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ASN Wikibase Occurrence # 244267
Last updated: 21 October 2020
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Date:20-FEB-2018
Time:14:20
Type:Silhouette image of generic AS50 model; specific model in this crash may look slightly different
Airbus Helicopters H125
Owner/operator:Fuchs Helikopter
Registration: HB-ZAN
C/n / msn: 8268
Fatalities:Fatalities: 0 / Occupants: 1
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:Insel Ufenau, Zürichsee -   Switzerland
Phase: En route
Nature:External load operation
Departure airport:Pfäffikon
Destination airport:Insel Ufenau, Zürichsee
Investigating agency: STSB Switzerland
Narrative:
In the early afternoon of February 20, 2018, two single-seat Swiss Air Force combat aircraft took off from the Payerne military airfield (LSMP) to identify a foreign state aircraft flying along the G5 airway with diplomatic clearance. The two combat aircraft were F/A-18C, registered as J-5015 and J-5018 and bearing the radio call signs "Hammer 21" and "Hammer 22". The mission had been ordered by the Chief Air Defence (CAD) at the Air Force Operations Centre.
Once the foreign state aircraft had been identified, the two F/A18C pilots carried out a prepared navigation course at the command of CAD. The crews remained in constant radio contact with the tactical command center "Batman" in the Air Force Operations Center for traffic information about other aircraft. The route led at an altitude of about 1000 ft AGL over Thun, Bern, Burgdorf, Emmen, Zug, Lake Zurich, the Linth plain and Lake Walen all the way to the Grisons.
From about 2 p.m. onwards, the pilot of the helicopter AS 350 B3, registered as HB-ZAN, carried out material transports as underload using 50 m load rope between the port of Pfäffikon (SZ) and the island of Ufenau in Lake Zurich. The pilot of the HB-ZAN was familiar with the conditions on site and had previously flown several hundred rotations in favor of this construction site. At 14:09:30 the crews of the F/A-18C received a traffic notice from "Batman" regarding a visual flight in the Hirzel region. The unidentified aircraft, a white, single-engine shoulder wing aircraft, was first detected by the F/A18C crews with on-board radar and shortly thereafter visually. Subsequently, the two F/A-18Cs swerved slightly to the north over Lake Zurich and flew around the light aircraft. The ground speed (GS) of the F/A-18C in this phase was about 355 kt, the flight altitude about 2400 ft AMSL. The pilots did not receive any further traffic information until the return flight to Payerne, which took the same route as the outbound flight. However, these instructions were not related to the serious incident. According to the crews of the F/A-18C, visibility in the Wangen-Lachen region was between 5 km and 10 km. The cloud base was about 1200 ft to 1500 ft above ground.
Immediately after the pilot of the HB-ZAN had dropped another transport load on the island of Ufenau and accelerated with the helicopter again in the direction of the pick-up point, his flight assistant, who was at the pick-up point in the port of Pfäffikon SZ, alerted him by radio to two F/A-18s approaching from the west across Lake Zurich. The HB-ZAN pilot saw the two F/A-18s in front of him, which, according to his information, crossed his flight path at a distance of between 250 m and 500 m from west to east and about 100 m higher. The switched-on Flarm in HB-ZAN did not give any warning. Both the transponder and the aircraft radio were switched on. The airfield frequency of the airfield Wangen-Lachen (LSPV), located about 7 km to the east, was set. According to the helicopter pilot, the sky was cloudy and visibility was about 10 km in diffuse haze. On the military radar system FLORAKO the flight paths of the two F/A-18Cs could be seen. At 14:11 they flew at an altitude of 2400 ft AMSL and with a speed over ground of 355 kt in eastern direction between the island Ufenau and Pfäffikon SZ. The crews of the F/A-18 never had radar or visual contact with the HB-ZAN at any time. Since no traffic in the Ufenau region was visible on the radar screen of the FLORAKO, no traffic information concerning the HB-ZAN was transmitted to the crews. The participating aircraft continued their flight uneventful.

The serious incident, in which two fighter planes and a helicopter came dangerously close, can be attributed to the fact that the crews of the fighter planes could not recognize the helicopter either visually or by technical means. In addition they received no traffic information regarding the low-flying helicopter, as it was moving below the radar cover of the FLORAKO .
During this investigation it was once again determined that the two Boeing F/A 18C fighter aircraft involved in the serious incident did not have any warning systems for prevention of collisions. The reason is that for the operation of state aircraft have special permits that allow them to dispense with safety equipment. This lack of equipment poses a considerable risk, especially for low-flying at high speed through airspace used primarily for civil purposes. for all airspace users.

Sources:

STSB

Accident investigation:
cover
  
Investigating agency: STSB Switzerland
Status: Investigation completed
Duration: 2 years and 8 months
Download report: Final report


Revision history:

Date/timeContributorUpdates
21-Oct-2020 12:06 harro Added

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