Honeywell demo shows fused SVS/EVS views
Honeywell has given the aviation world its first glimpse of a cockpit technology that developers say will change the way future pilots aviate by combining the views of a synthetic-vision database of obstacles, topography and airports with a forward-looking infrared camera on a single cockpit display.
The company wasn’t the first avionics manufacturer to explore such a concept–and Honeywell concedes that it probably won’t be the first to bring the technology to market–but nonetheless it relished the opportunity to be the first to publicly demonstrate the merging of synthetic-vision system (SVS) and enhanced-vision system (EVS) visuals on a business jet primary flight display.
Nighttime Demo Flights
Honeywell chose to reveal its progress on the developmental enhancements to its SmartView SVS by inviting aviation journalists on a series of nighttime demonstration flights last month between Arizona’s Phoenix Deer Valley Airport and Prescott Ernest A. Love Field. Flown in a company Cessna Citation Sovereign captained by chief test pilot Jary Engels, the sorties gave the trade media their first opportunity to see such an SVS/EVS presentation in the cockpit of a real airplane. The one word that most easily came to mind after the experience: impressive.
While Honeywell tempered expectations for the demonstrations with the admonition that the developmental technology was still probably five years from reaching the market, the fused SVS/EVS view that journalists saw on the demo flights seemed enticingly close to becoming a flight-deck-ready upgrade to its Primus Epic avionics system. Hundreds more hours of flight testing are needed for initial certification, and even more work lies ahead before Honeywell can realize its goal of using the technology to obtain lower landing minimums for properly equipped airplanes–but the work done so far shows immense promise.
Honeywell’s SmartView SVS gives pilots a compelling 3-D virtual look at the world ahead of the airplane, complete with guidance cues and terrain shading in colors that mimic VFR sectional charts. That presentation becomes far more convincing–and reassuring–once the EVS view is added in the center of the primary flight displays. Using special software algorithms, the EVS image from a Kollsman IR camera mounted in the nose is shaded in the same colors as the resident SVS terrain in the background, while also being “blended” with the SVS view. The technique helps to merge the SVS and EVS views into a single coherent picture that makes every flight the equivalent of a bright, sunshiny day.
Descending over northern Arizona on one of the flights, mountain peaks that could not be seen out the windshield because of the darkness were easily discernable on the PFD. The SVS and EVS views of terrain almost always matched up perfectly as mountains entered and exited the EVS portion of the display–including the subtle color shifts from brown to green as the terrain rose and fell. When the images didn’t align properly, it was usually because the real sky in the distance was darker than the virtual blue sky on the SVS display or in areas where the database’s interpretation of terrain did not mesh perfectly with the real world outside.
Still, during the majority of the demonstration flights, the SVS and EVS worlds matched one another surprisingly well. The biggest difference on the EVS portion of the display was the ability to clearly make out roads, rivers and other ground features that were not present in the SVS view.
On approach the technology seemed even more impressive. As the pilot reached to pull down the gear handle, the view on the displays automatically shifted, decluttering the flight path marker to allow more of the EVS view to be seen on the display. Once established on final, the landing runway was highlighted by a cyan-colored rectangle with a cyan course line flanked by thicker cyan dashed lines (“Paver stones,” Engels called them), highlighting the final approach course all the way to the runway threshold.
As the Sovereign reached decision altitude, a virtual gray-colored runway marked 22L morphed into (and matched extremely closely with) the real Runway 22L at Prescott Airport that appeared in the EVS window. Unlike the SVS portion of the display, inside the EVS window one could see taxiways, airport lighting including the VASI and other aircraft and ground vehicles. Developers say this real-world view on the PFD is what makes SVS/EVS blending such an important safety enhancement.
“The benefits of blending the synthetic view, which we’ve already certified, with a real-world enhanced view using sensor data is pretty obvious,” said Chad Cundiff, vice president of crew interface products for Honeywell. “You can imagine if there was a deer on the runway or truck driving across how valuable it would be to have that IR view.”
Once on the ground, the enhanced SmartView presentation changes again, this time expanding the EVS box and turning it gray to provide an improved view for taxiing at night or in low visibility. Many pilots who fly with HUD-based EVS systems say IR technology’s greatest safety benefits come while taxiing at night, especially on unfamiliar airports. Some of those same pilots complain about the limitations of IR-based EVS, one of which is that it cannot see through solid clouds or fog. But because of the way Honeywell blends SVS and EVS views, the technology can be used in clouds. In such cases, the SVS view becomes dominant even in the EVS portion of the display.
One benefit of the SVS/EVS blending technique Honeywell has developed is that it helps pilots easily pick out the height of cloud layers above and below. (Another drawback of IR-based EVS is it cannot detect LED lighting, which is fast becoming the standard at airports around the world.)
The big question now is whether the FAA will someday allow landing credits as it currently does for HUD/EVS operations. Pilots flying with HUD-based EVS are permitted to continue straight-in precision approaches to 100 feet if they can see the runway using the EVS. Honeywell is hoping to obtain a similar operational enhancement in airplanes equipped with SVS/EVS.
Cundiff noted that the FAA’s NextGen roadmap calls for the introduction of “equivalent visual operations” (intended to give aircraft VFR capabilities in IFR conditions) sometime between 2012 and 2016. Honeywell representatives are part of FAA and RTCA working groups now exploring such technologies.
Situational Awareness Improves
Perhaps the best indication of whether SVS/EVS blending will improve safety and enhance situational awareness came during a portion of the demonstration flight when Engels shut the SmartView system off. The display automatically reverted to the traditional blue-over-brown presentation of an electronic ADI. Invariably when this happens in a high-performance airplane in the mountains at night, the pilots’ immediate reaction is they want the SVS view turned back on–asap. Given the choice of an SVS view or a display featuring blended SVS and EVS, chances are very few pilots would choose the former. “Having that IR view of what’s really outside raises the comfort level at least a notch or two,” Engels said.