It's Been a Long, Long Flight for EVS, But It Will Ease Bad-Weather Landings

"This has been hard," says Gulfstream senior vice president for programs Pres Henne, "but I guess good things come hard these days."

He is talking about the Enhanced Vision System (EVS) that Gulfstream and its partners have developed for the Gulfstream V. Four years ago, Gulfstream and Kollsman were talking seriously about EVS. The program was under way by NBAA '98, with an internal goal for certification in June 1999. By NBAA '99, Gulfstream was expecting certification in early 2000. A year later, the target was certification in the first quarter of this year.

"We start certification flying next week, or the week after," Henne said in early August. "The camera seems to be performing, and we have gone through the development of special conditions with the FAA. We have the rules in hand--we think."

Gulfstream V serial number 501 will perform the certification flights, shooting 35-40 approaches by day, by night and in visual and instrument conditions. After the initial series of flights, the system should be certificated to 100-foot landing minima. After certification, the first customer aircraft could be modified late in the year.

The EVS comprises a fixed forward-looking infrared camera, based on technology developed by Opgal of Israel, which supplies IR imagery to the airplane's Honeywell/BAE Systems head-up display (HUD). Military airplanes have been using this basic technology since the 1980s.

EVS has two functions. In rain, cloud or fog, it allows the pilot to acquire the runway lights at a greater distance and complete a safe and legal landing under conditions where the onboard or airport instrument landing systems would not normally allow it.

At night or in diminished visibility, EVS is an aid to situational awareness, easily revealing traffic or obstacles on the ground and providing the pilot with a clear view of terrain around the airport.

EVS is particularly valuable to business jets, which do not have the expensive autoland systems fitted to commercial jets and often fly into smaller, unfamiliar airports with limited or no electronic landing aids.

Development has been difficult. Indeed, in the early days of EVS there were many well-qualified people who thought it was impossible, because moisture in the atmosphere absorbs most IR energy. The key to the Gulfstream system is a specially developed camera which operates at a wavelength where runway lights are most easily detected. An image-processing computer and software automatically control the system to maximize the visibility of the lights while eliminating "blooming" or noise.

The camera and computer have taken time to develop. The current production model reflects hardware and software changes that were made after tests in 1999, and which were tested on a prototype camera in 2000.

But at the same time, notes Henne, "we were setting a new precedent in terms of visual technology in the cockpit," and the company had to work with the FAA to set rules under which the camera would work. "We got down to where we were ready to certificate, and the FAA said, 'this is new and different,'" says Henne. After observing dozens of flights, in March the agency issued additional conditions. Gulfstream grumbled (expressing disagreement on the record), but complied.

It's probably an understatement to say that Gulfstream will not make a lot of money on the 35 EVS installations which have been ordered for Gulfstream Vs to date, but the company's confidence in the system's value has increased rather than diminished.

EVS, which is not even offered on any other commercial aircraft, is a standard part of the PlaneView avionics suite on the new Gulfstream V-SP.

-Bill Sweetman