight injuries and were able to exit the wreckage.
The investigation
The investigation focused on the operational maneuvers and the environmental conditions during the skill test. Investigators examined the flight profiles, the technical state of the aircraft, and the weather conditions at the time of the accident.
Technical analysis confirmed that the Robinson R22 Beta II was in a healthy, airworthy condition, with no mechanical failures contributing to the crash. The aircraft's weight and center of gravity were within prescribed limits. Meteorological data showed winds of approximately 10 knots with gusts up to 20 knots, which, while present, did not exceed the operational limitations defined in the pilot's operating handbook for the pilot's experience level.
Findings
- The examiner's decision to suddenly release the cyclic control created an uncontrollable flight condition.
- The sudden loss of control led to the left skid striking the ground, initiating the pivot required for a dynamic rollover.
- The examiner underestimated the impact of the surprise maneuver and the difficulty of recovering the aircraft once the skid caught the ground.
- While the candidate had expressed concerns regarding wind conditions during the initial briefing, the actual winds were within legal limits, though the decision to proceed with the test under gusty conditions was noted.