Avionics designers are already testing avionics solutions that enable new air traffic management capabilities that are part of the Federal Aviation Administration’s (FAA’s) Next Generation Air Transportation System (NextGen) and Europe’s Single European Sky ATM Research (SESAR) initiatives.
BY John McHale
Air traffic management (ATM) in air traffic cockpits will have a new look by the end of this decade as airspace systems move from radar-based air traffic control (ATC) to satellite-based ATM technology, which will give air traffic controllers and aircraft pilots increasingly precise positioning in relation to other aircraft, thereby improving efficiency and safety in the air and on the ground.
The key initiatives behind the move to satellite-based navigation are the Federal Aviation Administration (FAA) Next Generation Air Transportation System (NextGen) and Europe’s Single European Sky ATM Research (SESAR).
“NextGen, and for that matter SESAR, are evolving to include higher-performance capabilities to deal with more complex operations and airspace. The core premise behind NextGen and SESAR is that they support a performance-based evolution,” explains Rick Heinrich, director of strategic initiatives for avionics specialist Rockwell Collins in Cedar Rapids, Iowa.
Several pieces must come together for Europe’s SESAR and NextGen to work—equipage in the airplanes, rules and protocols, and regulatory cooperation between different countries, says Mike Madsen, president of space and defense for Honeywell Aerospace in Phoenix. The last part will be the most difficult, he adds.
|The Boeing 787 Dreamliner will be compliant with ADS-B technology under the FAA’s Next Generation Air Transportation System.|
SESAR and NextGen must have similar rules and standards just to help with pilot training, Madsen points out. The airlines are anxious about this, but in the end it should be implemented, he continues.
“To be clear, NextGen and SESAR are not specific equipment implementations,” Heinrich continues. “They are part of a system of systems that enables change. Required Navigation Performance or RNP airspace was the first step in that performance-based environment. ADS-B Out is the next enabler and we are already working on the first elements of ADS-B In, which will provide even more capabilities.
Many different programs are in progress under NextGen and SESAR, but the key technology program driving satellite-based navigation is Automatic Dependent Surveillance-Broadcast (ADS-B). Earlier this year, the FAA’s 2012 total budget request was $1.24 billion—$372 million higher than 2010 enacted levels, or more than a 40 percent increase. Proposed 2012 FAA funding for ADS-B technology is $285 million, up from $200 million in 2010.
The FAA mandates that all aircraft flying in classes A, B, and C airspace around airports and above 10,000 feet must be equipped for ADS-B by 2020.
ADS-B will enable an aircraft to determine its position with precision and then broadcast its position, along with speed, altitude, and heading to other aircraft and air traffic control at regular intervals, says Cyro Stone, the ADS-B/SafeRoute programs director at Aviation Communication & Surveillance Systems (ACSS) in Phoenix, a joint venture company of L-3 Communications & Thales. ADS-B has two parts— ADS-B In and ADS-B Out, he says.
Where pilots will see the most improvements in situational awareness is with ADS-B In, which refers to the reception by aircraft of ADS-B data. ADS-B In is in contrast with ADS-B Out, which is the broadcast by aircraft of ADS-B data. ADS-B In will enable flight crews to view the airspace around them in real time.
ADS-B data broadcasts on a radio frequency of 1090 MHz and is compatible with the transponders used for the Traffic Collision Avoidance System (TCAS), Stone says. For the general aviation community, the ADS-B data link is 978 MHz, often called the Universal Access Transceiver (UAT) link.
The FAA’s ruling requires that all aircraft be equipped with the 1090 transponder by 2020, and that the transponder meet performance standards under the FAA’s DO-260B safety certification standard.
Experts from ACSS have already certified avionics equipment for ADS-B Out, Stone says. “We have certified equipment, such as a TCAS processor and 1090 squitter transponder”—the Xs-950 Modes S Transponder, which transmits the 1090-MHz signal with extended squitter (ES) messaging.
ACSS is working with US Airways and the FAA to bring ADS-B Out and In to the US Air fleet of Airbus A330 aircraft, Stone says. The work with US Airways will address efficiencies of its A330 fleet that flies from Europe to Philadelphia to improve flying efficiencies over the North Atlantic and become more efficient when landing at Philadelphia, Stone says.
The company also is working with JetBlue to implement ADS-B on that airline’s Airbus A320 aircraft, Stone adds. The JetBlue application will use the XS-950 Mode S Transponder starting in 2012.
ADS-B and DO260B products are approaching production levels over the next year or so and will be made available, says Forrest Colliver, avionics integration lead at Mitre Corp. in McLean, Va. Virtually no ADS-B Out equipment has been installed yet in commercial aircraft, Colliver says.
Many narrow- and wide-body air transport aircraft have transponders and multimode navigation receivers, which should help them comply with the ADS-B Out rule through service bulletins or manufacturer exchange, Colliver says. The key issue with the new rule, he says, is how operators will ensure the quality of ADS-B position broadcasts. This refers to “positioning source,” which aircraft and air traffic controllers use for safe separation and situational awareness. Position source also may be part of collision avoidance systems in the future.
“As with 1090 ES ADS-B Out, none of the aircraft equipped for ADS-B In meet the requirements of DO-260B; however, it is expected that avionics and airframe manufacturers will address modifications to these existing system as they define required ADS-B Out certification,” Colliver notes.
|Required Navigation Performance (RNP) will enable fuel and time savings under NextGen and SESAR.|
NextGen ATM and ADS-B
“Avionics has been evolving for the past several years,” says Rockwell Collins’s Heinrich. “The Wide Area Augmentation System, or WAAS, enabled improved approach and landing capabilities, providing more access to airports in a variety of degraded conditions. “What has been done in the new aircraft is establishing an architecture that supports incremental change with less intrusion,” Heinrich says. “In many cases, new functionality is now a software upgrade to an existing processor or decision support tool. We are working to establish ways to minimize hardware and wiring changes when change is identified. A great example is our Pro Line Fusion avionics system.”
Today’s systems generally provide key information through the displays, Heinrich says. “This is how the pilot is informed of relevant information. This means that as systems evolve, displays need to evolve. As aircraft operate in high densities, new alerts are required.
“Let’s use TCAS as an example,” Heinrich continues. “When we changed the vertical separation using Required Vertical Separation Minimums (RVSMs), we found that we had more TCAS alerts. While there was no compromise in safety, the design thresholds did not reflect the new operational limits. We can expect more of the same as we increase the precision of the system using RNP and ADS-B. Procedures for 1-mile separation are already in development. Terminal area operations will be even more ‘dense’ and older alerts will need to be improved.”
Rockwell Collins has several aircraft operating in RNAV and RNP airspace, which is part of NextGen and SESAR, Heinrich says. “We have been part of the initial ADS-B Out applications for global operations. And in Europe, we are a pioneer in the data communications program known as the Link 2000+ program.”
The SafeRoute class 3 EFB NEXIS Flight-Intelligence System from Astronautics Corp. of America in Milwaukee, Wis., will fly on Airbus A320s and host applications, such as traffic information, in-trail procedures, enhanced en-route situational awareness, and enhanced airport surface situational awareness. Safe- Route enables ADS-B-equipped aircraft to use fuel efficiently while flying over oceans, Stone says. Operators also can use SafeRoute-M&S (merging and spacing) to help aircraft line up for arrival and landing.
|Business jets, such as the Bombardier Global Express aircraft, will also have to meet ADS-B Out requirements by 2020.|
Retrofitting older aircraft for NextGen
One of the biggest NextGen challenges avionics integrators face is retrofitting relatively old aircraft by integrating new technology with obsolescent systems, and re-certifying software and hardware can create mountains of paperwork.
“It is one of the challenges, but I think it is important to realize that even the Airbus A350 and the Boeing 787 are already retrofit aircraft,” Heinrich says. “The system is evolving and the performance requirements are maturing. All of this will bring change, but the real issue is how the airspace will mature. A highly capable super aircraft would not benefit if it were the only highly capable aircraft. There needs to be a level of critical mass for an operation to evolve to a high-performance level. Even new aircraft with new capabilities are not enough to change the airspace by themselves.”
It always is easier to start with a clean slate on a new aircraft and be more efficient around system checks and “creating your own standard type certificates,” Stone says.
“There are more legacy aircraft than new aircraft,” Heinrich continues. “Studies illustrate that for some operations, 40 percent of all the aircraft need to have advanced capabilities for the procedures to work. It is very difficult to change arrival or departure operations one aircraft at a time. That is why there is so much work being done on stimulating change—making benefits available to those that equip as early as possible. You may have heard of the FAA’s Best Equipped—Best Served concept. That concept is intended to offer early benefits to those that step out early and equip.”
Best equipped, best served essentially gives priority to those aircraft that have the technology to approach and land in a more efficient manner, Stone says. Some in the industry roughly equates it to an HOV lane or FastLane toll booths.
Backing up satellite navigation with inertial measurement systems
Even though satellite navigation represents the future of air traffic management, inertial navigation system (INS) technology will not go away, says Mike Madsen, president of space and defense for Honeywell Aerospace in Phoenix. There is great need for inertial technology to step up when GPS satellite navigation signals are not available. INS technology refers to spinning-mass, fiber-optic, or ring-laser gyros that keep track of aircraft based on time, aircraft heading, and aircraft movements.
There is especially high demand for INS technology in aftermarket systems, Madsen adds. Over the last 20 years, precision INS capability has continued to decrease in size and weight, and increase in performance, particularly with the advent of ring laser gyros and fiber-optic gyros, Madsen says. Current efforts for future development will continue this trend, he adds.
Increasingly accurate inertial systems make overall flight management systems more efficient, Madsen says. It enables operators to make better route decisions earlier and saves time and fuel, he adds.
They also enable precise landing when an aircraft is in the middle of a GPS-absent or GPS-denied environment because inertial systems ultimately rely on the presence of gravity—and “you can’t jam gravity,” Madsen notes.
Military compliance with NextGen
While military aircraft are not required to comply with the Federal Aviation Administration’s NextGen initiative, FAA officials are working closely with the Department of Defense and avionics integrators to ensure capability.
“NextGen and SESAR are airspace evolutions,” says Rick Heinrich, director of strategic initiatives for Rockwell Collins in Cedar Rapids, Iowa. “The transition to a performance-based set of operations was specifically intended to avoid equipment-specific solutions but was focused on a capability. Military aircraft that operate in the commercial airspace face the same challenges that other retrofit aircraft face. Remember that military aircraft were the first to be GPS-equipped so they actually led many of their commercial equivalents in terms of space-based change.
“What the military faces is more of a planning horizon,” Heinrich continues. “They need to plan and create funding streams for their change. This is somewhat different than commercial users that can equip in a more discretionary way. This is why the retrofit cycles can take 10 years. Five of those years may be in the program planning and funding cycle, while the retrofit may actually align with an airline five-year change cycle.”
The way the military operates aircraft in terms of air traffic control, they are independent and do not operate on a national or regional grid, so therefore they are not a driver of NextGen technology, says Mike Madsen, president of space and defense for Honeywell Aerospace in Phoenix. On a day-to-day basis, F-18s, for example, will not be required to be NextGen-compatible, he adds.
Military systems are definitely applicable to NextGen as they already use GPS and the military is an operational leader when it comes to defining requirements, so adapting to NextGen where needed would not be a problem, Madsen says. At Honeywell, many avionics devices and systems are designed for dual use—commercial and military applications—which not only enables shared capabilities and standards, but also helps to drive down development and qualification costs, he says.