For an overview of ADS-B and General Aviation issues, watch this video (AeroNews Network, http://www.youtube.com/watch?v=pr2FmRAtIVA).


Background

NextGen includes six “transformational” programs: automatic dependent surveillance-broadcast (ADS-B), data communications (DataComm), System Wide Information Management (Swim), NextGen Network Enabled Weather, National Airspace System Voice Switch and Collaborative Air Traffic Management Technologies. It also depends on supporting efforts, including the $2.1 billion En Route Automation Modernization (Eram) program to replace computers at 20 FAA air route traffic control centers (FAA, 2007).
However, the Department of Transportation inspector general advised Congress in October 2011 that the costs, benefits and schedules of ADS-B, DataComm and Swim remain uncertain. And Eram has encountered significant software problems; it is expected to be completed four years late, in 2014, at an additional cost of $330 million (FAA, 2012c).
Nevertheless, the FAA is continues to implement core NextGen programs. Fifteen months after the FAA chartered it, the aviation rulemaking committee (ARC) tasked with developing a strategy for deploying ADS-B In, the capability to receive ADS-B traffic data on cockpit displays, submitted its recommendations to the agency in September. Emblematic of what one reported called “the one step forward, one step sideways progress of NextGen” (Collins, 2010), the ARC said it does not support equipping aircraft for ADS-B in at this time because the investment in displays and onboard computing cannot be justified. It is against this backdrop that future General Aviation access to the NAS must be evaluated.

ADS-B and General Aviation

ADS-B is an essential part of the planned NextGen airspace upgrade and will create better aircraft visibility at a lower overall cost than before. ADS-B equipment is built to meet one of two sets of US government standards, DO-260B and DO-282B (FAA, 2007b).
By the year 2020 all aircraft operating in the airspaces listed below will be required to carry equipment that produces an ADS-B Out broadcast. The FAA has published a rule requiring ADS-B Out transmitters in many types of airspace to take effect on January 1, 2020, but there is no mandate for ADS-B In, which receives data and provides it to in-cockpit displays (Carey, 2012).
ADS-B will offer increased safety, efficiency and environmental awareness for pilots and air traffic controllers at a lower overall cost that the current radar system. Companies have already begun selling and developing aircraft hardware systems to allow general aviation aircraft owners to equip at an affordable cost. Since the FAA has passed its final ruling on ADS-B, the uncertainty that prevented companies from producing hardware has been removed. The industry is seeing products being developed for all price points, low to high, and competitively priced equipment is nearing approval. As the technology matures more features are also becoming available creating even greater benefits for general aviation users (Collins, 2010).

Benefits of ADS-B for General Aviation

Improved situational awareness

  • Pilots in an ADS-B equipped cockpit will have the ability to see, on their in-cockpit flight display, other traffic operating in the airspace as well as access to clear and detailed weather information. They will also be able to receive pertinent updates ranging from temporary flight restrictions (TFRs) to runway closings.

Improved visibility

  • Even aircraft only equipped with ADS-B out will be benefited by air traffic controllers’ ability to more accurately and reliably monitor their position. Other fully equipped aircraft using the airspace around them will be able to more easily identify and avoid conflict with ADS-B out equipped aircraft.
  • ADS-B provides better surveillance in fringe areas of radar coverage. ADS-B does not have the siting limitations of radar. Its accuracy is consistent throughout the range.

Reduced environmental impact

  • ADS-B technology provides a more precise report of an aircraft's position. This allows controllers to guide aircraft into and out of crowded airspace with smaller separation standards than it was previously possible to do safely. This reduces the amount of time aircraft must spend waiting for clearances, being vectored for spacing and holding. ‍Estimates show that this is already having a beneficial impact by reducing pollution and fuel consumption (FAA, 2012).

ADS-B is intended to increase safety and efficiency. Safety benefits include:

  • Improved visual acquisition especially for general aviation under visual flight rules (VFR);
  • Reduced runway incursions on the ground

ADS-B enables increased capacity and efficiency by supporting:

  • Enhanced visual approaches
  • Closely spaced parallel approaches
  • Reduced spacing on final approach
  • Reduced aircraft separations
  • Enhanced operations in high altitude airspace for the incremental evolution of the "free flight" concept
  • Surface operations in lower visibility conditions
  • Near visual meteorological conditions (VMC) capacities throughout the airspace in most/all weather conditions
  • Improved ATC services in non-radar airspace
  • Trajectory-based operations providing a gently ascending and descending gradient with no step-downs or holding patterns needed. This will produce optimal trajectories with each aircraft becoming one node within a system wide information management network connecting all equipped parties in the air and on the ground. With all parties equipped with NextGen equipage, benefits will include reduced gate-to-gate travel times, increased runway utilization capacity, and increased efficiency with carbon conservation.

Concerns About the Rule

Most FAA rulemaking is safety-related, but the agency acknowledges that the ADS-B Out rule will not significantly affect safety. Instead, the mandate is intended to help NextGen ‍move‍ forward. “AOPA is not happy about this rule,” said Melissa Rudinger, AOPA senior vice president of government affairs. “We have supported transitioning through a benefits-driven process instead of a mandate—give us some benefits and [general aviation] will equip” (Carey, 2012).
Expanded coverage would be another potential incentive for GA aircraft owners to equip with ADS-B. The FAA is installing ADS-B infrastructure to provide coverage at least as good as existing radar. The industry has called for future expansion beyond the current radar service area. The FAA plans to complete installation of the nationwide ADS-B ground infrastructure by 2013 (FAA, 2012c).

Equipment and Datalink Options

‍The ADS-B equipment that is currently installed ‍in fewer than 1,000 aircraft does not meet the final rule’s requirements, although manufacturers believe most equipment could comply after upgrades or modification—engineers still are exploring their options. Eventually, ADS-B may eliminate the need for today’s Mode C transponders—but not in 2020. “The government still needs the transponder to fulfill their responsibility of traffic separation,” Rudinger said (Carey, 2012). Traffic Alert and Collision Avoidance System (TCAS) equipment installed on airliners and other primarily large aircraft rely on them. The FAA has indicated that transponders should become unnecessary sometime in the future, but has yet to specify the date.
Eventually aircraft owners will have to choose between benefits of the two ADS-B systems, the Universal Access Transceiver, a data link intended to serve the majority of the general aviation community using 978 MHz, or the Mode S 1090 MHz Extended Squitter (ES) broadcast link—the latter is a message the transponder broadcasts automatically, independent of any radar interrogation, over the busy 1090-MHz frequency.

A Less Expensive Option

In July 2010, the Soaring Society of America and the FAA, with support from AOPA, collaborated on proof-of-concept flight tests of a prototype low-cost, portable ADS-B transceiver. The prototype was built by MITRE, the private, not-for-profit engineering organization that developed UAT in the mid-1990s.
MITRE had been studying small, unmanned aircraft systems. “We looked at really miniaturizing the size, the weight, and the power requirements,” said Rob Strain, associate program manager for surveillance and broadcast applications. The 9.6-ounce prototype measures about 4 inches by 2 1/2 inches by 1/2 inch and includes a GPS receiver, temperature-compensated pressure sensor, antenna, and battery. Like other current ADS-B equipment, it doesn’t comply with the FAA’s recent ADS-B Out final rule.
The industry and AOPA would like to see transceivers priced below $2,000, and ideally closer to $1,000. The prototype’s low cost of parts should help keep the price down, if a manufacturer chooses to produce the design. Other products currently on the market are in that price range. NavWorx Inc. offers both portable and remote-mount ADS-B equipment priced from $1,500 to $2,700; SkyRadar’s portable receiver is $1,200 and shows TIS-B and FIS-B data on iPhones and other displays.
Many aircraft owners are wondering what to do in preparation for this mandate that becomes effective in slightly less than 10 years. The surprising advice from advocacy groups: ‍Do nothing. The next 12 to 18 months should provide new options and opportunities, allowing the owner/operators to educate themselves, keep up with developments in the arena, and allow the technology to mature before investing (Carey, 2012).

2030 – Future: A Perspective by David Freiwald

Moving forward to 2030 and beyond, it is inevitable that the General Aviation community will be forced to adopt NextGen technology and hardware improvements or lose access to vast areas of the National Airspace System. In the same way that Mode C transponders are necessary to access all but the smallest terminal areas for the past several decades,‍ so to will participation in NextGen services become necessary for general aviation to continue to have full access to the NAS.
Despite the desire for a global standardization it is unlikely that one will be formed which is then imposed by regulation upon the United States. Historically, GA advocacy and interest groups have proven highly effective in an obstructionist role when significant expense to their members is like to be borne as the result of regulatory action. More likely a scenario is envisioned where a minimum standard of participation is mandated in the United States forming a de facto standard for light aircraft as a result of market power.
‍Because of this projected scenario it is believed that UAT, the Universal Access Transceiver, will become the light aircraft standard while turbine aircraft will build upon existing technologies through the use of 1090ES to facilitate to European preference and eventual EASA requirement.‍ Given the FAA’s current commitment to a dual link system, this should allow light aircraft to participate in the majority of ADS-B In functionality and FIS-B services.
The rate of adoption will be driven entirely by economics; some owners and operators may find the equipment upgrades to be cost-prohibitive and opt for either reduced access or retirement of the asset, just as the operators of pre-electrical aircraft have done. This discussion has heretofore focused on the issue of access, implying the minimal standard necessary and therefore the lowest cost. Beyond the minimums for access, the limitations on functionality are solely a function of affordability. Just as there are four-place piston aircraft flying precision WAAS approaches today, there is nothing that is seen preventing the evolution of well-equipped aircraft from performing RNP approaches in the near future, let alone by 2030. Similarly, the use of electronic clearance delivery is expected to become the norm rather than the exception; indeed, the FAA has listed this as both a goal and as part of the template for future ATC staffing requirements.
While the FAA is supporting a push towards a fully digital, single-source solution by no means is the role of third-party providers necessarily imperiled. FIS-B services are very compelling and have been likened to a palliative for the costs of ADS-B implementation but they are not guaranteed in perpetuity. With user fees for ATC services more likely with each passing year and the recent decision to charge online services for access to navigation data, a scenario where the “feature” of NextGen becomes a commoditized seems likely. Just as Jeppesen charts remain as a more expensive but oft preferred option to the FAA’s own product, so too is a market likely to exist for third-party data solutions.
Given the current economic climate of the United States, as well as forecast for the next decade, it is highly unlikely that significant subsidies will be made available to general aviation, particularly at the lower end. By example, Section 221, NextGen public-private partnerships, of H.R. 658 was removed prior to passage. It is noteworthy that this section did not appear in the bill when originally introduced or when reported in the House, but only once it was passed, at which point fully 25% of the bill was changed. After being sent to the Senate and engrossed in amendment form, 95% of the original bill had been changed, including the deletion of Section 221.
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