Plans to transform the US air transport system are slowly taking shape - and the proposals involve not just technology, but radical changes to how users think

Danville regional airport in rural Virginia is an unlikely location to be the birthplace of the next-generation US air transport system. But some believe that demonstrations at this general aviation airfield in June sowed the seeds for the transformation of US air traffic management.

The Danville demonstration was the culmination of NASA’s Small Aircraft Transportation System (SATS) research project. Aimed at enabling the thousands of small airports across the USA to become part of the public transport system, SATS has also served to demonstrate key technologies for the proposed Next Generation Air Transportation System (NGATS).

The first effort to transform the airspace system since the US Federal Aviation Administration’s “Brown Book” plan of 1981, NGATS is an ambitious initiative to not only cope with an expected tripling of traffic by 2025, but also enable the airspace system to handle very light jets, unmanned air vehicles and even spaceplanes as easily as it manages scheduled airliners.

The scope of the NGATS plan has drawn scepticism from observers of the FAA’s struggles to modernise its air traffic management system. Charlie Keegan, director of the Joint Planning and Development Office (JPDO) overseeing the NGATS initiative, disagrees: “There is no question about the FAA’s deployment record over the last four to five years. It has done everything it said it would do.” But, he says: “What we have deployed is 1980s technology and 1980s thinking. The vision of 20 years ago did not go far enough. We can’t let demand go much beyond where it is today. If we don’t start now, it will be too late by 2025.”

The JPDO is drawing up a multi-agency plan for transformation of the US air transport system. An integrated national plan delivered to Congress in December last year laid out a vision for the NGATS, and in June the JPDO outlined its proposed 2025 “airport kerb to airport kerb” concept, built around several key strategies:

Network-enabled operations An internet-like network that is not fixed to the ground will make information from private, commercial and government sources accessible, securable and usable in real time, and provide common awareness of operations, events and crises. Aircraft will be nodes on the network.

Today, communications are largely ground-based, labour-intensive, two-party exchanges, and voice and data sharing is a key component of the next-generation system, says the JPDO. Automation will sort through the mounds of data to make it comprehensible for all users, from pilots and controllers, dispatchers and flow planners, to screeners and air marshals.

Performance-based services Instead of handling every aircraft from a new Boeing to an old Cessna in much the same way, the next-generation system will give higher-performing aircraft greater operating flexibility. Multiple levels of service will be aligned with specific performance thresholds, and service guarantees will let users pick the performance level that suits them. Service levels will be set by assessing safety, security and environmental risks posed by each performance level. A culture change will be needed to tie services such as airspace access to user performance, says the JDPO.

Layered, adaptive security The USA needs to migrate to a network-enabled security operation by 2010, says the JPDO, which proposes a system that creates adaptive security envelopes for people, cargo, airports and aircraft. These would tie threat evaluation and response to the risk level.

Weather assimilation into decision loops The future system will be built to deal with the uncertainty in weather, says the JPDO. More accurate forecasts and real-time observations, including from aircraft, will be combined into a single national database that is updated automatically to provide a common weather picture across US airspace. Automation that learns from past experience with weather uncertainties will then be used to present options for managing aircraft trajectories.

Broad-area precision navigation The next-generation system will achieve the long-held ambition of precision satellite-based navigation and landing independent of ground-based aids at any US “air portal”. The JPDO believes this will open thousands of small airports to very light jets and bring air service to more communities.

Dynamic trajectory-based operations Today, air traffic is worked in real time with each flight individually controlled, says the JPDO. Controllers are handling an average 1.2 flights, but the busiest are serving 10-14 because workload is tied to geographic location and not easily shared. The next-generation system will introduce dynamic airspace operations, in which users “contract” with the FAA for airspace access and services months in advance.

Using machine-based analysis of four-dimensional (4D) aircraft trajectories provided by users, resources will be matched to demand, but then adapted days in advance to account for forecast weather and airspace restrictions, and adjusted hourly during the day of operations. Trajectories will be managed from “virtual” facilities.

Equivalent visual operations Precision navigation, on-board sensors and the ability of the cockpit and controller to share the same picture of the situation will allow the “maintain separation” function to be delegated to the aircraft within the next-generation system. Most routine operations, such as a passing manoeuvre or parallel landing, can be managed by the pilot on board, or remote pilot in the case of a UAV, says the JPDO. Maintaining a capability equivalent to visual operations as visibility reduces will allow airports to sustain capacity as weather deteriorates.

Super-density operations Equivalent visual operations, as well as performance-based 4D trajectories, are key to enabling more runways at more airports to be used at near-full capacity. As a result, says the JPDO, today’s busiest runways will only need to cope with a modest increase in throughput. Equivalent visual operations will allow close parallel landings, while real-time wake vortex information will allow separation between aircraft taking off and landing to be reduced.

The changes needed for system-wide transformation are fundamental, the JPDO says, and involve not only technology, but organisational structure, policy and culture – including the need the change to roles and responsibilities of pilots and controllers.

A “first cut” roadmap for transition to the NGATS has been drawn up, and multi-agency integrated product teams in each of the areas are reviewing and refining the plans. The JPDO is to deliver a key progress report to the White House Office of Management and Budget by the end of September.

“Where research into the technology is mostly complete, and the major issues remaining are policy, cultural changes and organisational, we are ready to start the transition [to NGATS],” says Keegan. Automatic dependent surveillance – broadcast (ADS-B) is one. “National deployment of ADS-B is well aligned with the move to co-operative surveillance. We need to fund it,” he says.

Meanwhile, SATS seems to be going the way of other NASA research programmes. The government-industry team is being disbanded, and the torch passed to the JPDO. “SATS was the first step towards realisation of NGATS. The JPDO acknowledges that, says acting programme manager Guy Kemmerly.

While the Danville demonstration generated enthusiasm for the potential of air taxis to serve small communities, what happens next is unclear. “Anything we do needs to be co-ordinated with the JPDO,” says Kemmerly. “We need a single direction for the future.”


Source: Flight International