Wire obstacles or strikes present a significant danger to helicopter operations, according to a recent United States Helicopter Safety Team (USHST) analysis into the dangers of low-altitude flight. According to the report, approximately 16 percent of all helicopter accidents have been attributed to wire or obstacle strikes. Seventeen percent of those accidents resulted in fatalities. Because helicopters spend the majority of their flight time at low altitude, wires or other obstacles can be difficult to identify, especially in poor weather.
Wire-strike protection systems, more commonly called “wire cutters,” help prevent helicopter accidents. These tools, attached to the front of some helicopters, can cut through undetected wires that might sneak up on an unsuspecting pilot. Another laser-driven system detects not only the wires themselves but also whether or not those wires are carrying electrical current. Hazards meteorological evaluation towers (MET)—slender, hard-to-see structures often supported by nearly invisible guy-wires—pose yet another threat to helicopter operations. Because they often stand just under 200 feet in height, they are not required to comply with FAA obstruction-marking, requirements making them even more difficult for helicopter pilots to identify. The USHST says helicopter threats can be reduced if crews maintain maximum altitude for as long as possible and also use conservative routes that might only add a few minutes to a trip.