KAREN WALKER WASHINGTON DC US plans for a modernised air traffic control system have undergone a sharp change in direction, making them evolutionary rather than revolutionary and putting the emphasis on government-industry collaboration. Such a programme is more likely to win Congressional support and become a reality.

"Ask 10 controllers what they think free flight means and you are liable to get 12 different answers." That observation, by Karl Grundmann, at the US National Air Traffic Controllers' Association, is equally valid outside the air traffic control (ATC) community. But the definition of free flight, North American-style, is emerging more clearly as the USA progresses towards its goal of implementing the free flight phase 1 (FFP1) programme by 2002.

It is also clear that this programme, although less revolutionary than what the Federal Aviation Administration originally envisioned, is gaining the all-important approval it needs from Congress. FAA Administrator Jane Garvey struck the right note when she decided to gather the support of airlines and industry for common, achievable goals and encouraged everyone involved to speak up for those goals with a single voice to Congress. It was Garvey's belief that Congress would be much more willing to vote to fund a programme that already had the consensus of industry and the airlines. So far, she has been proved correct.

The other shift in direction that has taken place since Garvey made modernisation of the national airspace programme a true collaborative venture with industry is the emphasis on what free flight, as part of that effort, will achieve for the airlines. Back in the early 1990s, much of the emphasis was on the cost savings that free flight would deliver to the US carriers. The argument was that it would allow many more air traffic decisions to be transferred over to the individual aircraft, enabling pilots to select the most fuel-efficient routes. Cost savings remain an important objective of FFP1, but now there are other, equally important, goals.

The past two years have seen an escalation in ATC congestion in the USA. A spate of bad weather - and the USA has experienced many severe weather-related problems in that same period - frequently brings a whole region to a standstill. Gridlock is now a much-feared word in US airline boardrooms. According to a study by American Airlines, an extra 4min delay to each flight is all it will take to overload the system completely. Some believe the US ATC system is faced with potential gridlock not far into the next century. While free flight on its own cannot address the gridlock problem entirely, it can buy time and breathing space. Bob Frenzel, vice-president of operations and safety at the Air Transport Association (ATA) and a member of the Radio Technical Commission for Aeronautics Free Flight Select Committee, the industry-government body responsible for drawing up FFP1 parameters, sums up the reason why such breathing space will be precious: "There have been dire predictions of gridlock, and with the explosion in regional jets it's getting closer. We could get to gridlock sooner than 2004. We are starting to feel the capacity constraints now," he says.

Despite the differing opinions, there is wide agreement on the "end state" of free flight, defined by the RTCA Free Flight Select Committee as a "safe and efficient flight operating capability under instrument flight rules in which the operators have the freedom to select their path and speed in real time". The RTCA goes on to add that "any activity which removes restrictions is a move towards free flight". The first such move, FFP1, is purely ground-based and involves making existing, but not widely used, air traffic management capabilities quickly available to deliver early capacity benefits to the airlines. Later phases will focus on other aspects, including safety. For example, by providing additional information to the cockpit and increasing situational awareness, the programme will enable pilots to make better decisions about potential weather hazards, be less likely to be involved in a controlled flight into terrain accident, and also navigate airport taxiways more safely. These are just some of the safety benefits that the programme is seeking to offer.

Parts of FFP1 are already in place and are being well received. Frenzel believes that the success of the programme owes much to the collaborative nature of the new approach to free flight. "Free Flight Phase 1 is on track," he says. "We are already seeing the initial benefits." He cites 'collaborative decision-making' software tools which allow airlines and controllers to work together to adjust air traffic flows to overcome weather-caused airport capacity restrictions without resorting to ground delays. Although it is in the early stages of implementation, FFP1 has already helped reduce delays, he says.

Business case for free flight

Frenzel believes the new approach is making it easier for airlines to make a business case for the cost of equipping for free flight. "If we do it incrementally, there's a better chance of getting the investment-but it's still a challenge." The shift to a consensus approach has helped, he says. The different user groups are being brought into the decision-making process, removing obstacles to agreement, and Congress is proving more willing to listen to a single voice. "The consensus is holding in most respects," he says.

"We are starting to see a reversal of the typical approach. This was to come up with a technology which a company produces and sells to the FAA, and which the FAA then tries to sell to the users. Now decisions have become more user-driven. We come to the FAA and say: 'We are the customer, and this is what we need'. There has been a phase shift, towards user-driven and away from technology-driven. Technology is good, but the users have to get something from it," says Frenzel.

To build on this consensus, the Satellite Navigation Users Group - led by the ATA and the Aircraft Owners and Pilots Association - has been formed to bring users together to work with the FAA on the transition to the global positioning system (GPS) and its wide-area and local-area augmentation systems (WAAS and LAAS). The group's biggest challenge, Frenzel says, is to protect funding for WAAS, LAAS and satellite upgrades - all critical to the use of GPS as the eventual sole source of navigation information.

Free flight will certainly have an impact on delays, says Frenzel, by allowing airlines to operate in reduced visibility, in much the same way that they do in clear weather. For example, rather than stack aircraft in single file as they wait to land at a weather-constrained airport, controllers will be able to bring them in from different directions and sequence them in directly to land. The current airways structure means that a flight can be held on the ground because of bad weather en route, even though the departure and arrival airports are clear; free flight will allow pilots to choose a flight path that avoids the bad weather. "Free flight is a bubble of safety around the aircraft which gives the crew discretion in choosing routes which avoid altitudes, winds and other factors that reduce efficiency," says Frenzel.

In general, Frenzel believes there is much to be optimistic about and that enthusiasm from US carriers for FFP1 is growing. "Free flight is off to a good start," he says. "It's picking up pace as we see the benefits. And once some people are benefiting, everybody will want it."

An illustration of the user-driven approach being adopted for the free flight programme is the Cargo Airlines Association's (CAA) plan to use automatic dependent surveillance - broadcast (ADS-B) as an alternative to the traffic alert and collision avoidance system (TCAS) carried by passenger aircraft. Frenzel says the ADS-B operational evaluation now being conducted by the CAA and FAA is important as it will quantify the wider benefits of the system - a key free flight technology. This plan is controversial because it is in direct opposition to the National Transportation Safety Board's insistence that all cargo aircraft should be fitted with TCAS, but the CAA continues to argue that ADS-B is a better long-term solution.

Despite the controversy, the ATA is becoming more actively involved with the CAA because, Frenzel says, "we need to support the FAA as it moves forward with ADS-B." This technology will be the key element of an ATA-backed demonstration planned for next year, in which United Airlines will test closely spaced parallel approaches to San Francisco International Airport. By using ADS-B to help pilots maintain safe separation between aircraft on the approach, United hopes to be able to keep runway capacity close to its clear-weather maximum as visibility deteriorates. Delta Air Lines is also becoming interested in the same technology for its Atlanta hub.

FAA a full partner

Interestingly, the CAA launched the programme to deploy ADS-B as an alternative to TCAS on its own three years ago; now the FAA is a full partner. Shelley Myers, director of the FAA's office of communication, navigation and surveillance systems, says: "The FAA has needed to be a partner with industry. The CAA was a big stick to prod us forward." As they evaluate ADS-B in revenue service, CAA member airlines Airborne, FedEx and UPS are also demonstrating some of the operational enhancements identified by the RTCA for the next phase of free flight. Frenzel says the CAA's ADS-B operational evaluation "is a testament to true government/industry partnership. It forms the foundation for the future vision of free flight. It's demonstrating what's necessary for free flight to happen".

However, free flight is not free. The airlines have invested much in terms of commitment, but relatively little in terms of hard cash. That will change, however, as the programme moves forward to Free Flight Phase 2. The RTCA has just begun work on defining FFP2, for implementation between 2003 and 2005. Whereas FFP1 is purely ground-based, FFP2 will require substantial investment by the airlines to equip their aircraft and will, therefore, be something of an acid test for the airlines' acceptance of the free flight concept. Frenzel says the consensus approach used to define Phase 1 will be applied to Phase 2 and that the signs for agreement are positive. But he adds the caveat that, while all sectors of the industry are committed to the "end state" of free flight, "each step has to show benefit". There may still be more answers than questions out there as to the true purpose of free flight, but for now US industry and government are speaking with one voice. And that in itself is an achievement.

Source: Airline Business