Air Transport Association (ATA) Position
ATA member airlines conceptually support a transition to an ADS-B based Air Traffic Control surveillance system. ADS-B as envisioned by the ATA will provide controllers with precision displays of airborne and surface traffic resulting in capacity increases through less restrictive separation standards. Air Traffic Controllers and user operational control centers will have access to the same information, to manage traffic flows and optimize surface movements. ADS-B will facilitate lower system costs by reducing or eliminating existing radar systems, and ADS-B will enable real time cockpit traffic displays that will support enhanced collision avoidance systems and, in some circumstances, permit pilot–controlled separation.
While the concept of ADS-B is promising, its feasibility for implementation will be determined by a detailed business case that reflects all costs and benefits for the user community and the FAA. In addition, a number of technical and regulatory challenges must be addressed, including international interoperability, frequency bandwidth and navigation source redundancy.
Background
The FAA's safety mandate requires all users to participate in the air traffic control system to ensure the safe separation of aircraft. The FAA is also charged with providing safe, efficient and expeditious movement of air traffic. Surveillance of aircraft in the airspace system is an essential requirement for the FAA to carry out this mission and is one of the largest FAA capital investment and operational expenses. Because of its effects upon airline safety and costs, FAA surveillance methods have significant implications to airlines.
Air traffic surveillance today is provided by modernized versions of rotating radars of the 1940s and 1950s, providing airplane positional information to air traffic controllers updated every 4.6 seconds near airports, and every 12 seconds in the en route system. Precision is limited by the nature of the technology, including low update rates, and transmission and processing delays. Conversely, ADS-B technology, coupled with Global Positioning System (GPS), provides a highly accurate, timely, all-weather, NAS-wide system of broadcasting geographical position, altitude and thrust vector from properly equipped aircraft and or surface vehicles. . Greater positional accuracy of ADS-B may allow closer spacing, permitting greater airspace capacity, safety and efficiency.
Economic and Operational Benefits
Implementing ADS-B in the U.S. airspace system will provide direct operating cost reductions to the FAA by replacing existing radar systems with less expensive ADS-B ground receiver stations. However, radar replacement will not offer users sufficient economic benefits to offset user equipage costs. In congested areas ADS-B potentially can provide additional capacity and efficiency through more accurate position data and reduced aircraft spacing. In addition, air-to-air applications have significant potential benefits including improved situational awareness, self-separation capability, improved safety through and a reduction in necessary ground infrastructure. Identifying, validating and quantifying user benefits will be instrumental in determining equipage timing and need.
Next Steps
Comments are under development in response to the notice of proposed rulemaking “Automatic Dependent Surveillance-Broadcast (ADS-B Out) Out performance requirements to support air traffic control (ATC) service. The comment period for the NPRM, published on October 5, 2007, closes March 3, 2008. ATA and its member airlines will continue to work closely with the FAA and the Joint Planning and Development Office (JPDO) to define the future NAS and its associated equipage requirements. Operational trials, such as those underway at Louisville and planned for the Gulf of Mexico will prove additional information to quantify the cost/benefits ADS-B.
January 2008
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