Do you see what I see?
Flight deck vision systems enable operations in low-visibility environments and improve reliability.
By David Ison
Professor, Graduate School Northcentral University
Just like many types of advanced avionics, synthetic and enhanced vision systems (SVS and EVS, respectively) are products of military applications which have been around for more than 60 years.
The most prominent case of vision systems (VS) integration occurred on the Grumman A-6 Intruder, when operational necessity demanded the ability to find and track targets in conditions not conducive to unaided visual detection. The A-6 Intruder was then equipped with infrared cameras to allow for Low Light Level Television (LLLT) displays of supply line traffic in the jungles of southeast Asia.
Since the Vietnam War era, VS have been tweaked and upgraded to improve reliability, image quality and processing capabilities, and reduced cost of components. All of these developments eventually made the technologies accessible to non-military aviation users. In particular, business aviation has been an early adopter of VS, along with some other general aviation segments.
Decoding jargon
As the VS space grows and evolves, so the various abbreviations and nomenclatures that represent them also change. SVS provides computer-generated imagery that mimics the topography ahead of the aircraft. Many SVS add other components, such as obstructions and airport features, like runways.
The levels of detail vary from one manufacturer to another, but they typically have intuitive color markings to represent terrain features and elevations.
Another feature often available through SVS is a highway-in-the-sky. This is represented as a magenta line to follow, or even boxes through which an aircraft is to be flown – something akin to a 3D flight director. SVS can be a pretty “quick fix,” as it is an avionics display upgrade or a software version change.
EVS, meanwhile, uses external cameras – generally infrared types – to give pilots real-time imagery of what’s outside and ahead of the aircraft. As you can imagine, EVS provides a more detailed picture of the environment, including necessary details such as trees, wildlife, vehicles, and other aircraft. EVS is less accessible due to the cost of sensors and the fact that it usually requires new cockpit displays installed.
It didn’t take long for civilian avionics companies to combine SVS and EVS, thus the term combined vision systems (CVS) was born. Two primary versions exist. One is where the EVS display is shown in the center of and blended into surrounding SVS imagery. The other is EVS imagery that is enhanced with SVS features displayed as an overlay of sorts. CVS provides the best of both worlds among VS, but still requires costly installations of sensors and displays.
Early on, SVS, EVS, and CVS were limited to being available on cockpit displays. While the addition of VS was certainly game-changing in terms of improved safety and situational awareness (SA), utility during highly dynamic phases of flight – namely takeoff and landing – was limited to the need to look down constantly. This also made transitioning from VS to visual conditions outside the window challenging. It wasn’t until VS was made available on head-up displays (HUDs) that they reached their maximum utility.
These augmented installations are technically referred to as enhanced flight vision systems (EFVS). And it was also not until 2016, when EFVS had been run through the gamut, that FAA granted special privileges to operators with such installations as being able to descend to 100 ft AGL or to fly all the way to landing via the use of the system. For reference (FAA), see 14 CFR Part 91.176 (FAA); or (EASA) Easy Access Rules for All-Weather Operations (CS-AWO), Subpart A – Enabling Equipment.
There are also synthetic vision guidance systems (SVGS), which is most easily described as an SV-based primary flight display (PFD) with flightpath vector (FPV) and other “pilot-in-the-loop” HUD-based symbology data. SVGS, in theory, provides a cheaper alternative to EFVS, and is certified to allow for slightly lower descent abilities (down to 150 ft AGL).
Let’s take a look at avionics that have surfaced to take advantage of these technologies.
Avidyne
Avidyne had every intention to enter the CVS market, including demonstrations of beta versions of its proposed system at AirVenture back in 2008. Because of what was most likely a market analysis of costs and user attributes, the company decided to drop aspirations of CVS and focused instead on SVS. The result is something far from inferior to other available systems.
One of the latest releases is their Vantage Flight Display System, which offers dual 12-in PFD/multifunction display (MFD) upgrade(s) for general aviation, and features SVS and a hybrid touch user interface. This system is affordable.
Cirrus owners can snag it, available at time of publication for $25,000. And there is little compromise made for the low cost – the SVS display is an SA hero, providing realistic terrain imagery color coded to display the threat level to the aircraft. Additional features include magenta line navigation and a HUD-like flight information display.
Collins
Collins has long been a leader in the VS environment. They have been quick to embrace SVS, EVS, and CVS. The company’s broad experience in avionics, including HUD guidance system (HGS) technologies, has made for a perfect union of components to leverage VS and HUD in concert.
One of Collins’ most recent additions to VS options is the EVS-3600, which blends short-wave infrared, long-wave infrared, and visible high-resolution cameras into a tri-band system. This combination enables passive terrain detection and removes the hindrance of low ambient light levels in terrain or threat identification. When coupled with HGS, EVS-3600 qualifies as EFVS, and is capable of either approaches to 100 ft AGL or to touchdown, depending on user certification.
Taking a step further, users can opt for CVS for optimal performance. Collins’ CVS boasts thermal imagery of terrain during night operations, high-resolution synthetic vision virtual terrain (unaffected by weather), and the fastest detection of runway and approach lighting systems for continued landings. Collins also modified its EVS to deal with detectability issues of runway LEDs, which emit less heat than older incandescent versions.
Gulfstream G280 flight deck with Collins Pro Line Fusion suite featuring head-up guidance system.
Garmin
Garmin offers VS solutions for aircraft of all types and sizes. Its G5000 suite, for example, has landscape-oriented 14-in displays with intuitive touchscreen controllers.
Optional equipment includes synthetic vision technology, which shows a 3-D virtual reality landscape on the flight display, with terrain, obstacles, traffic, and runway environment in graphical perspective.
The GHD 2100 HUD works with the Garmin’s integrated flight deck systems, giving pilots an out-the-window view of their PFD.
Citation Latitude flight deck centered around Garmin G5000 suite.
Honeywell
Honeywell has leaned into SVS more so than EVS, but the results are impressive. Honeywell’s SmartView avionics package allows for SmartView Lower Minimums (SVLM), which translates into Cat II capabilities. SmartView provides a highly detailed computer-generated and enhanced display of the outside environment, along with superimposed HUD-like flight instrument and navigation displays.
Awareness tools are abound in SmartView, including acceleration cuing so pilots can lock in their desired energy state, simulated displays of the runway, and even precision approach path indicator (PAPI). Another nice feature is that the system is certified for use on various commonly used business aircraft, such as Dassault Falcon, Gulfstream, and Pilatus models.
The next chapter will likely follow in the footsteps of the 360 Display System – a helmet-mounted augmented reality display experience for civilian pilots. Features include a high-resolution 360-degree view that seamlessly matches the view outside the cockpit. It also provides traffic call-outs and flight instrumentation in the pilot’s field of view, which makes the Honeywell 360 Display ideal for flying at night, in bad weather or in congested airspace.
Falcon 8X EASy III flight deck powered by Honeywell Primus Epic equipped with Dassault’s dual HUD FalconEye system.
Universal
Not to be left out of the VS marketplace, Universal has created a complete EFVS solution that they call ClearVision. The system uses 4th-generation high-resolution, uncooled multi spectral EVS, which can easily detect runway LEDs and taxiway lights that have presented observance problems in older VS. Universal’s ClearVision boasts a 3D perspective view of topography, video mixed with thermal and camera imaging, constant daytime view of flightpath, and intuitive SA cues, greatly enhancing the safety of flight – particularly during the approach phase.
The availability of the system’s resources can be a game-changer for poor weather and nighttime operations, especially in unfamiliar locales and places with threatening terrain nearby.
ClearVision can provide 2 display options – via HUD or SkyLens. The system is certified to allow for no-natural vision approaches to landing in visibility as low as 1000 ft, and has recently been authorized for use in Boeing 737NG models, which is good news for BBJ operators.
Universal Avionics ClearVision captures EVS imagery which can be projected through the PFD, HUDs, or head-mounted units.
Conclusion
Although it took a little longer than perhaps it should have, the authorization of EFVS use to lower minima or even landing is a welcome addition for all aviation operators. The beauty of the variety among VS systems allows users to pick the level of capability in response to operational needs, as well as the limitations of the pocketbook.
The VS outlined here can potentially enhance operational reliability, especially in areas where poor weather prevails. The SA augmentation provided by VS reduces controlled flight into terrain (CFIT) risks dramatically – a critical improvement to safety as CFIT continues to rank highly among the causes of fatal accidents across the globe.
Since business aircraft can operate to just about anywhere, oftentimes in locations with no ATC radar coverage, limited approach options, and less-than-desirable equipment and services, the addition of VS capabilities can enhance completion rates and efficiency.
For those who need to get their passengers or cargo where they are needed and when they are expected, VS can help make that reality come true with reliability.
David Ison, PhD, has 35 years of experience flying aircraft ranging from light singles to widebody jets. He is a professor in the graduate school at Northcentral University. His book Navigating Weather was recently released by ASA Publications.