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ASN Wikibase Occurrence # 208162
Last updated: 29 November 2020
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Date:24-MAR-2018
Time:09:31 LT
Type:Silhouette image of generic EC35 model; specific model in this crash may look slightly different
Eurocopter EC 135T1
Owner/operator:Air-Glaciers
Registration: HB-ZIR
C/n / msn: 0105
Fatalities:Fatalities: 0 / Occupants: 2
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:St. Bernhard -   Switzerland
Phase: Take off
Nature:Ambulance
Departure airport:L’Hospice du Grand-Saint-Bernard
Destination airport:Sion (LSGS)
Investigating agency: STSB Switzerland
Narrative:
In connection with the rescue of an avalanche victim, the flight operation company was commissioned with several flights on March 24, 2018. The EC135 T1 rescue helicopter involved in the accident, registered as HB-ZIR, was deployed on this mission during three flights on the Col du Grand St-Bernard.
During the third flight, a mountain guide and an avalanche dog handler were unloaded together with the dog in the parking lot next to the hospice shortly before 09:30 am. Afterwards the return flight to Sion (LSGS) was planned. On board were the pilot and the flight assistant, who was also a trained paramedic.
The pass Grand St.-Bernard was located at the forehead of layered clouds, which penetrated as a foehn wall through the incision in the terrain into the Val d'Entremont and disintegrated east of the pass summit. Visibility was diffuse in low-lying clouds with a base that at times was only 100 ft above ground. The wind blew from 280 degrees with 15 kt and gusts around 20 kt. Due to the diffuse visibility conditions, the pilot chose as a reference point for takeoff a traffic sign which protruded from the snow about 140 m away and seemed to be suitable for this purpose.
Shortly after 09:30 am HB-ZIR took off and the pilot checked various parameters in hover flight. After all technical parameters had been checked by the pilot, the rescue helicopter took off towards the mentioned reference point in slow forward flight. The crew estimated the speed analogous to a running person. Shortly afterwards, the flight assistant noticed that the machine was approaching the ground. He then shouted to the pilot, who was focused on his reference point, to pull the machine up. But before he could react, HB-ZIR collided with the ground and overturned in the snow. The main rotor cut through the tail boom and three of the four rotor blades were separated from the main rotor head. The helicopter came to a standstill on the left-hand side in the direction of flight on rising terrain. The occupants remained uninjured. After the pilot had shut down both engines, the two crew members evacuated the wreckage. Various people rushed to their aid immediately.

Conclusions: There is no evidence of any technical limitations that could have caused or influenced the accident.
The accident, in which the helicopter collided with the ground during slow forward flight, is due to the fact that the pilot did not recognize the helicopter's approach to the terrain during take-off over a referenceless snow cover in diffuse and low-contrast visibility conditions.

Sources:

www.rro.ch
http://www.20min.ch/ro/news/romandie/story/Catastrophe-evitee-malgre-une-avalanche-et-un-crash-21285593#showid=238411&index=undefined
http://aerossurance.com/helicopters/hems-ec135-cfit-lo-viz-takeoff

Accident investigation:
cover
  
Investigating agency: STSB Switzerland
Status: Investigation completed
Duration:
Download report: Final report
Location

Media:


Images:

Photo of HB-ZIR courtesy AirHistory.net


Sion (LSGS / LSMS / SIR)
8 February 2018; (c) Joop de Groot

Revision history:

Date/timeContributorUpdates
25-Mar-2018 07:23 Copi Added
25-Mar-2018 22:53 Iceman 29 Updated [Time, Destination airport, Source, Embed code, Narrative]
26-Mar-2018 16:14 Aerossurance Updated [Nature, Embed code, Narrative]
29-Oct-2020 20:20 harro Updated [Time, Phase, Departure airport, Destination airport, Narrative, Category, Accident report]
14-Nov-2020 10:06 Aerossurance Updated [Departure airport, Source, Embed code, Narrative, Accident report]

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