No more flying blind
See in the dark? See through fog and clouds? All of this is possible using today's enhanced vision system (EVS) technology. In fact, EVS is now available as an option on several large business jets, many special-use helicopters, and a tiny but growing number of light general aviation aircraft. These systems use infrared sensors to detect the minute amounts of heat given off by terrain and obstacles, and are based on the forward-looking infrared (FLIR) systems used by the military since the late 1960s. Another, newer enhanced vision technology uses highly refined, narrow-beam radar pulses for better resolution. These so-called "millimeter-wave radars" can even let pilots see power lines shrouded in fog, or identify individual structures. But because of their high cost, millimeter-wave radars are mainly installed in military aircraft.
EVS, however, is making big inroads in general aviation. The benefits to safety are obvious. EVS promises an end to controlled flight into terrain accidents because pilots would be able to see the terrain ahead, even if it's enveloped in fog. Night approaches to poorly lit runways would be infinitely safer because the entire runway would be "lit up" by the tarmac's heat signature.
Another technology uses GPS database information to give pilots views of their surroundings. Its information is shown on primary flight displays or multifunction displays.
Virtually all current EVS installations involve a heads-up display (HUD) — yet another device with roots in the military. HUDs have been around for decades, customized for weapons delivery as well as depicting a wide range of flight instruments. With the new generation of fighters in the 1970s, and the need for more precise low-level attack missions during the Vietnam War, HUDs then added FLIR and targeting algorithms.
The traditional HUD screen is just aft of the windshield, and the pilot sees the EVS imagery through the screen as he looks forward. Now initiatives are under way to make EVS work on electronic flight bags, multifunction displays, and primary flight displays. This obviates the need for expensive military-style, forward-looking displays. In the future, expect to see more EVS — and HUD — equipment on general aviation airplanes. The value of this gear during the critical transition period from instrument flight to prelanding flare alone should make it a very desirable addition to the growing GA technology arsenal.— TAH
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