Wire Strike Protection System

The Wire Strike Protection System ( WSPs or cable cutter; German: Kabelkappsystem; uncommon German translation: system protection in case of wire collision; wire protection system ) is a safety device ( passive safety system ) for helicopters.

General

The WSPs provides coverage for accidents caused by collision with cables (eg overhead lines, cable cars, bungee cords on towers ). If the pilot will see a steel cable too late and it come to a dangerous encounter between a helicopter and cable, then you can save the WSPs life. The system was developed by Bristol Aerospace.

Technology

The WSPs consists of three parts: a sharp-edged blade above and below the helicopter nose (lower wire cutter, upper wire cutter ), which are under the rotor mounted ( on the cab roof ) and under the cell and a deflecting rail for reinforcement and as a guide rail for the impacting wire ( windshield deflector ). This rail is mounted vertically on the center strut of the helicopter nose. She heads the wire into the upper or lower wire cutter, which then cuts the bouncing wire.

In some systems ( for example, when OH -58 helicopter ) the deflecting rail on the windscreen is abrasive designed so that the wire while sliding over the deflecting rail partially wear through and so already weakened before it in the upper or lower blade reaches.

This safety equipment is also known as Wire Strike Kit. It is not obligatory for most helicopter operations by the manufacturer or legislators, but just increased for helicopters with special tasks in low altitudes security. The problem is that there are special hardened wire cutter, which are relatively expensive. In addition, the Wire Strike Protection System can not be installed on all types of helicopters.

In 70 to 80 % of the accidents caused by wire rope wire rope slips on the top side of the helicopter, as the foremost point of the helicopter nose is usually relatively low. There then pulls the wire rope from the rotor. The WSPS pilot survives contact with a (single ) wire with 95% probability. But should he have contact with 2, 3 or 4 wires, then its probability of survival decreases to 75 %, 50 % and 25% respectively.

Identification of obstacles

Regardless of the equipment of the helicopter with WSPs overhead lines near the motorway with red balls marked (English to German wire marker: cable markers) in order to improve their visibility for pilots with reduced visibility. Especially rescue helicopter navigate during their missions along the highway, on which they then have to land. In Germany, this scheme is in the general administrative provisions for the identification of obstacles to aviation section 2 "Days labeling " in section 5.4; and in Austria by the Civil Aerodrome Regulation (ZFV 1972) Section 6 "Marking of obstacles " in § 68 regulated.