For operators, breaking the “sight barrier” appears to be win-win: less onboard equipment and maintenance, fewer training hours for pilots, more abbreviated and intuitive approaches, and nearly all-weather access to airports. For air navigation service providers, it promises to equate a lessening of airport infrastructure and runway lighting required, and all the associated maintenance.
For its part, the FAA has opened the door for the sea change to occur through certain regulatory hooks. Order 8400.13D, published in 2009, allows for “special authorization” Category 1 approaches down to 150-ft. decision height and 1,400-ft. runway visual range visibility for runways without touchdown zone and centerline lighting, infrastructure otherwise needed for instrument approach system (ILS) minimums below 200 ft. “The higher-performance capabilities of new and improved avionics have mitigated some of the performance requirements of the ground-based navigation equipment,” says the FAA. In order to prove out the higher-performance capabilities, companies can elect to include with their certification efforts a proof-of-concept demonstration with the FAA, an approach Honeywell is taking to gain the agency's input on the operational suitability and airworthiness of their design before completing development.
While several avionics companies, business jet airframers and even one airline are known to be seriously considering a proof-of-concept or other certification efforts for the synthetic aid, only Honeywell and Rockwell Collins to date are openly discussing their plans to gain lower landing minimums “credit” for synthetic vision tools. Both companies view lower landing minimums for synthetic vision as stepping-stones to a “fused” or “combined” vision system that will blend validated synthetic vision, passive forward-looking infrared sensors and active radar-based sensors to allow a pilot to fly an aircraft all the way to the ground and to the gate for the most part with the primary flight display or head-up display, in Rockwell Collins's case.
Creating navigation systems that simplify the gate-to-gate operation of an aircraft by eliminating the impacts of weather is a key step in the technology roadmap to “equivalent visual operations,” a next generation air transportation system (NextGen) goal. The idea is this: If pilots have the guidance and navigation tools onboard to always fly as if the weather is clear and the visibility unlimited, then instrument procedures can be simplified and airports are likely to operate with fewer delays even as traffic grows, the exception being for severe weather.
Today, there is a graduated scale (Cat. 1-3) of required onboard and ground-based infrastructure for landing in progressively lower cloud height and visibility minimums, with the costs, training and maintenance increasing as visibility and cloud height decrease. Cat. 1 approaches, with a 200-ft. minimum altitude and 1,800-2,400 ft. of “runway visual range” visibility, are the most numerous ground-based approaches in the U.S., with 1,283 approaches at 1,200 airports.
The “holy grail” for NextGen is to get lower landing credit for the fast-growing number of GPS-based approaches called lateral precision with vertical guidance (LPV) that today allow for no lower than 200-ft. minimums. There are already 3,098 LPV approaches at 1,553 airports in the U.S.
“There is growing accessibility into airports without the economic benefit [of lower minimums],” says Sandy Wyatt, Honeywell's project pilot for SVLM and the pilot-in-command of my demonstration flight. “SVLM will unlock that capability in a way that the average pilot can easily fly.”
Rockwell Collins is initially focused on unlocking synthetic vision capabilities on Cat. 1 instrument approaches by leveraging its certified Pro Line Fusion synthetic vision for the head-up display, a system that first went into service on the Bombardier Global 5000 and 6000 in March 2012.
Matt Carrico, senior engineering manager of advanced concepts at Rockwell Collins, says testing of a prototype system on the company's Challenger 601 is already complete (for a customer he cannot identify) and certification activities with the FAA are underway.