Honeywell Aerospace continues to develop improvements and add-ons to its SmartView synthetic-vision system (SVS), including a 3-D taxi system and the capability to use lower Category II landing minimums on Category I ILS and GPS-based LPV approaches. Both new features, while not yet products, offer the promise of increasing pilot situational awareness and flight safety during different phases of flight.

SmartView uses the terrain database of Honeywell’s enhanced ground proximity warning system (EGPWS) merged with the company’s head-up display (HUD) symbology to show on the pilots’ primary flight displays (PFDs) a synthetic, 3-D, daylight view of the aircraft’s flight path, the terrain ahead and the current navigational environment. SmartView is currently available on Gulfstream and Dassault business jets equipped with, respectively, Primus Epic-based PlaneView and EASy II flight decks.

Real Taxi Display on PFD

The objective of 3-D taxi is to be a “primary taxi display” for pilots, Thea Feyereisen, an engineer fellow with Honeywell’s Advanced Technology Group, told AIN. “Currently with SmartView showing on the primary flight display, after the pilot turns off the runway, the display shows the aircraft taxiing on dirt or grass,” said Feyereisen, who has been working on synthetic vision at Honeywell since the early 2000s. “What we want to do is provide the pilot with a continuous external scene of the airport area on that forward display.”

To activate the 3-D taxi image, the pilot would need to select the taxi display via a switch, and would have the choice of two views. “The primary, or pilot’s, view, is an egocentric view,” Feyereisen explained. It shows a synthetic view of what the pilot would see through the windshield. “The pilot can also select an exocentric, or third-person, view,” she said, “which is almost as if you had a camera on the tail of the airplane looking forward and down. The aircraft is shown in the center of what we call the ‘hockey puck.’”

To provide better situational awareness of the taxi display, the researchers modified or removed much of the standard HUD symbology that SmartView shows in flight, and added other symbols of relevance to taxi operations, placing them where they can easily be seen. For example, instead of showing taxiway signs in the grass next to the runway, as they are in reality, the researchers placed the taxi identifiers in the center of the taxiways in the 3-D taxi display. Barriers or gates across runways in the display are meant to remind pilots they need a clearance before crossing. If controller pilot datalink communication (CPDLC) is coupled to 3-D taxi, the taxi display will graphically show, using a magenta line, the taxi clearance received and indicate a closed gate at the limit of the clearance. This, of course, could help reduce the chance of an incursion onto an active runway.

The 3-D taxi feature uses that same database that Honeywell uses to display 2-D airport maps. In this 2-D model the heights of most the buildings on the airport are the same. The researchers decided not to change this. “One of the things we have found is that we don’t need to show the actual heights of 3-D structures on the airport on the taxi display,” Feyereisen said. “Pilots don’t need this information to taxi safely.” She added that Honeywell also does not want the buildings in the database to be above a certain height. “We envision including ADS-B surface targets in this database, so we want to have visibility to the targets on the other side of terminal and other buildings. So we kept a low, fixed height for most of the buildings,” she said.

3-D taxi is meant to be a companion to Honeywell’s 2-D airport map, not a replacement. “3-D taxi gives more of a tactical view of the airport area, while the 2-D map is more a strategic view. Pilots still need that strategic view,” she said.

When will the 3-D-taxi system reach the market? According to Feyereisen, the system has moved out of the research phase and is now in Honeywell’s product phase. “The 3-D taxi product is currently targeted for SmartView-equipped aircraft, so it would go to Primus Epic [PlaneView and EASy] customers first and would be an add-on, because it adds a new database and capability. It could be included as standard equipment for a new aircraft for retrofit.”

She said the system could also run on Honeywell’s Primus Apex product line, now on the Pilatus PC-12 NG and Viking Twin Otter Series 400. “It’s just software, so fits on multiple display sizes,” she said. “You just need a database and graphics processors.”

Heads-down Cat II Minimums

The promise of Honeywell’s SmartView Lower Minimums (SVLM)–to lower the landing minimums of Category I ILS and GPS-based LPV approaches to 150 feet agl ceiling and 1,400-feet RVR visibility without changing or adding navigation equipment on the ground–sounds almost too good to be true. But the company can back up this promise with several years of research and impressive flight- and simulator-test results this year.

“We have been engaged with the FAA since 2010 in a proof-of-concept program, Feyereisen explained. “This helps establish certification requirements, where there may not be any that cover this sort of technology. We provided the FAA with the concept of operations, the concept of system design and a system safety analysis.” The company expects to get feedback from the FAA prior to moving SVLM into “productization.”

“The crowning moment of the proof-of-concept program was our test flights,” Feyereisen told AIN. “We tested on two different platforms, one on aircraft and one on simulator. We used Honeywell’s Dassault Falcon 900EX EASy II. We flew with nine pilots from the FAA and EASA, most of them with SVS and HUD experience, one with neither. He did just fine. They flew more than 100 test approaches where we collected objective performance data, and the pilots filled out questionnaires.”

“The second part was in a simulator. We rented Boeing’s m-cab [multipurpose engineering cab] 777 simulator, which had 787 displays, and had a dozen pilots fly more than 400 approaches. These were pilots from the FAA, EASA, UK CAA and a couple OEMs. They flew both ILS and LPV approaches and we deliberately introduced errors so we could watch the pilots’ responses.”

One of the main goals of SVLM is to provide lower-than-standard minimums for aircraft that are not equipped with a HUD. (Honeywell does not make its own HUD system.) “So we looked at how pilots made the transition from head-down to head-up at lower altitudes and in poor weather,” Feyereisen explained. “Can they quickly acquire the runway environment and make the transition to head-up, what was their landing performance, was the sink rate acceptable, did they land on the centerline, did they land long or short, how did the come over the threshold, were they in a position to land?

“After collecting and analyzing the data, we saw that we can almost provide Category III performance with the head-down display,” she continued. “We have equivalent performance compared with a HUD. When pilots come back inside the cockpit, they get the information they need much quicker with an SVLM display than with a traditional display. We found out we could meet the performance standard of a Cat II approach at a Cat I airport.”

Honeywell has delivered the data to the FAA and requested that the FAA and EASA create new approach charts that will support Cat II approach minimums when using SVLM on Cat I ILS and LPV approaches.

Said Feyereisen, “We’re still in the tail end of the proof-of-concept process, where the FAA now responds to our flight-test performance data and system safety analysis and gives a go-forward plan for certification. It’s a process. Personally, I believe SVLM brings new capability to the aircraft that we haven’t seen since the HUD. It’s a HUD heads down, but it has full color, a lot more pixels and it’s a lot easier to interpret, compared to the HUD’s monochromatic display.”