Taking Synthetic Vision To The Next Level

By John Croft
Source: Aviation Week & Space Technology

Other elements of the display that are new or unique include a track-centered boresight, meaning the synthetic view is centered on the direction the aircraft is tracking versus the direction the nose is pointing (heading-centered). Though the EASy 2 flight deck nominally uses heading-centered synthetic vision, Honeywell has found that the track-centered method makes for a smoother presentation.

Nearing the airport, the runway approach indicator provides a very intuitive target to line up for the approach-and-sense motion, or flow, toward the runway end. It features a cyan box outlining the synthetic runway, and within 10 nm of the runway end it includes a four-light geometric precision-approach-path indicator (PAPI) at the front left-side of the box. When on the glideslope, the runway outline has the correct trapezoidal shape (see diagram, above) and PAPI shows two white lights to the left and two red lights to the right. Too high and all the lights go white; two low and all the PAPI lights are red.

At 10 nm from the runway end, a conformal lateral deviation indicator also appears in magenta intersecting a cyan line marking the approach path. A magenta aircraft icon shows the crab angle with respect to the course centerline.

Both features—the relative shape and location of the runway box and the PAPI—are familiar elements to pilots from their initial days in flight instruction, and were a very comfortable visual element for me on the pitch-black approach into Tucson. Pilots from their first days in the cockpit learn to roughly judge the proper vertical path for an approach by the outline shape of the runway, and to precisely trim the glidepath using the PAPI. It was no different in the Falcon, except that I had a visual image of the runway shape and the PAPI much farther from the runway than through the windscreen. With the validated position of the runway, I could place the flight-path marker on the end of the runway and be assured that is where the aircraft would end up. The flight-path marker, common on head-up display systems and legacy synthetic displays, is a predictor of where the aircraft will go based on its current dynamic state.

The system very quickly became comfortable to fly through four approaches into Tucson, with the transition between the primary flight display and the outside runway environment non-problematic at a 150 ft. decision height, or for that matter, down to 100 ft. What I could not evaluate on this night was the how the system would feel in actual instrument weather, or in a strong crosswind. Honeywell points out that the aircraft icon in the lateral guidance shows the pilot the direction where the runway will be located, and its tests in strong wind conditions have been non-problematic.

Tap the icon in the digital edition of AW&ST to fly along in a Falcon 900EX and see details of a new Honeywell synthetic vision-based avionics system, or go to AviationWeek.com/video


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