Swiss Investigation of 2016 Paraglider and Helicopter Wake Turbulence Incident (HB-ZRW)

Incident Overview and Aircraft Details On June 23, 2016, at 16:45 local time, a student paraglider was seriously injured in Wasserauen, Gemeinde Schwende (AI), Switzerland. The incident involved an Ozone Mojo 4 S paraglider and an AW109SP helicopter registered as HB-ZRW. The helicopter was operated by Schweizerische Luft-Ambulanz AG (Rega) for a commercial rescue mission. The paraglider pilot was a Swiss citizen born in 1994, with 47 total flights, 39 of which were on the accident model. The helicopter pilot was a Swiss citizen born in 1972, holding an EASA Commercial Pilot Licence (Helicopter) issued by the Federal Office of Civil Aviation (BAZL), with 7,750 total flight hours and 730 hours on the AW109SP type. ## Operational Context and Sequence of Events On the afternoon of the incident, active paragliding operations were underway near the Wasserauen landing site. A flight instructor from Flugschule Appenzell briefed 16 students, including the injured student (Student A) and another student (Student B). The students launched from the Ebenalp mountain station. Simultaneously, a Rega crew based in Untervaz (LSXU) was dispatched for a rescue mission in the Dürrschrennen area southwest of Wasserauen. Two hikers required extraction via the helicopter's rescue winch. The AW109SP (HB-ZRW) departed Untervaz at 16:11. During the approach, the crew observed numerous paragliders in the area. The pilot landed at an intermediate site near Alp Hütten at 16:32 to allow the doctor to prepare the hikers for winch extraction. ## Contributing Factors and Probable Cause At 16:39, the helicopter departed the intermediate site to retrieve the doctor and the first hiker. The pilot flew a continuous descent along the valley center toward a drop-off site northeast of Wasserauen station. During this phase, the pilot communicated with the helicopter crew member (HCM) and a rescue specialist (RSH) on the ground regarding the paraglider traffic. The RSH reported that paragliders were at a higher altitude and did not perceive a hazard. Student A and Student B were on final approach to the Wasserauen landing site. Student A, who was slightly higher and behind Student B, entered the helicopter's wake turbulence. The student lost control and fell, resulting in serious injuries. The helicopter was not damaged, and there was no third-party damage. The Swiss Transportation Safety Investigation Board (STSB) determined the probable cause was the student paraglider falling after entering the wake turbulence of the helicopter. Contributing factors included the helicopter's approach path and landing site selection, the student's decision to maintain the approach path, and the lack of coordination between the rescue mission and paragliding activities. A systemic cause was identified as the lack of awareness regarding wake turbulence hazards by both the helicopter pilot and the paraglider.