The dawn of equivalent visual operations is leading to a new generation of onboard situational awareness and safety tools for the ground portion of a flight.

Thought leaders in the new technologies include Honeywell and Rockwell Collins, whose primary flight display and head-up display surface guidance prototypes, respectively, could come to market as certified products or upgrades in 3-5 years.

Equivalent visual operations (EVO), an element of the FAA's Next Generation Air Transportation System, refers to using onboard synthetic and enhanced vision technologies to allow pilots to make visual precision landings when visibility and cloud bases approach 0 mi. and 0 ft., respectively.

Both Honeywell and Rockwell Collins are researching EVO systems as the industry continues to develop standards for the systems, with Honeywell favoring key information on the primary flight display (PFD) and Rockwell Collins opting for similar cues on the head-up display (HUD).

Either solution, however, will require a companion surface guidance system on the flight deck to make EVO economically practical at a large number of airports, where low-visibility taxiing would otherwise require the facility to have costly extra infrastructure and training as part of a surface-movement guidance and control system.

Along with enabling EVO, the workload-reducing surface guidance systems should be a boon to runway safety, which has been on the NTSB's list of most-wanted safety improvements since 1990. Of particular concern to the NTSB are runway incursions, excursions and selection errors.

Though an increasing number of aircraft have access to own-ship moving-map displays that show location on a 2-D map either on the multifunction display or electronic flight bag, the concept of pilots having to look away and down from the direction of flight to see and interpret the data, particularly at airports with complex and confusing layouts, leaves much room for improvement.

At Rockwell Collins, engineers and human-factors researchers are experimenting with a surface guidance system that features an egocentric 3-D synthetic vision HUD view that incorporates a sub-image of the 2-D airport map. Aviation Week viewed the latest developments during a briefing at the company's Cedar Rapids, Iowa, home base in February.

Matt Carrico, senior engineering manager of advanced concepts at Rockwell Collins, says the company formulated the surface guidance system for an earlier technology demonstration program, but at the time airport maps with required accuracy were not available. “It was ahead of its time,” he says. “We didn't have the data we needed to compose the accurate maps until recently.” He says Rockwell Collins uses “multiple database providers” for the maps.

One likely source is Boeing subsidiary, Jeppesen, which has high-definition maps of the surface area and buildings at more than 800 airports around the world. The company's vector-based Airport Mapping Database has a minimum accuracy of 16.4 ft. Jeppesen provides the airports database for Honeywell's surface guidance system, an extension of its SmartRunway option, which issues aural position reports and alerts, as well as some text notes, based on the aircraft's position during taxi.

The prototype system, sampled by Aviation Week during a visit this month to Honeywell's Deer Valley facility near Phoenix, features a 3-D synthetic-vision view of the airport environment on the PFD. Pilots will select the surface guidance system by toggling a switch, converting the PFD to a primary taxi display, says John Suddreth, a principal research and development scientist with Honeywell.

Key to Honeywell's solution is a tactical exocentric view that allows the pilot to have a bird's-eye view of the aircraft, shown as a model centered in an active compass rose, in the taxiway environment. In one version of the system, the pilot-entered taxi route is displayed mid-screen, with the route highlighted with a magenta line and ground speed shown. “Hot spot” locations identified by the FAA as having a heightened risk for incursions are marked with red and white segmented circles, and runway hold-short lines are emphasized by a drawing of a wall in front of the aircraft. In the prototype, other aircraft or vehicles equipped with automatic dependent surveillance-broadcast equipment are shown as tetrahedrons.

Suddreth says engineers and human-factors specialists developed the system by “taking everything away from the pilot,” then adding in only the information that “bought its way” back onto the flight deck. He says Honeywell has been showing operators the concept for more than a year and is working with industry groups to develop concepts of operation for the system.

Rockwell Collins's prototype system requires pilots to enter the taxi clearance into the avionics manually; it then shows up as a black route line along the appropriate runway or taxiway in the HUD 2-D map view. The 3-D portion of the HUD shows airport buildings as the centerline and edges of the taxiway as a line and diamonds, respectively, suspended above the route. Included as data fields are ground speed, target speed, distance to the next turn, direction of the next turn and distance to any “holds” in the taxi clearance.

Audio call-outs include an alert when the pilot strays off the entered route, distance to the next turn, direction of turn and distance to a hold.

Availability of Rockwell Collins's system is tightly coupled to the human factors of entering the taxi route, which can be long and complicated, depending on the airport, weather and time of day. Beyond 2018, the FAA plans to have infrastructure in place to send taxi routes via data-link messages from the control tower directly to the aircraft, but the schedule for that could slip given the ground infrastructure and procedures required. Until then, the most likely entry method will be manual, or possibly by voice.

“The timeframe for the taxi route capability will be sometime in the next three years or so, particularly if we can find a convenient way for crews to enter it,” says Carrico. “It may start as route out from parking. On landing, there's a high workload environment and you may not see heavy utilization until the control tower can data-link the route to you.”

He says the company continues to research voice-recognition software as a method of entering the taxi route from the gate to the runway, particularly since pilots today must repeat the cleared route over the radio before taxiing can begin. “It's not a bad application for voice recognition because of the constrained vocabulary,” says Carrico. “But it's really hard to [read it back] without the pauses or 'umms' or 'ahhs' that throw off the voice recognizer. There's some work to do to get it to work with natural language.”