Q: How is the position of each airplane currently determined?
A: Since the 1940s, surveillance – or position information – has been provided to air traffic controllers by a nationwide system of radar stations. While radar has been the backbone of air traffic management for decades, it has several inherent deficiencies. First, radar is costly to install and maintain, requiring electro-mechanical units atop multiple towers located around the country. Second, radar is less effective in mountainous regions because the signals can be blocked by the terrain, and is not practical for oceanic coverage. Third, radar is relatively imprecise: radar antennas rotate at certain rates, resulting in positions displayed to the controller that may be up to several seconds old.
Q: What is ADS-B?
A: Automatic Dependent Surveillance Broadcast (ADS-B) technology is a revolutionary technology that has the potential to replace radar-based surveillance. An ADS-B -equipped airplane continually determines its precise location using a network of satellites and transmits a ‘data packet’ once per second, which includes information such as aircraft flight number, airspeed, type of aircraft and whether it is turning, climbing or descending. This data transmission is received by a network of ground stations and other equipped aircraft, and then sent on to an air traffic controller workstation, providing controllers and other aircraft a more precise location for each aircraft.
Q: What kinds of benefits does ADS-B offer?
A: The ADS-B position information that the controller receives is far more precise than today’s radar positioning. This offers a number of benefits.
The primary benefit of ADS-B is that it is a fundamental building block for the Next Generation National Airspace System (NextGen).
In addition, the ADS-B data packet sent to air traffic controllers can also be received by airlines and other parties to facilitate better system management by all users and service providers. In the near future, airplanes themselves can be equipped with an ADS-B receiver, which will enable real-time cockpit displays of weather and traffic, both on the ground and in the air. The positioning information displayed will allow each airplanes’ pilots to “see” other nearby airplanes. Ground vehicles can also be equipped with ADS-B, making them visible to controllers and pilots and reducing the risk of surface collisions.
Further, the precise positioning data delivered to controllers should safely enable reduced airplane separation standards, which would allow more aircraft to safely occupy a given volume of airspace, reducing congestion and delays. Additionally, more efficient routing enabled by ADS-B results in less fuel burn, and reduced emissions. Unlike radar, ADS-B data doesn’t degrade with distance or terrain.
Q: What are the components of ADS-B?
A: The basic surveillance system requires that each airplane be equipped with a GPS receiver and an ADS-B transponder. A ground network of small cabinet-sized ADS-B stations must also be installed. For future applications, airplanes must be equipped with ADS-B receivers and enhanced cockpit displays.
Q: Where has ADS-B been demonstrated?
A: The ADS-B concept was tested and demonstrated in Alaska’s Capstone Program, where mountainous terrain prohibited radar surveillance. The program was very successful and yielded significant efficiency and safety benefits for Alaska airplane operators by enabling pilots to see and avoid other aircraft.
Q: Is ADS-B currently in use?
A: UPS Airlines is leveraging the benefits of ADS-B at its Louisville, KY hub. In addition, other applications of ADS-B are used to various degrees in Canada (Hudson Bay), Australia, Sweden, New Zealand, Mongolia and Taiwan.
Q: Where else can we expect to see ADS-B used?
A: One of the first U.S. deployments of ADS-B will be in the Gulf of Mexico. Since radar isn’t practical for oceanic coverage, radar coverage in the Gulf today is limited to coastal areas. ADS-B equipment can be installed on oil platforms, providing gulfwide coverage and enabling aircraft spacing to be reduced from its current limit of 30 miles to just five miles. Other early applications of ADS-B will be in mountainous regions such as Colorado, where radar surveillance can be blocked by terrain, and in other test sites in Florida and Philadelphia. In October of 2007, the FAA issued a Notice of Proposed Rulemaking (NPRM) that would require aircraft to have ADS-B transponders onboard by 2020. The Federal Aviation Administration (FAA) has contracted with a consortium to install a nationwide system of ADS-B ground stations.
Q: What has the ADS-B ARC accomplished?
A: In October 2007, an ADS-B Aviation Rulemaking Committee (ARC) issued a report on optimizing the benefits of ADS-B. The ADS-B ARC then spent nine months evaluating the more than 1,400 public comments submitted in response to the ADS-B proposed rule. In September of 2008, the ADS-B ARC published a report that includes a set of recommendations for FAA intended to help resolve programmatic and technical issues and enable them to create a rule that yields benefits for all who operate in the nation’s airspace. A copy of this report is available online.
Q: Does the industry expect to meet the FAA proposed mandate to equip new aircraft by 2020?
A: Yes, and in fact the ADS-B ARC report identifies incentives that would encourage carriers to equip their fleets ahead of the proposed 2020 mandate.
Q: What issues still need to be addressed?
A: A number of technical challenges remain, such as international harmonization and interoperability, as well as frequency congestion and volume mitigation strategies.
Q: How much will this cost?
A: The FAA has published its own estimate of more than $1billion for a complete ground network system. Eventually, the FAA may recoup this investment by retiring unnecessary radar sites.
Airplane equipage costs for the airlines vary significantly depending on the age and configuration of the aircraft in their fleet. ATA estimates that the equipment will cost its member airlines – who currently operate 4,425 jet transports – more than $700 million to modify existing aircraft.
Q: How much money will ADS-B save?
A: As UPS Airlines’ success at its Louisville facility has demonstrated, there is potential for significant cost savings to airlines with respect to fuel savings and reduced delays. More systemwide savings could eventually be realized as conventional radar systems could be rendered unnecessary, and be eliminated. Eventually, aircraft collision- avoidance systems would also be candidates for elimination as they could also be incorporated into ADS-B technology. FAA estimated potential benefits at about $2.7 billion in 2007 dollars.
ATA strongly supports ADS-B technology, and an accelerated transition to NextGen. ATA consistently has expressed the view that ADS-B is a foundational technology for Next Gen. However, ATA is concerned that the ADS-B NPRM, if implemented as proposed, will not produce tangible benefits to airlines, (and by extension to the traveling and shipping public) but will, on the other hand, commit the aviation industry to enormous costs.
Q: Does ATA support ADS-B?
A: Yes, ADS-B is a critical component of the Next Generation National Airspace System (NextGen), which is strongly supported by ATA and its member airlines in order for the system to safely accommodate anticipated growth in air traffic. ATA believes that Congress and the FAA should make this program a priority. ATA is co-chair of the ADS-B Aviation Rulemaking Committee (ARC), and is working closely with the FAA and other industry stakeholders to refine an implementation strategy and provide practical recommendations to the FAA.