Wire strike protection system
The wire strike protection system (WSPS) (Developed for the OH-58 / Bell 206 in 1979) is a system of components designed to mitigate the risk of wire strikes while flying helicopters at nap-of-the-earth altitudes, as well as takeoffs and landings.
The system is mounted around the front of many U.S. Marine Corps, U.S. Navy, U.S. Air Force, U.S. Army,[1] and some civilian helicopters. The larger CH-46 and CH-47 tandem-rotor helicopters have no WSPS installed.
The WSPS appears as two guidance swords at the upper and lower front of the cabin protruding forward at 45° above and below the horizontal. In each of the inner corners to the cabin a large, fixed pair of scissors made of hardened steel is mounted whose opening angle is so small that a speedy or forced incoming steel cable is cut through.
These swords are often mistaken for radio antennas. The entire system may include upper and lower cutter assemblies, a non-electrically conductive abrasive strip wire scoring device along the center of the divided windscreen and windshield wiper protector frames to keep wires from hanging up on wiper motor shafts.[2] The WSPS is designed to channel a wire or cable into the cable cutter to score and weaken it as it travels into the cutter assembly and "cut" a wire before it can entangle the rotor system. The U.S. Army Safety Center at Fort Rucker, Alabama, claims that, in a single-wire strike, 90% survivability is achieved by using WSPS. The more wires encountered at a given time, the less likely WSPS will help the aircraft survive the encounter.
Some WSPS lower cutters have a breakaway tip in case of nose low ground impact.
References
See also
External links
- www.helicopterpage.com - WSPS (How Helicopters Work)
- Safety Study of Wire Strike Devices Installed on Civil and Military Helicopters
- Wire Strike Accidents in General Aviation: Data Analysis 1994 to 2004 – Page 33
- Wire Strike Protection System, MDHS 500 Maintenance Manual
- Magellan Aerospace Announces New Bell Helicopter Wire Strike Protection System Development