What happened
On 5 November 2018, a RotorWay Exec 162 helicopter, registration F-WSPM, was performing a local flight near Saint-Pierre, Saint Pierre and Miquelon. The flight was part of a program to fulfill the requirements for a Special Airworthiness Certificate for a kit-built aircraft.
The pilot, accompanied by a passenger, initially hovered near a photographer at a private helipad. Following a period of hovering, the pilot began a climb involving a left-hand turn and forward movement. During this initial climb, at an altitude of approximately ten meters, the helicopter experienced a sudden left bank and began to side-slip. The aircraft lost altitude and the forward left section of the airframe struck the ground. The impact caused the helicopter to bounce and overturn, ultimately coming to rest on its right side. The accident resulted in one fatality and one injury.
The investigation
The BEA examined the wreckage at a hangar in Saint-Pierre. While the flight controls showed no anomalies, investigators found that the engine's drive belts had jumped from their housings due to an overtorque caused by the rotors being suddenly blocked upon ground impact.
Meteorological analysis revealed that while airport winds were moderate, the proximity of nearby hills and trees likely created local turbulence or vortex phenomena. The investigation also reviewed the aircraft's weight and balance configuration. It was noted that the helicopter was missing its required 12 kg counterweight, having been replaced by a much lighter 2.5 kg battery. This configuration, combined with a full fuel load and a passenger, placed the center of gravity at an extreme forward-left position.
Findings
- The primary cause of the accident was a sudden left-hand roll triggered by a wind gust while the aircraft was in a tailwind condition.
- The helicopter's center of gravity was at the edge of the flight envelope, which likely limited control effectiveness and required much more rapid pilot inputs to recover.
- The use of a "yaw" take-off technique in turbulent conditions, combined with the positioning of the aircraft for photography, restricted the available escape paths.
- The pilot's relatively limited experience with this specific aircraft type may have contributed to an insufficient response to the sudden roll movement.