Gulfstream EVS

Freeman's no superhuman, although he's a former U.S. Navy Pax River test pilot and combat veteran. As head of Gulfstream's Enhanced Vision System development program, he was flying Gulfstream V serial number 564, equipped with a proof-of-concept EVS that enabled him to see the runway lights far beyond unaided visual range. EVS also helped Freeman taxi N664GA to the static display in the prevailing poor visibility conditions with greater safety margins because he could see more of the taxiway lights than without the EVS.

Slated for certification in early 2000, Gulfstream's EVS uses a Kollsman-OpGal, dual-band, cryogenically-cooled IR camera that has virtually double the "vision" of human eyes. That's because "water vapor and infrared don't mix" according to Freeman. Clouds and fog that scatter visible light have much less attenuation effect on IR, according to Freeman.

The dual-band IR camera is fine-tuned to see the 1.2 to 2.2 micron IR emissions of incandescent runway and taxiway lights. Notably, IR accounts for 70% of the energy emitted by such lights, according to Freeman. The IR camera also is fine-tuned to sense three to five micron "black body" radiation, frequencies emitted by objects at night. As a result, the camera can see runway lights, terrain, pavement, trees and obstructions.

The IR camera image is display on the optional Honeywell-GEC Marconi HUD 2020 head-up display in the cockpit, along with primary flight data, a flight path vector and ILS guidance cues.

Customers want EVS, according to Freeman, because it has the potential to make available 2,300 more airports when the visibility is poorer than Cat. I minimums. Why? Many times EVS will allow the pilots to see an image of the runway lights and runway environment in the HUD one-half mile from the airport even though the unaided eye can see no farther than one-eighth to one-quarter mile.

The cost of EVS "will be less than $500,000" according to Freeman. Four fifths of Gulfstream's customers order HUDs and most want EVS, Freeman claims. He believes that the system is so intuitive that only four hours of ground training, two hours of day flying and two hours of night flying will be needed to train crews. In contrast, only 5% of Gulfstream operators use the aircraft's Cat. II ILS capabilities because of the cost and complexity of maintaining Cat. II qualifications.