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Honeywell is upgrading the Primus Epic cockpit on the Leonardo AW139 with new features, including a track-based synthetic vision system (SVS) that can be used all the way down to the hover.
SVS is part of the Epic 2.0 Phase 8 avionics package that Honeywell launched at HAI Heli-Expo 2020. The company has already received technical standard order approval from the European Union Aviation Safety Agency (EASA) for the package, which will be added to the AW139’s type certificate for both new production and retrofit installations. Leonardo expects to obtain EASA certification for Phase 8 avionics by the end of April, with retrofit availability targeted for the second quarter of 2020.
The upgrade builds on Honeywell’s extensive history with SVS in the business jet market, where the company was the first to introduce this virtual representation of the outside world. “Over the past 10 years, since we led the industry with the introduction of SVS, we’ve continued to improve symbology — adding intuitive lead-in to runway presentations, better landing area highlighting, the best presentation of obstacles, and higher terrain resolution,” stated Jason Bialek, product line director for Epic 2.0 and 2.0+ integrated avionics systems.
Those enhancements have even included improvements in how water boundaries are presented, with special algorithms used to minimize discrepancies between the SVS and the real world’s constantly changing shorelines. At airports with multiple parallel runways, such as Los Angeles International, Honeywell provides “breadcrumbs” that guide the approach to the centerline on the selected runway. Along with other features, this helps ensure that pilots don’t mistakenly land on the wrong runway.
Of course, helicopters often are flying approaches to landing sites other than runways. So, when the time came to add SVS to the AW139, Honeywell knew it would have to optimize the system for rotary-wing operations. While some helicopters already have SVS, heading-based systems can’t be used in instrument conditions all the way down to the hover for a variety of reasons, Bialek explained.
“When you have high crab angles, the heading-based SVS is essentially presenting where your nose is pointed instead of displaying where you are actually going,” he said. That could be problematic in any number of situations, but particularly in rescue or other low-level operations over challenging terrain.
In the Phase 8 system, Bialek continued, “as you start to crab the helicopter, where you’re headed and your flight path vector will remain in view, on your primary flight display, unless certain speed or heading parameters are met and it is better to switch to a heading-based SVS. For very dynamic maneuvering — not typical during instrument, confined, or steep approaches — the Honeywell SVS will present a heading-based view.”
He added, “We worked for a very long time with Leonardo to perfect the transitions between heading-based and track-based presentations, ensuring it is comfortable and intuitive for average pilots. The system clearly annunciates when it is switching between the two presentations and presents the best [option], track- or heading-based, depending on the state of the helicopter.”
Moreover, the primary flight display adjusts to provide a clear view of the flight path even during a steep approach. “The HSI [horizontal situation indicator] will actually move slightly toward the bottom [of the display] to be out of the way so you’ve got an unobstructed view of your landing site on the SVS, even during steep approaches, which in helicopters can be as much as a nine-degree descent angle depending on the approach,” Bialek noted.
Honeywell’s SVS provides pilots with color-coded warnings on the SVS terrain surface that correlate with helicopter terrain awareness and warning system annunciations, as well as flight path vector guidance that makes it easier to avoid controlled flight into terrain events. The company has also upgraded the maps in the Phase 8 flight deck to a cleaner, sharper presentation, with more available symbols and terrain display, while adding a new cursor control device (CCD), which allows pilots to quickly select and program a string of waypoints.