ATM Modernization, Business & GA, Commercial

ADS-B Launch: Performance-Based Strategy

By Adrian Gerold | July 1, 2006
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In early June 2006 the FAA's senior-level Joint Resources Council (JRC) approved Administrator Marion Blakey's choice of automatic dependent surveillance-broadcast (ADS-B) technology for next-generation surveillance in the National Airspace System (NAS). JRC approved an initial two-year baseline program, requiring FAA to check back next year with additional cost data. After that data is approved, the full program will proceed. Indeed FAA is counting on ADS-B as a cornerstone of its Next Generation Air Transportation System (NGATS). The JRC's endorsement of ADS-B followed Blakey's dramatic announcement a month earlier, describing ADS-B as the "backbone" of NGATS and likening it to the agency's version of the moon shot.

Since Blakey's announcement in May, the program has become more sharply defined. Dates and schedules have been fleshed out, and the tempo is accelerating, with the key screening information request (SIR) to suppliers planned for November. The SIR requires prospective bidders to describe in detail, including cost estimates, what they intend to offer--in this case, the nationwide network of some 400 ADS-B ground-based transceivers (GBTs). This in turn will allow FAA officials to closely examine each response to ensure it meets all the program technical requirements and to request further information, when necessary. Once all of these questions are answered, FAA plans to issue a request for offers (RFO) to qualified bidders in March 2007. The agency has requested $80 million in its FY07 budget, in part to work on backup analysis, separation standards, hardware development and activities leading to a notice of proposed rule making (NPRM) in FY07 or FY08. This process could be very lengthy, however, involving public comment, alternative proposals, counter offers and much negotiation. The final NPRM could take up to four years, according to industry sources.

Privatizing Surveillance

Up to that point the process will follow standard FAA procurement practice. But the bidders' offers and FAA's responses are expected to break new contracting ground. Possibly triggered by industry's concept of a nationwide leased/turnkey ADS-B network, FAA has become increasingly attracted to what it calls a "performance-based" acquisition philosophy. It now seems very likely that this approach will be adopted for ADS-B. Here, under a fee arrangement, the successful bidder would design, build, install, operate and maintain the nationwide GBT network for FAA. The single essential requirement would be to provide a continuous ADS-B service meeting the agency's performance specifications.

Such an approach would reduce pressure on the agency's capital budget and free the contractor of FAA's often gold-plated manufacturing criteria, which have produced major cost penalties in previous large system procurements. Certifiable signals in space would be the agency's key requirement. In other words the contractor would be responsible for the quality and availability of the uplinked signals and data, but would not be told how to provide them. In many ways, the contract would be analogous to FAA's current Flight Service Station arrangement with Lockheed Martin. However, if ADS-B's long-term, total cost is going to be far in excess of $1 billion, as some estimate, the system would be significantly more expensive.

According to informed observers, the RFO probably will call for responses within about 60 days, and a resulting contract award could be expected in August or September 2007. Some feel, however, that legal negotiations over the turnkey contract's costs and conditions could take longer. It is also unclear whether a major industry team will emerge as the leading contender. FAA has mentioned having "ad-hoc" discussions with Northrop Grumman, Rannoch, Sensis, ITT, Harris, Boeing and Lockheed Martin. The agency did not mention Raytheon, which normally bids on large FAA projects. Blakey has stated that ADS-B is expected to save $1 billion through the decommissioning of 200 surveillance radars, a major Raytheon activity.

It's difficult to say when the first of the new GBTs will commence operation. Companies like Sensis, Thales and Rannoch already have built and fielded GBTs in the United States, Australia and Mongolia, respectively, as well as several other locations. Other bidders may pick these firms as team members or decide to build their own designs, a longer process. However, the broad consensus is that the first new stations should begin operations in FY09 or FY10, and perhaps even earlier.

The location of the GBTs is an easier question to answer. FAA has stated that it plans to expand on the 40 current legacy GBTs along the east coast, in Alaska and at other central U.S. locations, gradually linking these with such high traffic areas as the west coast, the Great Lakes and the Ohio Valley, where ADS-B pioneer UPS operates hundreds of flights nightly. GBT coverage will then progressively expand, to cover the whole of the continental U.S. by FY14. According to the agency's proposed schedule, virtually all U.S. aircraft should be ADS-B-equipped by FY20.

The first area to receive GBT coverage will probably be the Gulf of Mexico, where offshore helicopter operators have long lacked low-altitude air traffic surveillance and weather services. When bad weather all but suspends operations--an average of 7,500 trips daily--the impact can be several million dollars a day. Following Blakey's announcement, FAA signed an agreement with the helicopter industry to provide Gulf-wide ADS-B coverage.

Based on as many as 20 offshore drilling platforms, these stations will perform a dual role. They will provide both universal access transceiver (UAT) signals to helicopters and Mode S signals for airline jets traversing the radar gap in the center of the Gulf. This gap in coverage forces air traffic control to use non-radar separation procedures, increasing flight time and fuel burn. Not only in the Gulf of Mexico, but "in many parts of the world, airlines lose millions through inefficient separation standards imposed by the lack of radar coverage," notes Jeff Brabender, president of Coherent Solutions. "ADS-B can finally correct this situation." Garmin and Free Flight already have general aviation systems flying in FAA's Alaska Capstone project and with operators like Embry-Riddle Aeronautical University, as well as many other government and private aircraft. The numbers of equipped aircraft undoubtedly will increase now that the project is officially under way. As Garmin marketing manager, Sam Seery, observes, "After being almost solitary ADS-B advocates for nearly 10 years, we are delighted to see the national program finally launched."

Airline avionics firms also have been busy, although somewhat less visible in the marketplace. Honeywell and Rockwell Collins, for example, have been adding ADS-B's "extended squitters" to their Mode S transponder responses to surveillance radar interrogations. These units then become so-called 1090ES models, capable of "ADS-B Out" transmissions from the aircraft, which provide additional data on controllers' screens.

At ACSS, communications manager, Steve Henden, expresses his company's view simply: "ACSS' future is tied to ADS-B." At UPS, ACSS has linked TCAS and Mode S units in the jet freighters to provide both "Out" and "In" signaling, enabling pilots to monitor proximate aircraft on the cockpit displays, a capability not yet available on most airline flight decks. Certainly the earliest air carrier in the world to capitalize on the benefits of ADS-B, UPS has also adopted ACSS' ADS-B SafeRoute system. According to Capt. Karen Lee, the company's director of flight operations, "At UPS, we're already living in the future as we see it, and it's a very bright place."

Further Issues

Yet the use of Mode S as an ADS-B medium is also under scrutiny for two reasons. First, the frequency is already showing signs of saturation in high-density airspace, and concerns have been expressed about its performance in the future, when traffic volumes are expected to double, and perhaps triple. Second, the limited 1090ES bandwidth prevents the reception of ADS-B's flight information services-broadcast (FIS-B) messages, including weather information. For many operators, this could be a serious drawback. One suggested solution is to develop small, standalone, airline-qualified UAT packages, which could offer full ADS-B benefits at a lower cost. This could also offer significant cost savings in the GBT network, where just those stations serving the main high-altitude traffic flows would need to carry 1090 transceivers alongside their UAT equivalents, while elsewhere the GBTs could carry only UAT transceivers. Another concern is the loss of GPS signals due to interference, satellite failure or other causes. An RTCA body has been charged with investigating GPS backup systems for ADS-B, and three of the potential candidates are eLoran (enhanced Loran), inertial systems and DME/DME.


ADS-B carriage will become mandatory, and an NPRM is expected as FAA gets closer to nationwide GBT coverage. However, like the mandates for TCAS, terrain awareness warning system (TAWS), reduced vertical separation minimum (RVSM) and similar systems, it is expected to be a graded application, covering various types of aircraft, classes of airspace and other factors. On the other hand, the future NGATS philosophy leans toward performance-based airspace access, where those who opt for full avionics equipage get priority handling, and those who opt for less equipment receive less expeditious handling, or are refused access to some parts of the airspace. At the same time, Blakey's statement that decommissioning secondary radar could save FAA around $1 billion has raised the notion in some quarters that some or all of these savings could be redistributed as equipment acquisition subsidies, thereby speeding the industry's transition to ADS-B and improving overall system efficiency.

Not unexpectedly, problems do arise when new operating concepts are introduced. Thus it was that, by a somewhat embarrassing coincidence, Blakey's launch announcement followed the earlier decision by FAA officials to remove ADS-B returns from the controllers' screens at the Anchorage en route center. It appeared that controllers had become concerned about safely discriminating between radar returns from conventional transponders and ADS-B signals from Capstone aircraft. This was particularly puzzling, since the controllers have experienced this condition since Capstone commenced in 2000, when Anchorage controllers were smoothly handling ADS-B and radar traffic (see February 2000, page 26). Equally puzzling was the fact that FAA apparently had never issued procedures to cover these situations.

Interestingly, Airservices Australia seems to have foreseen this problem when it launched its nationwide ADS-B network. Thales Australia, which supplied that nation's GBTs, recently reported that "the key benefit to Airservices controllers is that the transition of aircraft between radar and ADS-B was smooth and accurate." Since March 24, when FAA removed ADS-B targets from the Anchorage screens, the Alaska Aviation Coordination Council--which represents the state's commercial operators--had protested the move. By late May, with the ADS-B data still not replaced, the council announced that it would hold a June 2 media briefing to outline its concerns about the resulting reduction in safety. FAA immediately advised the council that the service would quickly be returned, with radar and ADS-B traffic separated using standards applicable to non-radar airspace. "Why couldn't they have simply told us that back in March?" asked one Alaska pilot. It might have been longer, according to one FAA source, who suggested that the agency's rapid action following the council's planned media event was in response to Blakey's reported annoyance upon hearing that the situation was still unresolved.

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