Despite all the fits and starts, NextGen in the U.S. will eventually affect business aircraft operators, although perhaps not on the schedule that the FAA currently espouses. It is not too soon to start considering the impact of NextGen on business aviation and how it will drive equipment requirements.

When the FAA air traffic control system was created, it had a simple mandate: keep aircraft apart. And that mandate stemmed from midairs that generated overwhelming public interest in crafting a way to keep aircraft from running into each other.

Fast forward a few years. Now we have the NextGen mandate, one that isn’t driven by accidents, which is a good thing because too many FAA regulations stem from tragedy. But because it isn’t driven by an overwhelming need to prevent immediate bloodshed, the Next Generation Air Transportation System is a kitchen sink of desirable features, an all-encompassing package of government and aircraft operator spending that promises to solve a lot of problems and that is going to cost a bunch of someones a lot of money.

Here is a seemingly innocuous statement from the latest version of the FAA’s NextGen Implementation Plan, recently updated in March: “The primary goals of NextGen are to enhance the safety and reliability of air transportation, to improve efficiency in the [National Airspace System] and to reduce aviation’s impact on our environment.”

Certainly these are well-intentioned goals, and they reflect the fact that the FAA’s mission has morphed into something more substantial than it was when the agency was founded in 1958. The NextGen plan is part of an effort to wrap ATC modernization into the FAA’s vision “to reach the next level of safety, efficiency environmental responsibility and global leadership.” When NextGen is fully implemented in U.S. airspace it will lead to great improvements in efficiency and consequent reductions in aviation-related emissions.

The global leadership part is debatable, because many air navigation service providers (ANSPs) around the world are in much more advanced stages of ATC modernization. In the U.S., NextGen funding remains hung up in FAA reauthorization legislation, which has been extended 19 times and remains bogged by legislators’ incessant penchant for adding burdensome special-interest riders onto the legislation. Many ANSPs in other regions are funded through user fees, which might explain why they are able to adopt new technology more quickly, but that’s an entirely different issue.

For operators, NextGen will affect three key areas: communications, navigation and surveillance, according to Andy McDowell, Jeppesen director of airspace and airports. “The goal of NextGen is higher capacity and efficiency within the system,” he explained. “The system consists of operations in airspace as well as on the ground. On surveillance, we’re looking at the transition to ADS-B. Communication is the move from voice-based to datalink. And navigation is the route structure based solely on RNAV and RNP. We’re going to have to have all three in place, the technology as well as the ATC operational plan that makes use of those technologies.” Surveillance is currently the sole FAA mandate, the Jan. 1, 2020 deadline to install avionics capable of broadcasting precise position information, known as automatic dependent surveillance-broadcast out (ADS-B out). While this is not yet an FAA mandate, some regions have imposed requirements for controller-pilot datalink communications (CPDLC) and future air navigation system (Fans 1/A) capabilities. CPDLC and Fans 1/A are datalink communications systems that allow pilots to communicate with controllers via electronic messages instead of voice. Over the ocean, datalink messages are routed via satcom.

Ground to Air

At its core, NextGen involves the transition from a ground-based to an aircraft-based navigation system, explained Steve Fulton, technical fellow at GE’s Naverus business. Fulton, who helped develop RNP procedures while flying for Alaska Airlines, cofounded Naverus, which was later sold to GE. “It’s a higher performance capability,” he said. “We’re no longer constrained to fly paths directly to or from ground navaids; we can create any path we need as the situation desires. There’s a tremendous amount of flexibility in the lateral and vertical paths.”

To make NextGen work, it’s necessary to employ something called performance-based navigation. PBN adds the time element to the three-dimensional path flown by an airplane to create a “4-D” solution, a defined trajectory that can be anything from an approach to an arrival to a full flight from taxi at the departure airport to parking at the destination.

The current system using radar and controllers vectoring aircraft is inefficient, because the time element isn’t precisely planned. Aircraft coming off an arrival procedure are vectored to an ILS first-come, first-served, and each aircraft carves a new path each time. PBN defines the trajectory that the airplane will fly, which includes when and where it will cross particular points in space. With the trajectory defined, Fulton explained, airplanes can arrive from divergent paths and fly to a merge point where they are synchronized into the arrival flow. Because they are using precise RNP navigation and ADS-B to broadcast accurate position, separation can be maintained at a tighter level than with ordinary radar surveillance. This allows for more aircraft to be handled, although airport capacity constraints still limit overall traffic levels. However, NextGen includes airport features such as real-time tracking and display of all aircraft and vehicles, which may help prevent incidents such as the one on April 11 in which an Airbus A380’s wingtip sideswiped the tail of a CRJ700 at JFK Airport.

Surveillance

ADS-B is here, now. A network of ground stations already provides coverage across much of the U.S., including the West and East Coasts, most of the Midwest, the Gulf Coast and a huge chunk of Alaska. Within these areas, properly equipped aircraft can already use some ADS-B services.

Picture ADS-B as an aircraft surveillance operating system, just as Microsoft’s Windows or Apple’s OS X are computer operating systems. With an operating system in place, a computer becomes a platform on which programmers can build useful tools for computer users, such as word processing, spreadsheets, engineering design and so on. Smart companies are already designing tools that play in the ADS-B space and that will provide a benefit to users (aircraft operators and the ANSPs/controllers). These tools are what make NextGen possible, and there is still a lot of experimentation and argumentation under way to select the best tools to run on the ADS-B platform.

It will probably take decades, in fact, to sort this all out. But as the FAA points out in the NextGen Plan, “One of the most difficult challenges is inserting all the NextGen advances, from the simplest to the most complex, into an aviation system that [must continue] to function 24 hours a day, 365 days a year. We cannot shut down the system while we upgrade it. When NextGen capabilities go operational, we will work incrementally. No one will throw a switch that turns on NextGen. Capabilities will come on line gradually. And we take a cautious approach to the infrastructure that enables NextGen advances.”

ADS-B out-equipped aircraft broadcast their identity, position, altitude, speed and other information to ground stations, which in turn send that information to air traffic controllers and to other aircraft. In essence, ADS-B can replace radar and is especially useful in areas where radar coverage is not cost-effective or possible. ADS-B allows for tighter separation between aircraft because information is updated more than once every second, unlike radar, which takes about 12 seconds to complete a sweep and provide an update. During those 12 seconds, a jet can change position by more than half a mile.

To use that information, other aircraft will need ADS-B in equipment, which the FAA has not yet mandated. According to the FAA, “The most basic types of [ADS-B in] enablers provide enhanced situational awareness, improving the ability of the flight crew to identify where aircraft are around them and the direction they are headed.” This information will be displayed on a cockpit display of traffic information (CDTI), which could be integrated with a Tcas display, the FAA noted. Some aircraft, in addition to upgrading to a transponder capable of ADS-B out transmission, may need a GPS sensor upgrade to the latest accuracy standards. After all, no one wants an aircraft broadcasting a position that isn’t highly accurate.

In the U.S., there are two ADS-B frequencies, 1090ES (extended squitter, the same frequency used by mode-S transponders) and 978 UAT (universal access transceiver). Aircraft that fly above 18,000 feet will broadcast their position using 1090ES, while those below can use either 978 UAT or 1090ES. Currently, ADS-B in-equipped aircraft using 978 UAT can receive traffic information and datalink weather and airspace information, for free. Aircraft equipped with 1090ES systems will be able to see traffic on CDTI displays, but the 1090ES doesn’t have the bandwidth to include datalink weather. However, avionics providers are including datalink weather capability in their systems using commercial service providers, but this isn’t free.

For low-altitude operations, it will soon (third quarter 2011) be possible to buy a TSO’d 978 UAT ADS-B transceiver for $4,995 from FreeFlight Systems, providing not only ADS-B out compliance but also access to free weather and ADS-B in traffic information. A company called Radenna makes a $950 UAT ADS-B receiver for the Apple iPad, which works either with Radenna’s SkyRadar or WingX’s moving-map software. For business aircraft, transponders, avionics systems and major upgrade packages include ADS-B out capability, but ADS-B in equipment is not yet ubiquitous.

What Next, FAA?

The big question: when will the FAA begin using all the capability the surveillance part of the NextGen equation offers?

The ADS-B network is scheduled to be complete in both the U.S. and Europe in 2013. The plan is to make some of the more advanced and useful ADS-B tools available starting around then, including in-trail procedures and automation over ocean routes. This means that properly equipped aircraft would be able to climb and descend to more optimal altitudes, in areas where aircraft currently can’t change altitude because of the huge separation standards needed for aircraft that can’t provide information about their precise position.

ACSS, a joint-venture company owned by L-3 and Thales, is doing some interesting work on these tools, and other major avionics manufacturers such as Honeywell, Rockwell Collins and Universal Avionics are developing or have made available some ADS-B capability.