Great strides have been made worldwide as air navigation service providers (ANSPs) leverage several technologies to increase air traffic management efficiency both in the air and at airports.
Indeed, India, Singapore, Hong Kong, Central America and the Caribbean are using Aireon’s space-based ADS-B air traffic surveillance system joining 12 other ANSPs in 37 countries.
Airports Authority of India (AAI) is using Aireon successfully across Mumbai, Chennai and Kolkata’s oceanic airspaces, providing an additional layer of surveillance for the world’s third largest airspace.
Airservices Australia is using data sharing to become the first ANSP to implement Airport Collaborative Decision Making (A-CDM) at multiple locations using data sharing to become the first ANSP to implement Airport Collaborative Decision Making (A-CDM) at multiple locations — Melbourne, Sydney, Perth and Brisbane — using a Saab Sensis system expected to save $52 million in fuel and emissions by 2030 by increasing airport efficiency.
In November, Aireon partnered with FAA to explore its use in validation and integration into air traffic control automation platforms, airspace safety analysis, accident investigation data analysis, airport surface applications, air traffic management support, remote situational awareness and commercial space.
The agency reported it continues to develop and deploy new systems or system enhancements to improve operations and fuel efficiency, including ADS-B, Data Communications, Time-Based Flow Management and Terminal Flight Data Manager technologies to expand coverage in the Gulf of Mexico and remote areas of Alaska. It is using ADS-B to reduce separation from five to three nautical miles en-route below 23,000 feet.
In addition to ADS-B, said Aireon, industry’s toolbox includes such technologies as digital voice, trajectory-based operations, virtual towers, autonomous monitoring, ACAS-Xu (providing both collision avoidance and detect and avoid capability for UAS), dynamic routing, continuous data exchange and AI.
North Atlantic Results Show Reduced Emissions
“In my judgement, the most important real contribution to increased ATM efficiency is space-based ADS-B,” Reason Foundation Director of Transportation Policy Bob Poole told ATR.
A year past FAA’s mandate for ADS-B Out, it is clear leveraging its data is a powerful tool for innovation.
In 2019, NAV Canada became the first ANSP to use satellite-based surveillance to track aircraft over the North Atlantic, previously a dead spot in radar-based surveillance, and has since partnered with UK’s NATS to cut emissions on Atlantic routes.
Covid-related reductions in air traffic allowed NAV Canada and NATS to experiment with using the Jetstream, which can soar between 100 and 200 knots, to improve efficiency. A test analyzing around 35,000 flights between December 1, 2020 and February 29, 2021, showed changes to current ATC practices increases efficiency between New York and London.
Authors of Reducing Transatlantic Flight Emissions by Fuel-Optimized Routing, said Low Earth Orbit (LEO) satellites, coupled with technology, enabled them to test fuel optimized routes.
“These new routes take greater advantage of the prevailing eastward winds when flying east and reduce the negative impact flying west,” they said. “The conveyor effect of winds saves a significant amount of air distance and thus fuel and emissions by adopting the Optimized for Winds (OFW) routes. Using ICAO’s carbon emissions calculator, we determined a return flight between London and New York generates 670 kg of CO2 per passenger for a potential saving of over 6.7 million kg of CO2 emissions across the winter period of each year alone.”
Based on the results, NATS announced in its blog it was disbanding the Organized Track Structure on days where ATC supervisors don’t believe it necessary.
ICAO’s Cost-Benefit Calculating Tool helps ANSPs analyze the costs and benefits of implementing CNS/ATM systems. The agency said a broad economic study indicated that, globally, benefits greatly exceeded the costs and called the replacement of the existing line-of-sight systems with satellite-based air navigation services, a quantum step forward.
Collins Aerospace Director of FAA & Government Programs Gene Hayman indicated the calculator, developed in the mid-2000s, is a good tool and relevant to making sure the right questions are asked. But, like any tool, it must evolve.
Transformational Change
“More flights received requested flight levels, speed and routes,” said NAV CANADA President and CEO Neil Wilson in a blog. “Since March 2019, longitudinal standards have been reduced from approximately 40 nautical miles to 14-17 nautical miles, and lateral separation reduced from 23 nautical miles to 15-19 nautical miles for equipped aircraft. The deployment of space-based ADS-B is the beginning of a global revolution that is already showing its promise by delivering enhanced safety, efficiency and environmental benefits. This is expected to reduce overall safety risks by approximately 76% in the North Atlantic. Based on a study conducted by NATS and the International Civil Aviation Organization (ICAO) CO2 emissions are estimated to be reduced by approximately two tons per oceanic flight.”
Time to Experiment
Hayman reported industry and government are looking for other ways to leverage reduced traffic to demonstrate technology.
“Now is the perfect time from a safety perspective,” he said. “The next 12-24 month is a great opportunity to start looking at new technology and concepts.”
He pointed to the industry/government Blue Skies Initiative (BSI), sponsored by Air Traffic Control Association (ATCA), which is looking at emerging technologies, commercial space and advanced air mobility.
“The question is how do we make these new capabilities happen and what science needs to happen to integrate these new technologies quicker,” he said. “It could have significant impact on space launch windows. Today a wide area of airspace is closed to accommodate the increasing number of launches, but with more data on how launches impact the system, it could provide better predictability and significantly shorten airspace closures.”
Another bright spot in ATM efficiency is the gradual increase in free-route airspace in Europe applied at upper altitudes where it has been negotiated between adjacent ANSPs, Poole added.
“That is definitely saving time, fuel, and CO2,” he said. “Some visionary ideas are being discussed in Europe, such as unified upper airspace regardless of national boundaries, and virtual en-route centers, but I don’t see any of this moving beyond the talk stage.”
Creating a Connected Aviation Ecosystem
Moving from an ATC-controlled information stream to delivering that information directly to pilots, controllers, airports and aircraft operators is perhaps one of the system’s greatest promises; one that could include collaborative decision making.
Honeywell Aerospace Senior R&D Manager, Don Kauffman explained one goal is to add capability to the flight deck to increase operations under instrument and marginal meteorological conditions to those of visual conditions to increase capacity. He pointed to the collection of flight deck applications that make use of ADS-B messages and Required Time of Arrival (RTA) capability available on all Honeywell Flight Management Systems (FMS) that are FANS-capable. It can deliver an aircraft in cruise to a waypoint with an accuracy of +30 seconds. Honeywell’s FMS for the Boeing 787 also extends RTA capability into all phases of flight.
“Ideally,” said Kauffman, in discussing the challenges of merging two arrival streams, “aircraft arrive at the merge point spaced exactly at the minimum, safe separation distance. Fundamentally, the goal is to keep aircraft spaced sufficiently such that interventions to breaches can be taken in time. RTA applications tracks performance to the RTA goal and continually makes minute adjustments to the aircraft speed.
Kauffman added Flight deck Interval Management (FIM) applications automatically calculate speed commands easing pilot workload by “capturing” the designated traffic, either speeding up or slowing down to achieve the desired spacing.
In addition to Honeywell’s systems, Flyht Aerospace Solutions offers its AFIRS SatCom solution for FANS and ATC/ATS Safety Service Voice.
“A leading U.S. Airbus operator demonstrated by using AFIRS, a return on investment could be achieved in approximately 15 weeks, using SATCOM voice/datalink to fly direct routing from the US to the Caribbean,” Vice President, Sales & Marketing Derek Taylor told ATR. “This reduced sector flight time, fuel burn, crew duty time and eliminated the need for overnighting and associated logistical costs. Flyht’s technology connects the aircraft to the ATM network while over remote areas, out of VHF range, and/or in oceanic airspace.”
Pro-Active ATM Management
“This will turn air traffic management from reactive to pro-active using historic and current data to look out days in advance to make better predictions about the airspace and better models for air traffic flow, all to create better decision support tools to help the system become more efficient,” said Hayman. “Automated data sharing gives everyone the same information so routes can be optimized for fuel and airspace. Fifteen years ago, the industry suggested making the aircraft another node on the network. The whole concept of the fully connected aviation ecosystem is now a reality because the operational technology is being integrated with information technology, and being transmitted digitally to transform air traffic management (ATM).”
L3Harris Director Business Develop Mission Networks Chris Collings agrees. “In today’s ATM environment, efficiencies are gained by combining technologies with updated procedures to modernize air traffic management,” he told ATR. “Technologies like GPS navigation, terrestrial and space-based ADS-B, Data Comm’s Controller Pilot Data Link Communication (CPDLC), improved weather information products for optimal routing, and System Wide Information Management (SWIM), all enable new ATM procedures that drive efficiency. As rollout and adoption of these technologies increase, as it has in recent years in the U.S., we are now beginning to see those efficiency benefits.”
FAA said its surface surveillance system provides controllers and operators with surface information at major airports via SWIM. For operators, the information supports more efficient ground/gate operations and better fleet management. The Surface Visualization Tool provides information about current surface operations, improving the ability to integrate departing aircraft more seamlessly into the airspace.
Collings said from L3Harris’ perspective, it is entirely possible the improved situational awareness provided by SWIM could enable airspace users to upload their information to share with ATC for collaborative decision making across the airspace and surface operations.
In the en-route environment, Collings explained, Data Comm’s Controller Pilot Data Link Communications (CPDLC) enables controllers to send revised routes that are not feasible using voice alone such as precision latitude/longitude and complex place-bearing distance instructions. These clearances enable controllers to send shorter and more precise re-routing for flights.
“Operators using Data Comm’s Departure Clearance capability have reduced gate delays and shortened taxi times from the efficient digital route clearance that pilots load into their flight computers,” he said. “Not only does data transmission reduce readback errors but pilots avoid lengthy voice channel wait times to get route revisions. This can really save time during busy weather delay events. Combining ADS-B information with Performance Based Navigation (PBN) capability of the aircraft, enables ATC to develop new procedures replacing separation to more efficiently route aircraft, dramatically increasing fuel savings. Terrestrial ADS-B also provides broader surveillance coverage than the radar-based surveillance ATC system it replaces, which opens new, less congested routes for operators.”
Industry Frustrations
Poole sees only modest improvements from CPDLC in the U.S. where it is used for expediting tower departure clearances with little or no impact en-route. Similarly, he reported slower progress in Europe.
“The mostly good news is that the first steps of phase two — equipping en-route centers with Data Comm capability — is operational at Indianapolis and Kansas City [and Washington Centers],” said Poole. The pandemic has caused deployment delays.
Poole is not alone in his criticism. Airlines for America (A4A) pointed to the Total Delay Impact Study — conducted by a consortium of universities and funded and updated by the FAA.
“U.S. flight delay costs to airlines and passengers have exceeded $20 billion every year since 2007 and that number has increased to $30 billion in the last few years,” the organization told Aerospace Tech Review. “NextGen promised between 5% and 12% fuel and emissions savings and is an unrealized promise. Even a 5% savings in 2018 would have eliminated nearly 10 million metric tons of CO2, equivalent to taking more than 2.1 million cars off the road for an entire year. PBN is an example of a foundational capability that enables an aircraft to navigate using precise performance standards on a desired flight path. However, its deployment has been delayed consistently and the intended goals — added safety, lower emissions, less total noise exposure, improved airport access during bad-weather and improved predictability benefits — have not been achieved.”
That may be so, but technology has existed since 2001 — independently validated by FAA, Embry-Riddle Aeronautical University, GE Aviation, Delta and Georgia Tech — proving that if airlines managed their aircraft in real time, from gate-to-gate, making adjustments in flight, they could have lowered emissions (CO2/NOX/noise) and reduced costs, while improving ATC efficiency, on-time performance and schedule reliability. The technology is ATHGroup’s GreenLandings solution, developed by former United Captain Michael Baiada and his partner Lonnie Bowlin. Airlines counter with “it can’t be done,” while advocates, like Aviation Consultant Robert Mann, say, instead of waiting for the long-promised benefits from NextGen, airlines could have solved congestion problems years ago with this low cost, self-help solution.
Ground Based Augmentation System (GBAS)
“The pioneers who envisioned NextGen as a transformation of U.S. air traffic control, assumed that aircraft would be guided to airports by RNP precision approaches linked to all-weather GPS-based landing system, replacing legacy instrument landing systems (ILSs),” said Poole, adding GPS-based landing systems are not included in NextGen leaving airlines and airports including United hubs Houston and Newark, to buy and install the systems themselves.
Poole cited several benefits to GBAS such as no signal interference and blind spots that plague ILS. GBAS also does not require a separate system on every runway end.
“Honeywell’s latest GBAS version can serve up to 48 runway ends from a single system,” he said. “It offers the standard 3-degree ILS glideslope, but also offers a 3.2-degree glideslope, reducing noise by keeping planes somewhat higher as they approach the runway. There’s no business case for ripping out current ILSs with many years of useful life remaining, but for airports with serious fog problems like San Francisco (SFO) and Seattle (SEA), GBAS offers considerable potential, especially once more-precise CAT II and Cat. 3 systems are certified, which in now close.”
Poole sees the same business-case for large European airports, noting the chicken-and-egg problem of aircraft equipage driving airport equipage has been overtaken by an upward trend in equipage.
“At the ICAO GBAS/SBAS workshop in Seoul, Boeing reported that more than 3,000 of its airliners are GBAS-equipped, with 72% of deliveries having GBAS,” Poole reported in Aviation Policy News. “GBAS was an option on the A320, A330, A350 and A380. The GBAS Alliance was created by GBAS producer Indra Navia and Airbus and its nearly two dozen members include airports, airlines and ANSPs. They are targeting key airports and ANSPs. Indra’s NORMARC GBAS completed flight tests at Hong Kong and the company says its home country, Norway, has used GPS-based landing systems at 17 airports for years. Germany’s DFS (which pioneered CAT I GPS at Frankfurt in 2012) is now actively planning for CAT II and Cat. 3 systems, with the first evaluations set for Bremen Airport. DFS expects that by 2030 only 20% of its ILSs will still be in operation, mainly as backups for GPS outages. ICAO has approved GBAS CAT II/3 standards.”
Poole noted Honeywell’s development of a CAT II modification to its CAT I GBAS ground equipment so planes equipped with its Smartpath CAT I avionics can fly CAT II approaches. As soon as FAA approves operating specifications for this, he said, American, Delta, and United airliners will be able to fly CAT II GBAS approaches at Houston and Newark.
Leveraging Big Data
Aireon sees ubiquitous data exchange as the basis of all future operational paradigms with AI fundamental to the ability to transition to a big data environment.
Collings agrees. The biggest role that big data provides today to ATM is the ability to measure improvements and identify areas of optimization. For example, by analyzing thousands of flight plans filed and comparing to actual routes flown, aircraft operators can avoid a lengthy route revision process before departure resulting in a more efficient process and reduced delays.
FAA also sees machine learning and artificial intelligence as key technologies for improving safety. It already incorporates AI and machine learning into weather forecasting improving both tactical and strategic weather strategies. The Offshore Precipitation Capability uses machine learning to improve traffic management around convective weather between Florida and the Bahamas and is being extended to other areas where there is no coverage.
“Big Data is definitely here to stay,” Hayman concluded. “Having a previously disconnected aviation eco-system and building out Internet of Things, I truly think that will give us seamless ATM because you are allowing all the information to flow to all the stakeholders in real time.”