FLIGHT TESTS OF the Honeywell/GEC-Marconi HUD 2020 head-up-display (HUD) system are due to begin on a Gulfstream IV in February, following the delivery of flight-test equipment from GEC late in 1995.

A pre-production HUD 2020 and newly developed Honeywell symbology are still being flight-tested on the US avionics manufacturer's Cessna Citation III testbed, but the system being installed on the GIV this month will clear the way for certification in 1996. The system will be cleared for Category II landing conditions on the GIV and GIV-SP around the third quarter of this year, with certification on the GV scheduled for 1997.

Gulfstream, which is taking over the GIV HUD supplementary type certification (STC) and "...rolling it into a GIV-SP STC for Cat II and GV for Cat II", will also have the programme lead for certification to Cat III. Gulfstream believes that this goal may be achievable by December 1996 if it can successfully combine a cooled forward-looking infra-red (FLIR) visual system with the HUD. "By the end of 1996, we intend to be well on our way to Cat IIIa minima," says the company.

Gulfstream believes that a cooled IR system, possibly supplanted at a later stage by a passive millimetre-wave detection system, will be adequate for Cat IIIa clearance. The company says that it is "....committed to go forward on an enhanced-vision programme. We know our customer base traditionally operates from less-developed airports, so we want to give them the capability to operate from those airports at lower minima."

Honeywell, meanwhile, is pursuing its own uncooled FLIR-sensor programme for business aircraft, using technology derived from its military business. Although Gulfstream believes that the technology does not have "...the performance we need", Honeywell believes that the cheaper, uncooled, alternative would still bring operational benefit. "We're pursuing something that would simply turn night into day. The Honeywell system will be cheaper, and we intend to put it into a Citation testbed in 1996," says the company.

Honeywell is optimistic that the HUD development will provide safety as well as operational benefits. "The FlightSafety Foundation says that, of a little over 1,000 accidents, a HUD might have prevented more than 31% of them," it says. One of the main new-symbology developments is a military-like flightpath vector symbol. "This is one of the keys of the new HUD. It's an aiming point that tells you exactly where the aircraft is heading," says Honeywell.

The symbology is also complementary to the existing head-down electronic-flight-instrument system symbology on current Gulfstream aircraft, with the HUD being driven by the same DC-884 integrated display controller.

Source: Flight International