What happened
On 4 March 2022, a Sikorsky S-92A, registration G-MCGY, was performing a search and rescue operation at the Derriford Hospital helipad in Plymouth, Devon. During the landing and subsequent departure phase, the intense air currents generated by the helicopter's rotors—known as downwash and sidewash—interacted with the surrounding environment. The powerful airflow caused debris or objects to be displaced, leading to a tragic incident where one person was fatally injured and one person sustained serious injuries.
The investigation
The AAIB investigation examined the operational procedures at the hospital helipad, the design of the landing area, and the physical characteristics of the aircraft. Investigators reviewed CCTV footage, flight recorder data, and the hospital's risk management protocols. The probe looked into how the helipad was planned, specifically whether the potential for downwash to affect nearby pedestrian areas and car parks had been adequately mitigated. The investigation also assessed the effectiveness of safety signage and the adequacy of the hospital's risk assessments regarding the movement of people and objects in the vicinity of the landing site during helicopter operations.
Findings
- The Sikorsky S-92A is a high-density rotor disc aircraft, which produces significant downwash that can reach high velocities near the ground.
- The downwash and sidewash produced by the aircraft's rotors were powerful enough to impact the surrounding pedestrian and vehicle areas.
- Inadequate mitigation of downwash hazards in the design and management of the hospital helipad environment contributed to the accident.
- The hospital's risk assessments did not sufficiently account for the potential for downwash to cause harm to individuals in nearby car parks or pedestrian zones.