[Federal Register Volume 72, Number 193 (Friday, October 5, 2007)]
[Proposed Rules]
[Pages 56947-56972]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 07-4938]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 91

[Docket No. FAA-2007-29305; Notice No. 07-15]
RIN 2120-AI92


Automatic Dependent Surveillance--Broadcast (ADS-B) Out 
Performance Requirements To Support Air Traffic Control (ATC) Service

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This notice proposes performance requirements for certain 
avionics equipment on aircraft operating in specified classes of 
airspace within the United States National Airspace System. The 
proposed rule would facilitate the use of Automatic Dependent 
Surveillance-Broadcast (ADS-B) for aircraft surveillance by Federal 
Aviation Administration and Department of Defense air traffic 
controllers to accommodate the expected increase in demand for air 
transportation. In addition to accommodating the anticipated increase 
in operations, this proposal, if adopted, would provide aircraft 
operators with a platform for additional flight applications and 
services.

DATES: Send your comments on or before January 3, 2008.

ADDRESSES: You may send comments identified by Docket Number FAA-2007-
29305 using any of the following methods:
    <bullet> Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the online instructions for sending your 
comments electronically.
    <bullet> Mail: Send comments to the Docket Management Facility; 
U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West 
Building Ground

[[Page 56948]]

Floor, Room W12-140, Washington, DC 20590-0001.
    <bullet> Hand Delivery or Courier: Bring comments to the Docket 
Management Facility in Room W12-140 of the West Building Ground Floor 
at 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 
p.m., Monday through Friday, except Federal holidays.
    <bullet> Fax: Fax comments to the Docket Management Facility at 
202-493-2251.
    Privacy Act: We will post all comments we receive, without change, 
to http://www.regulations.gov, including any personal information you 
provide. Anyone is able to search the electronic form of all comments 
received into any of our dockets by the name of the individual 
submitting the comment (or signing the comment, if submitted on behalf 
of an association, business, labor union, etc.). You may review DOT's 
complete Privacy Act Statement in the Federal Register published on 
April 11, 2000 (65 FR 19477-78) or you may visit http://DocketInfo.dot.gov.
    Docket: To read background documents or comments received, go to 
http://www.regulations.gov at any time and follow the online 
instructions for accessing the docket. Or, go to the Docket Management 
Facility in Room W12-140 of the West Building Ground Floor at 1200 New 
Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Vincent Capezzuto, Surveillance and 
Broadcast Services Office, Air Traffic Organization, Federal Aviation 
Administration, 800 Independence Avenue SW., Washington, DC 20591; 
telephone 202-385-8288.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites interested persons to participate in this 
rulemaking proposal by submitting written comments, data, or views. We 
also invite comments relating to the economic, environmental, energy, 
or federalism impacts that might result from adopting the proposals in 
this document. The most helpful comments reference a specific portion 
of the proposal, explain the reason for any recommended change, include 
specific rule language changes, and include supporting data. We ask 
that you send us two copies of written comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning this proposed rulemaking.
    Before acting on this proposal, we will consider all comments we 
receive on or before the closing date for comments. We will consider 
comments filed after the comment period has closed if it is possible to 
do so without incurring expense or delay. We may change this proposal 
in light of the comments we receive.
    If you want the FAA to acknowledge receipt of your comments on this 
proposal, include with your comments a pre-addressed, stamped postcard 
on which the docket number appears. We will stamp the date on the 
postcard and mail it to you.

Proprietary or Confidential Business Information

    Do not file in the docket information that you consider to be 
proprietary or confidential business information. Send or deliver this 
information directly to the person identified in the FOR FURTHER 
INFORMATION CONTACT section of this document. You must mark the 
information that you consider proprietary or confidential. If you send 
the information on a disk or CD-ROM, mark the outside of the disk or 
CD-ROM and also identify electronically within the disk or CD-ROM the 
specific information that is proprietary or confidential.
    Under 14 CFR 11.35(b), when we are aware of proprietary information 
filed with a comment, we do not place it in the docket. We hold it in a 
separate file to which the public does not have access, and place a 
note in the docket that we have received it. If we receive a request to 
examine or copy this information, we treat it as any other request 
under the Freedom of Information Act (5 U.S.C. 552). We process such a 
request under the DOT procedures found in 49 CFR part 7.

Availability of Rulemaking Documents

    You can get an electronic copy of rulemaking documents using the 
Internet by--
    1. Searching the Federal eRulemaking Portal (http://www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies Web page at http://www.faa.gov/regulations_policies/; or
    3. Accessing the Government Printing Office's Web page at http://www.gpoaccess.gov/fr/index.html.
    You can also get a copy by sending a request to the Federal 
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence 
Avenue, SW., Washington, DC 20591, or by calling (202) 267-9680. Make 
sure to identify the docket number, notice number, or amendment number 
of this rulemaking.

Authority for This Rulemaking

    The FAA's authority to issue rules regarding aviation safety is 
found in Title 49 of the United States Code. Subtitle I, Section 106 
describes the authority of the FAA Administrator. Subtitle VII, 
Aviation Programs, describes in more detail the scope of the agency's 
authority.
    This rulemaking is promulgated under the authority described in 
Subtitle VII, Part A, Subpart I, Section 40103, Sovereignty and use of 
airspace, and Subpart III, section 44701, General requirements. Under 
section 40103, the FAA is charged with prescribing regulations on the 
flight of aircraft, including regulations on safe altitudes, 
navigating, protecting, and identifying aircraft, and the safe and 
efficient use of the navigable airspace. Under section 44701, the FAA 
is charged with promoting safe flight of civil aircraft in air commerce 
by prescribing regulations for practices, methods, and procedures the 
Administrator finds necessary for safety in air commerce.
    This proposal is within the scope of sections 40103 and 44701 since 
it proposes aircraft performance requirements that would meet advanced 
surveillance needs to accommodate the projected increase in operations 
within the National Airspace System (NAS). As more aircraft operate 
within the U.S. airspace, improved surveillance performance is 
necessary to continue to balance the growth in air transportation with 
the agency's mandate for a safe and efficient air transportation 
system.

Table of Contents

I. Background
    A. Vision of the Future
    B. The Century of Aviation Reauthorization Act and NextGen
    C. Today's Radar Environment
II. The ADS-B System
    A. General
    B. Ground Infrastructure
III. Summary of the Proposal
IV. The Proposal for ADS-B Out
    A. Advantages of ADS-B Out
    B. Avionics
    1. 1090ES and UAT Broadcast Links
    2. Broadcast Link Requirements for Different Flight Levels
    3. Part 91 Appendix H Message Elements
    4. Navigation Position Sensor and the Accuracy and Integrity of 
the ADS-B Message
    5. ADS-B Antenna Diversity and Transmit Power Requirements
    6. Latency of the ADS-B Out Broadcast Message Elements
    7. Maintenance
    C. Operational Procedures
    1. Applicability
    2. Airspace
    3. Pilot Procedures
    4. Backup Surveillance Strategy

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    5. Compliance Schedule for ADS-B Out Requirements
V. ADS-B In
    A. Avionics
    B. Applications and Services
VI. FAA Experience with ADS-B
    A. Capstone
    B. Gulf of Mexico
    C. UPS--Louisville
    D. Surveillance in Non-Radar Airspace
VII. ADS-B in Other Countries
VIII. Alternatives to ADS-B
IX. Rulemaking Notices and Analyses

I. Background

A. Vision of the Future

    The demand for air travel is growing in the U.S. and around the 
world. The FAA's forecasts project a doubling in U.S. airline passenger 
traffic by 2025. The forecasts also show strong growth for general 
aviation, especially with the advent of very light jets. By the end of 
this decade as many as 400-500 of these small jets could join the fleet 
each year. With the new small jets and other growth, the active general 
aviation fleet is projected to grow from 230,000 aircraft today to 
275,000 aircraft in 2020.
    That is the demand from piloted aircraft. The development and use 
of unmanned aircraft systems (UAS) is one of the next big steps forward 
in aviation's evolution. The FAA is working across government and 
industry to ensure the safe authorization of these aircraft to fly in 
civil airspace.
    The good news is U.S. air travel and related use of the National 
Airspace System (NAS) will grow. That growth will bring challenges 
since the present U.S. air traffic system--the world's largest and 
safest--is not designed to absorb this level of growth. Today's system 
is limited by outmoded technology--such as the constraints ground-based 
radar places on the distance aircraft must be separated and the limits 
caused by having to transmit information by voice between aircraft and 
the ground.
    The solution to managing the anticipated growth in the use of the 
NAS is the Next Generation Air Transportation System, or NextGen, which 
will assure the safe and efficient movement of people and goods as 
demand increases. NextGen will use technology to allow precise 
navigation, permit accurate real-time communication, and vastly improve 
situational awareness. The goal: A system flexible enough to 
accommodate safely whatever number, type and mix of aircraft there will 
be in U.S. skies by 2025.
    NextGen will be an aircraft-centric system with performance-based 
requirements. The future system will describe performance for 
navigation, communications, and surveillance.
    For navigation, the aviation community is already seeing the 
benefits of performance-based navigation with the use of Required 
Navigation Performance (RNP) as well as Area Navigation (RNAV) 
procedures at many U.S. airports. RNP and RNAV are examples of 
procedures that use improved navigational accuracy as compared to 
traditional procedures. The new procedures are being implemented 
consistent with the ``Roadmap for Performance-Based Navigation.'' The 
benefit of performance-based navigation: Enabling aircraft to fly 
precisely defined flight paths with unprecedented accuracy.
    For communication, NextGen will be built on a more comprehensive 
and capable information network than has been previously available. It 
will ensure the right information gets to the right person at the right 
time. With performance-based navigation and internet-like access to 
critical information--including nearly real-time weather--pilots will 
be able to make precision landings at airports that have no control 
towers, radar, or Instrument Landing Systems. Attaining the goal of 
performance-based communications will depend on technology, such as 
datalink, which would transmit key instructions directly to aircraft 
flight management systems, which would speed receipt of critical 
information and prevent errors that can come from manual data entry.
    The third element--performance-based surveillance--relies on 
technology that permits knowing the exact location of other aircraft in 
the air and of other aircraft and ground vehicles on the airport 
surface. The aviation community's experience with ADS-B, which 
periodically broadcasts an aircraft's location--both horizontal and 
vertical position and horizontal and vertical velocity--will lead 
directly to the performance requirements. When displayed in the 
cockpit, information obtained through ADS-B greatly improves 
situational awareness in the en route segment, in the terminal area 
during approaches, and on the airport surface. For additional 
information on ADS-B activities, see Section VI, FAA Experience with 
ADS-B later in the preamble.
    This rulemaking is important because ADS-B is an essential NextGen 
building block. Improving surveillance requires advanced onboard 
equipment with backup capability. Most, if not all, of the surveillance 
capability as well as the navigation and communications capabilities 
should be onboard the aircraft so the required capabilities will go 
wherever the aircraft goes. As part of the rulemaking effort, the FAA 
established an Aviation Rulemaking Committee under Order 1110.147. This 
committee has been chartered to deliver a report on how to optimize 
operational benefits of the ADS-B system and to provide recommendations 
to the FAA on the rulemaking after the NPRM is published. The scope of 
the ARC membership is designed to provide the widest range of inputs 
into the development of the NextGen strategy. The FAA will put the ARC 
recommendations in the docket established for this rulemaking.
    It is this combination of onboard capability and performance 
expectations that will enable aircraft in the future to fly safely and 
efficiently despite ever-increasing demands on the airspace.

B. The Century of Aviation Reauthorization Act and NextGen

    The ``Century of Aviation Reauthorization Act'' was enacted on 
December 12, 2003 (Pub. L. 108-176) (the ``Act''). This law set forth 
requirements and objectives for transforming the U.S. air 
transportation system to meet the needs of the 21st Century. Section 
709 of the Act required the Secretary of Transportation to establish in 
the FAA a joint planning and development office (JPDO) to manage work 
related to NextGen. Among its statutorily defined responsibilities, the 
JPDO coordinates the development and utilization of new technologies to 
ensure that when available, they may be used to the fullest potential 
in aircraft and in the air traffic control system.
    The FAA, the National Aeronautics and Space Administration (NASA) 
and the Departments of Commerce, Defense, and Homeland Security have 
launched an effort to align their resources to develop and further 
evolve NextGen. The goals of NextGen, as stated in the Act, that are 
addressed by this proposal are:
    (1) Improve the level of safety, security, efficiency, quality, and 
affordability of the NAS and aviation services;
    (2) Take advantage of data from emerging ground-based and space-
based communications, navigation, and surveillance technologies;
    (3) Be scalable to accommodate and encourage substantial growth in 
domestic and international transportation and anticipate and 
accommodate continuing technology upgrades and advances; and
    (4) Accommodate a wide range of aircraft operations, including 
airlines,

[[Page 56950]]

air taxis, helicopters, general aviation, and UAS.
    The JPDO was also charged with creating and carrying out an 
integrated plan for NextGen. The Act mandates that the NextGen 
Integrated Plan (the ``Plan'') be designed to ensure that the NextGen 
system meets the air transportation safety, security, mobility, 
efficiency, and capacity needs beyond those currently included in the 
FAA's Operational Evolution Plan.\1\ As described in the Plan \2\, the 
current approach to air transportation, where ground based radars track 
flights along congested airways, and pass information among the control 
centers for the duration of the flights, is becoming operationally 
obsolete. The current system is increasingly inefficient, and large 
increases in air traffic will result in mounting delays or limitations 
in service for many areas in the NAS.
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    \1\ The Plan was submitted to Congress on December 12, 2004.
    \2\ A copy of the Plan has been placed in the docket for this 
rulemaking.
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    As detailed in the Plan, the demand for air travel is expected to 
double within the next 20 years. Current FAA projections are that by 
2025, operations will grow to more than half a million departures and 
arrivals per year at approximately 16 additional airports. The present 
air traffic control system will be unable to handle this level of 
growth. Not only will the current method of handling traffic flow not 
be able to adapt to the highest volume and density for future 
operations, but the nature of the new growth may be problematic, as 
future aviation activity will be much more diverse than it is today. A 
shift of 2 percent of today's commercial passengers to very light jets 
that seat 4-6 passengers would result in triple the number of flights 
necessary to carry the same number of passengers.\3\ Furthermore, the 
challenges grow with the advent of other non-conventional aircraft, 
such as the UAS.
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    \3\ Very light jets may revolutionize the industry by permitting 
more individuals and corporations to own aircraft. It addition, many 
airports that are too small for large jet operations should benefit 
because they can support very light jets.
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    The future of air transportation contemplated in the Plan is 
complex, and the FAA believes that ADS-B technology is a key component 
in achieving many of the goals set forth in the Plan. This proposed 
rule embraces a new approach to surveillance performance requirements 
that can lead to greater and more efficient use of airspace. The Plan 
articulates several large transformation strategies to create the 
NextGen System. This proposal is a major step toward strategically 
``establishing an agile air traffic system that accommodates future 
requirements and readily responds to shifts in demand from all users.'' 
ADS-B technology will assist in the transition to a system with less 
dependence on ground infrastructure and facilities, and would provide 
for more efficient use of airspace.

C. Today's Radar Environment

    In the U.S., Air Traffic Control (ATC) surveillance and aircraft 
separation services are provided by the use of primary and secondary 
surveillance radar systems. While radar technology has advanced, it is 
essentially a product of 1940s World War II technology. Both primary 
and secondary radars are very large structures that are expensive to 
deploy and maintain; they also require the agency to lease land for 
site installation.
    Primary radar is a passive detection method that requires no 
special equipment aboard the aircraft. It is a technology that 
transmits a beam that is reflected by a target. This reflection forms a 
return signal that is translated into an aircraft position by ATC 
automation systems. Primary radar, however, is not always able to 
distinguish aircraft from other objects that reflect radar beams, such 
as birds or severe weather, which can result in ``clutter'' on the ATC 
radar scope. In addition, with primary radar, ATC is provided only with 
an aircraft's position relative to time. It does not provide any other 
information about the aircraft.
    Primary radar measures both the range and bearing of a particular 
aircraft. Bearing is measured by the position of the rotating radar 
antenna when it receives a response to its signal that is reflected 
from the aircraft. Range is measured by the time it takes for the radar 
to receive the reflected response. Detecting changes in an aircraft's 
velocity requires several radar sweeps that are spaced several seconds 
apart. Because the antenna beam becomes wider as the aircraft travels 
farther away from the radar, the accuracy of the radar is a function of 
range, and the accuracy decreases as the distance between the aircraft 
and the radar site increases. Consequently, aircraft on the outer 
fringes of radar coverage or in non-radar areas are separated by 
greater distances, directly affecting efficiency and ultimately 
capacity in the NAS.
    A Secondary Surveillance Radar (SSR) system consists of antennas, 
transmitters, and processors installed in ATC facilities, and radio 
transponder devices that are installed in aircraft. This system 
enhances primary radar by improving the ability to detect and identify 
aircraft. An SSR transmits interrogation pulses that elicit responses 
from transponders on board the aircraft. A transponder installed on the 
aircraft ``listens'' for the interrogation signal and sends back a 
reply that provides aircraft information. The aircraft is then 
displayed as a tagged icon on the air traffic controller's radar 
screen.\4\
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    \4\ An aircraft without an operating transponder may still be 
observed by ATC using primary radar, but the aircraft will not have 
an identifying tag.
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    Each transponder category has unique characteristics, operating 
functions, and requirements. A transponder with Mode A functionality 
requires the pilot to input a discrete code. If the same transponder is 
connected with an encoding device then it will also report the 
aircraft's altitude (Mode C). Most aircraft operated in general 
aviation have Mode A/C transponders. Any aircraft required to have 
Traffic Alert and Collision Avoidance System (TCAS) II, or that 
voluntarily has TCAS II installed must also be equipped with a Mode S 
Transponder. (This generally includes aircraft operated under parts 
121, 125, 129 and some aircraft operated under part 135.) Mode S 
transponders transmit both aircraft altitude and aircraft 
identification information. Both Mode A/C transponders and Mode S 
transponders require interrogation to provide information.
    To accommodate the projected level of traffic without increasing 
delay, more comprehensive surveillance in the NAS, including more radar 
sites in certain areas, would be necessary. Even if more radar sites 
were commissioned, however, there are many areas in which radar 
coverage is not feasible, either geographically (e.g., mountainous 
areas) or in a cost-effective manner (e.g., remote areas). Furthermore, 
simply increasing the number of radars in the NAS does not solve the 
inherent limitation of radar technology, and would not allow the FAA to 
reduce current separation standards.\5\ Consequently, the future of air 
traffic surveillance cannot be based solely on the use of radar. Radar 
technology also lacks the capability to provide services on the flight 
deck. However, the FAA is planning to maintain its current network of 
primary radars, and expects to be able to reduce a percentage of its 
secondary radars. This NPRM does not propose to reduce primary radar 
sites.\6\

[[Page 56951]]

Instead, this NPRM would transfer future aircraft surveillance to newer 
and more advanced onboard avionics that provide more accurate and 
timely aircraft information. ADS-B has been identified as the 
technology to facilitate that goal.
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    \5\ The FAA currently separates aircraft by 5 NM in the en route 
environment and 3 NM in the terminal environment.
    \6\ While the FAA expects to be able to reduce a significant 
percentage of the national secondary surveillance radar 
infrastructure, primary radars will not be decommissioned as a 
function of this proposal. Primary radar will serve a role in 
surveillance during the transition period of ADS-B avionics 
equipage.
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II. The ADS-B System

A. General

    The ADS-B system is an advanced surveillance technology that 
combines a satellite positioning service, aircraft avionics, and ground 
infrastructure to enable more accurate transmission of information 
between aircraft and ATC. The system enables equipped aircraft to 
continually broadcast information, such as identification, current 
position, altitude, and velocity. ADS-B uses information from a 
position service, e.g. Global Positioning System (GPS), to broadcast 
the aircraft's location, thereby making this information more timely 
and accurate than the information provided by the conventional radar 
system (which has a latency factor since it is based on interrogation 
and reply). ADS-B also can provide the platform for aircraft to receive 
various types of information, including ADS-B transmissions from other 
equipped aircraft or vehicles. ADS-B is automatic because no external 
interrogation is required, but is ``dependent'' because it relies on 
onboard position sources and onboard broadcast transmission systems to 
provide surveillance information to ATC and ultimately to other users.
    Implementation of an ADS-B system would not completely replace the 
primary radar or SSR at this time. In addition, ADS-B does not replace 
the requirement for transponders. Transponders are still necessary for 
SSR, which is the FAA's backup strategy in case of ADS-B failure. For 
more information on the backup strategy, see section IV.C.4, Backup 
Surveillance Strategy.
    The performance requirements for ADS-B avionics proposed in this 
NPRM would ensure that the aircraft is broadcasting the requisite 
information with the degree of accuracy and integrity necessary for ATC 
to use that information for surveillance.\7\ This enhanced surveillance 
would provide ATC with the enhanced ability to surveil and separate 
aircraft so that efficiency and capacity could increase beyond current 
levels to meet the predicted demand for ATC services while continually 
maintaining safety. Incremental developments in capacity, efficiency, 
and air traffic control procedures based on radar technology cannot 
accommodate the anticipated increase in demand for surveillance and 
separation services, which could result in delays that would far exceed 
those experienced today. Without ADS-B, the increase in demand could 
result in increased congestion and the denial of ATC service to some 
users of the NAS.
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    \7\ An aircraft equipped for ADS-B Out would transmit the 
aircraft's position, velocity and other specified, proposed message 
elements once per second. Radar data, on the other hand, is 
generated approximately once every 3-12 seconds for display to the 
air traffic controller depending on whether the aircraft is in the 
en route or terminal environment.
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    ADS-B technology already has been demonstrated successfully in 
Alaska via the Capstone program.\8\ In Alaska, radar coverage is either 
very limited or non-existent. ADS-B provides a level of surveillance 
performance that previously did not exist and has resulted in increases 
in both efficiency and capacity.
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    \8\ For additional information on Capstone, see Section VI. 
later in the preamble. It should be noted that Special Federal 
Aviation Regulation No. 97, Special Operating Rules for the Conduct 
of Instrument Flight Rules (IFR) Area Navigation (RNAV) Operations 
Using Global Positioning Systems (GPS) in Alaska (68 FR 14072; March 
21, 2003), would remain in effect to supplement the requirements in 
this proposal as it applies to Alaska.
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    ``ADS-B Out'' refers to an appropriately equipped aircraft's 
broadcasting of various aircraft information. ``ADS-B In'' refers to an 
appropriately equipped aircraft's ability to receive another aircraft's 
ADS-B Out information. This proposal only seeks to require ADS-B Out; 
the FAA is not proposing to require ADS-B In at this time.\9\
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    \9\ See Sections IV. later in the preamble for a detailed 
discussion of ADS-B Out and V. for a detailed discussion of ADS-B 
In.
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B. Ground Infrastructure

    Implementing ADS-B in the NAS to provide surveillance requires 
avionics, ground infrastructure, automation, and data. This NPRM 
addresses the performance requirements for the avionics and the 
necessary data that must be broadcast from the aircraft in order for 
ATC to use that information for surveillance and separation. The ground 
infrastructure involves the installation of a multitude of ground 
stations throughout the NAS that first receive the ADS-B Out 
transmissions from an aircraft, then relay real-time information based 
on those transmissions to ATC facilities. The exact number of ground 
stations needed to provide broadcast services across the NAS will be 
negotiated as part of the national broadcast service contract. The 
preliminary estimate approved by the FAA's Joint Resource Council call 
for 548 ground stations to provide coverage NAS-wide and in the Gulf of 
Mexico.
    On August 30, 2007, the FAA awarded a performance-based service 
contract to a consortium led by ITT Corporation. The contract is to 
provide ADS-B surveillance uplink (ground-to-air) and downlink (air-to-
ground) services and Automatic Dependent Surveillance Rebroadcast (ADS-
R), Traffic Information Services--Broadcast (TIS-B) \10\, and Flight 
Information Services--Broadcast (FIS-B) \11\ services. The vendor will 
install and maintain the ground equipment necessary to provide ADS-B 
uplink and downlink services to ATC. On November, 30, 2006, the FAA 
issued a Screening Information Request to determine which vendors 
understand the contract requirements well enough to proceed in the 
acquisition process. The FAA's schedule for ADS-B Out calls for all 
ground infrastructure, including the provision of broadcast services, 
to be in place and available where current surveillance exists by the 
end of fiscal year 2013. This schedule will provide reasonably ample 
time for operators to equip their aircraft for ADS-B Out and meet the 
proposed compliance date of 2020 in this notice.
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    \10\ Traffic Information Services--Broadcast (TIS-B) is a 
ground-based uplink report to a pilot of proximate traffic that is 
under surveillance by ATC but is not ADS-B-equipped. This service 
would be available even with limited ADS-B implementation. The 
combinations of the surveillance and TIS-B services can enable 
pilots to have enhanced visual acquisition of other aircraft. Having 
traffic and other flight obstacles on a cockpit display will enable 
pilots to more quickly identify safety hazards and communicate with 
ATC if necessary. Aircraft that are equipped with ADS-B can be 
monitored through a direct reception of their ADS-B signals in an 
air-to-air environment.
    \11\ Flight Information Services--Broadcast (FIS-B) is a ground-
based uplink of flight information services and weather data. Other 
flight information provided by the FIS-B service includes Notices to 
Airmen and Temporary Flight Restrictions.
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III. Summary of the Proposal

    The FAA is proposing ADS-B Out performance requirements for all 
aircraft operations in Class A, B, and C airspace areas in the NAS, and 
Class E airspace areas at or above 10,000 feet mean sea level (MSL) 
over the 48 contiguous United States and the District of Columbia. This 
proposal also would require that aircraft meet these performance 
requirements in the airspace out to 30 nautical miles (NM), from the 
surface up to 10,000 MSL, around certain identified airports that are 
among the nation's busiest. In addition, this proposal if adopted would 
require that aircraft meet ADS-B Out performance requirements to 
operate in

[[Page 56952]]

Class E airspace over the Gulf of Mexico from the coastline of the 
United States out to 12 nautical miles (NM), at and above 3,000 feet 
MSL.
    The FAA proposes to require aircraft flying at or above Flight 
Level 240 (FL240) to have ADS-B Out performance capabilities using the 
1090 Extended Squitter (1090ES) broadcast link. Aircraft flying in the 
designated airspace below FL 240 would have to use either the 1090ES or 
Universal Access Transceiver (UAT) broadcast link. These proposals 
would affect all U.S. commercial air carrier operations, foreign-flag 
carriers operating in the designated classes of U.S. airspace, air 
charter operations, air cargo operations, and a significant portion of 
the general aviation fleet operating in the NAS.
    The implementation of ADS-B requires two datalinks to support the 
full set of applications. UAT is intended to support applications for 
the general aviation user community that are not needed by air carriers 
because air carriers have weather radar, fly at high altitudes, and 
have other aeronautical links. UAT-equipped general aviation aircraft 
are not generally equipped with weather radar and would be flying at 
low altitudes. The 1090ES link is the internationally agreed upon link 
for ADS-B, and is intended to support applications for air carriers and 
other high-performance aircraft. The 1090ES broadcast link does not 
support applications available from FIS-B, like weather and related 
flight information. This is because of the bandwidth limitations of the 
1090ES link for transmitting the large message structures required by 
FIS-B. Weather and flight information for 1090ES-equipped aircraft is 
generally provided by commercial products.
    As described in the Plan, large increases in air traffic would 
result in mounting delays or limitations in service for many areas if 
the current surveillance system is not modified. An environment in 
which aircraft meet the proposed ADS-B Out performance requirements 
would result in greater capacity and efficiency in the NAS, maintain 
safety, and provide a flexible, expandable platform to accommodate 
future traffic growth while avoiding possible system delays and 
limitations in service.
    In moving forward with a performance-based surveillance system, the 
FAA believes that communication with the affected industry is critical. 
The FAA hosted several Industry Days to brief the technology, the 
rulemaking and procurement processes and associated milestones to 
interested parties, including manufacturers and affected operators. As 
with any rulemaking, the FAA invites comments on the various elements 
of this proposal, and all comments will be carefully considered. If 
this proposal is adopted as a final rule, it may be modified in view of 
the submitted comments.

IV. The Proposal for ADS-B Out

A. Advantages of ADS-B Out

    ADS-B Out, as proposed in this notice, would enhance surveillance 
and broadcast services in both the en route and terminal environments 
and provide ATC with more accurate information to safely separate 
aircraft in the air.
    In today's radar surveillance environment, accuracy and integrity 
of radar information is a function of range and decreases as the 
distance between the radar antenna and the aircraft increases. Unlike 
radar, both the accuracy and integrity of ADS-B Out is uniform and 
consistent throughout the service area. A comprehensive, national 
surveillance system that utilizes ADS-B Out would provide ATC with the 
ability to accurately identify and locate aircraft that are either far 
away from the ATC facilities or at the outer boundaries of ground 
station service volume.
    If ATC had more precise aircraft position information, it could 
position, separate, and provide speed and direction instructions to 
aircraft with improved precision and timing. This would result in the 
use of optimal flight paths and altitudes. This transmission of 
information would enable improvement of airspace capacity throughout 
the NAS. Additionally, with ADS-B Out, ATC would receive updated 
information broadcast by aircraft more frequently than with radar, and 
would be able to track a more closely monitored flight path. This would 
result in ATC providing fewer instructions to pilots, thus having more 
time to accommodate additional aircraft within the allotted airspace. 
These improved efficiencies for ATC ultimately should accommodate the 
increased number of aircraft able to operate in the NAS. In addition, 
we expect a reduction in aircraft fuel burn because better surveillance 
provides for more efficient use of the airspace, provides for optimal 
aircraft routing, and addresses the limits currently experienced with 
radar.
    In the terminal radar environment today, ATC may have to request 
pilots to provide aircraft speed, heading, and in some cases, aircraft 
identification. Neither the primary radar nor SSR systems provide all 
that information. With ADS-B, ATC is automatically provided aircraft 
speed, heading, and other identifying information, including aircraft 
size, which are necessary to safely position and separate aircraft more 
rapidly than is possible today.
    While more precise ADS-B derived aircraft position information 
improves ATC efficiencies under current separation standards, the 
potential for significantly greater capacity and efficiency gains may 
be realized by reducing separation standards between aircraft. 
Therefore, this rulemaking is expected to help achieve a level of 
surveillance accuracy that would support reducing aircraft separation 
standards. ADS-B is an essential component of the NextGen platform and 
is necessary to achieve a level of capacity in the NAS commensurate 
with future growth.

B. Avionics

    This discussion first addresses the broadcast message links 
necessary to transmit aircraft information to the ground stations and 
the specific message elements that would be broadcast by the aircraft 
comprising the ADS-B Out transmission. Next we discuss the navigation 
position sensor and the necessary accuracy and integrity of the ADS-B 
message. Finally, we explain the necessary requirements for antenna 
diversity on the aircraft, and the required latency of the data in the 
ADS-B transmission from the aircraft.
1. 1090ES and UAT Broadcast Links
    In 2002, the United States determined that two frequencies would be 
appropriate for ADS-B: 1090MHz and 978MHz. To broadcast the necessary 
data elements for ADS-B Out transmission under this proposal, aircraft 
would have to be equipped with either 1090ES or UAT that meet the 
latest version of either Technical Standard Order (TSO)-C166a or TSO-
C154b, respectively.\12\ Today, operators of air carriers and many 
private/commercial aircraft already are primarily equipped with 
avionics designed under TSO-C112, Air Traffic Control Radar Beacon 
System/Mode Select (ATCRBS/Mode S), which are required to function with 
the Traffic Alert and Collision Avoidance System

[[Page 56953]]

(TCAS II) or ACAS.\13\ Many TSO-C112 Mode S Transponders can be 
modified or are designed to provide 1090ES functionality under TSO-
C166a. Most other general aviation aircraft, typically small aircraft 
operated in non-commercial service (that are not required to have TCAS 
II), would likely use the UAT broadcast link for ADS-B Out, which 
operates on the 978MHz frequency. Today, a small number of aircraft are 
equipped with UAT ADS-B In and are capable of receiving TIS-B and FIS-B 
services. While the 1090ES link does not support FIS-B, it does support 
TIS-B.
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    \12\ A TSO is a minimum performance standard issued by the 
Administrator for specified materials, parts, processes, and 
appliances used on civil aircraft. TSO-C166a sets the minimum 
performance standards for Extended Squitter Automatic Dependent 
Surveillance--Broadcast (ADS-B) and Traffic Information Service 
Broadcast (TIS-B) Equipment Operating on the Radio Frequency of 1090 
MHz. TSO-C154b sets the minimum performance standard for Universal 
Access Transceiver (UAT) Automatic Dependent Surveillance-- 
Broadcast (ADS-B) Equipment.
    \13\ Airborne Collision Avoidance System (ACAS) is comparable to 
TCAS II and is specified for use in Europe.
---------------------------------------------------------------------------

    In December 2006, RTCA \14\ published RTCA/DO-260A, Change 2, 
``Minimum Operational Performance Standards (MOPS) for 1090 MHz 
Automatic Dependent Surveillance--Broadcast (ADS-B).'' This change 
revised RTCA/DO-260 1090ES MOPS. The major differences between RTCA/DO-
260 and RTCA/ DO-260A are refinements of the Navigation Integrity 
Category (NIC), Navigation Accuracy Category (NAC), and Surveillance 
Integrity Level (SIL) parameters, which significantly improve the 
overall performance and interoperability of the ADS-B Out broadcast 
link. These modified parameters (NIC, NAC, and SIL) provide a level of 
accuracy and integrity with respect to the information transmitted in 
the ADS-B Out message that would enable ATC to provide improved 
surveillance and separation services based on the information it 
receives from the aircraft.
---------------------------------------------------------------------------

    \14\ RTCA, Incorporated is a not-for-profit corporation formed 
to advance the art and science of aviation and aviation electronic 
systems for the benefit of the public. The organization functions as 
a Federal Advisory Committee and develops consensus-based 
recommendations on contemporary aviation issues. The organization's 
recommendations are often used as the basis for government and 
private sector decisions as well as the foundation for many TSOs.
---------------------------------------------------------------------------

    After RTCA issued its updates in December 2006, the FAA 
subsequently issued TSO-C166a, which adopted the recent modifications 
specified in change 2 to RTCA/DO-260A, and characterizes the parameters 
of NIC, NAC, and SIL.\15\ There are some aircraft equipped today with 
legacy 1090ES ADS-B systems. Operators of these aircraft would need to 
modify their broadcast link equipment to meet the proposed requirements 
defined in TSO-C166a. This modification could include hardware, 
software, or both depending upon other avionics installed on the 
aircraft.
---------------------------------------------------------------------------

    \15\ TSO-C166a superseded TSO-C166.
---------------------------------------------------------------------------

    The transition to TSO-C166a and TSO-C154b has been identified as a 
requirement for use of ADS-B in the required airspace. The United 
States faces unique challenges in air traffic control due to its high 
density airspace and stringent safety requirements. In order to 
maintain safety and capacity, given a state of increased air traffic, 
advanced surveillance technologies will be necessary. The earlier 
standards in RTCA/DO-260 do not provide the performance standards 
necessary to meet the requirements of the NAS. RTCA/DO-260a provides a 
means to transmit the Secondary Surveillance Radar beacon codes that 
currently service the NAS and will continue to be required as a backup 
to ADS-B. RTCA/DO-260 does not provide that compatibility.
    The International Civil Aviation Organization (ICAO) is in the 
process of updating the 1090ES Standards and Recommended Practices 
(SARPs) published in ICAO Annex 10, Amendment 77, to include those 
requirements identified in the publication of RTCA/DO-260A, Change 2. 
These updated SARPs are expected to become effective in November 2007.
    Operators may, under this proposal, also choose to equip with dual 
link avionics, i.e. 1090ES and UAT, which would provide the capability 
to transmit and receive information on both broadcast links at the same 
time.
    If an aircraft is to operate at or above FL240, which is discussed 
further in section IV.b.3. of this preamble (``Broadcast Link 
Requirements for Different Flight Levels''), the aircraft's broadcast 
link capabilities would have to meet the minimum performance 
requirements of TSO-C166a, (i.e., be equipped with 1090ES). 
Consequently, those aircraft operating at or above FL240 with Mode A/C 
transponders would need new transponders. Aircraft with Mode S 
transponders without compatible extended squitter capability installed 
would need to be reequipped with those providing 1090ES functionality, 
or supplement them with 1090ES to operate at or above FL240.
    In December 2006, RTCA also issued RTCA/DO-282A, Change 1 for UAT, 
which clarified the definitions of the NIC, NAC, and SIL similar to 
those specified for 1090ES discussed above. TSO-C154b adopted the 
requirements of RTCA/DO-282A and clarifies performance parameters 
capable of ensuring interoperability with ground stations deployed to 
support the Capstone program in Alaska, and to provide for future NAS 
interoperability assurances. Aircraft equipped with UAT must meet the 
minimum performance standards in TSO-C154b, or later version. There are 
very few aircraft equipped with legacy UAT equipment. Operators of 
those aircraft would need to modify their equipment to meet the 
performance standards of TSO-C154b.
2. Broadcast Link Requirements for Different Flight Levels
    The FAA proposes to require that aircraft flying at or above FL240 
have ADS-B Out performance capability using the 1090ES broadcast link. 
For operations below FL240, operators could equip their aircraft with 
either the 1090ES or UAT broadcast links. Some general aviation 
aircraft are already equipped with the UAT broadcast link, and most 
general aviation operators are expected to equip with UAT under this 
proposal in order to have TIS-B and FIS-B services. Larger aircraft, 
particularly the transport category aircraft, generally operate at 
higher altitudes and are already equipped with 1090ES that meets TSO-
C166 (which would require modification to upgrade to TSO-C166a under 
this proposal) or have equipment installed that uses the 1090 broadcast 
link. Furthermore, the international aviation communities, and for the 
most part, foreign-flag aircraft operating in the U.S., tend to operate 
large transport category aircraft that also operate at the higher 
altitudes. Having a single broadcast link at higher altitudes would 
enable aircraft equipped for ADS-B In to benefit from potential future 
applications such as aircraft merging and spacing, and self-separation. 
These applications are enabled by having aircraft identify each other 
on the same data link without the need to employ ADS-R, which would 
increase the latency of the transmission. The FAA believes that the 
approach articulated in the proposal to require 1090ES for operations 
at and above FL240 is largely consistent with how those affected 
operators would choose their respective broadcast link. While this NPRM 
does not require equipage for ADS-B In, we fully recognize that 
operators may choose to equip for that capability and that it is 
reasonable to lay the foundation so that operators may be able to take 
advantage of future applications if they so choose.
3. Part 91 Appendix H--Broadcast Message Elements
    The FAA is proposing to add an appendix to 14 CFR part 91 to 
specify the broadcast message elements necessary for ADS-B Out. These 
message elements contain the data necessary for ATC to support aircraft

[[Page 56954]]

surveillance by ADS-B. The message elements required support future 
NextGen air-to-air applications such as reduced horizontal separation 
and self separation. These message elements also support the capability 
for aircraft avionics to be verified during normal operations for 
continuing airworthiness in lieu of conducting ground checks of the 
avionics. We believe the message elements allow for further NextGen 
capabilities, at least to the extent we can predict those future needs 
at this time. However, in the future, additional elements such as 
predictive aircraft movement could be added to enable further 
capabilities.
    These elements would be broadcast automatically from the aircraft 
except where pilot entry is necessary. Pilot entry would be necessary 
for elements (g) through (k). The following is a description of each 
message element.
    (a) The length and width of the aircraft. This message element 
would provide ATC with quick reference to the aircraft's dimensions. On 
airport surfaces in particular, aircraft are in close proximity to each 
other and this information would facilitate ATC's ability to use the 
most appropriate landing and surface movement procedures for individual 
aircraft in managing traffic on the airport surfaces. This information 
would be pre-set when avionics equipment meeting the standards in TSO-
C166a or TSO-C154b, as applicable, is installed on the aircraft.
    (b) An indication of the aircraft's lateral and longitudinal 
position. This message element is derived from the aircraft's 
navigation position sensor \16\ and would provide an accurate position 
based on latitude, longitude, and accuracy values for the display of 
information in a format that meets ATC requirements. This information 
is critical to the safe and efficient separation of aircraft.
---------------------------------------------------------------------------

    \16\ The aircraft's navigation position sensor is discussed in 
detail in section IV.4. of this preamble.
---------------------------------------------------------------------------

    (c) An indication of the aircraft's barometric pressure altitude. 
This message element would provide ATC with the aircraft's altitude 
information. Currently, Sec.  91.217 requires Mode C and Mode S 
transponders to transmit pressure altitude. It is critical that the 
altitude transmitted by the Mode C and Mode S transponders is identical 
to that in the ADS-B transmission. Therefore, in addition to this 
proposed data element, we believe that Sec.  91.217 should be amended 
as well. Section 91.217 requires Mode C and Mode S transponders to 
transmit pressure altitude. We propose to revise Sec.  91.217 to also 
apply to the ADS-B transmission of altitude to ensure that the reported 
altitude from various avionics is consistent.
    (d) An indication of the aircraft's velocity. This message element 
is also derived from the aircraft's navigation position sensor and 
would provide ATC with the aircraft's airspeed with a clearly stated 
direction and describes the rate at which an aircraft changes its 
position.
    (e) An indication if TCAS II or ACAS is installed and operating in 
a mode that may generate resolution advisory alerts. This information 
would identify to ATC whether an aircraft is equipped with TCAS II or a 
later version or its European equivalent ACAS, and whether that 
equipment is operating in a mode that may generate resolution advisory 
alerts.
    (f) For aircraft with an operable TCAS II or ACAS, an indication if 
a resolution advisory is in progress. Both TCAS II and ACAS improve 
safety by detecting impending airborne collisions or incursions and 
issuing commands to the pilot on how to avoid the hazard by climbing or 
descending. If two aircraft get too close to each other, the aircrafts' 
TCAS II or ACAS systems will provide a resolution advisory (RA), which 
gives the pilots a command to climb or descend to avoid the other 
aircraft. The RA command is provided independent of ATC instructions. 
It is critical for ATC to know why an aircraft is climbing or 
descending, i.e., responding to an RA, ATC instruction, or a previous 
flight plan path. ATC may respond more efficiently and safely in 
managing the air traffic environment by knowing whether an aircraft is 
responding to an RA.
    (g) An indication if ATC services are requested. (Requires flight 
crew entry.) This message element would identify to air traffic 
controllers if services are requested and whether the aircraft is in 
fact receiving ATC services.
    (h) An indication of the Mode 3/A transponder code specified by 
ATC. (Requires flight crew entry.) All transponder-equipped aircraft on 
Instrument Flight Rules (IFR) flights are directed by ATC to ``squawk'' 
a unique four-digit code, commonly referred to as a ``Mode 3/A 
transponder code.'' All transponder equipped aircraft on Visual Flight 
Rules (VFR) flights are directed by ATC to squawk 1200. The assigned 
Mode 3/A transponder code is used by ATC to identify each aircraft 
operating under IFR, and the 1200 transponder code identifies aircraft 
operating under VFR.
    An aircraft equipped with ADS-B Out continually broadcasts its 
state vector (3-dimensional position and 3-dimensional velocity). It is 
critical for ATC to correlate and verify that the ADS-B Out information 
transmitted from each aircraft is displayed and identified correctly on 
the ATC radar display. Therefore, it is imperative that the ATC-
assigned transponder code be identical to the assigned transponder code 
in the ADS-B Out message. If the aircraft's avionics are not capable of 
allowing a single point of entry for the transponder and ADS-B Out Mode 
3A code, the pilot would have to ensure that conflicting codes are not 
transmitted to ATC. Operational procedures would have to be developed, 
including specific guidance, instructions, or training material 
provided by the equipment manufacturer, as well as the operator 
training programs, manuals, Operations Specifications, and Letters of 
Authorization, to ensure that conflicting codes are not transmitted to 
ATC.
    (i) An indication of the aircraft's call sign that is submitted on 
the flight plan, or the aircraft's registration number. (Aircraft call 
sign requires flight crew entry.) This message element would correlate 
flight plan information with the data that ATC views on the radar 
display and facilitate ATC communication with the aircraft. The 
aircraft's call sign or registration number broadcast in the ADS-B 
message would have to be identical to information contained in its 
flight plan.
    (j) An indication if the flight crew has identified an emergency, 
and if so, the emergency status being transmitted. (Requires flight 
crew entry.) This message element would alert ATC that the aircraft is 
experiencing emergency conditions and indicate the type of emergency. 
Applicable emergency codes would be found in the Aeronautical 
Information Manual. This information would alert ATC to potential 
danger to the aircraft so it could take appropriate action.
    (k) An indication of the aircraft's ``IDENT'' to ATC. (Requires 
flight crew entry.) ATC may request an aircraft to ``IDENT,'' to aid 
controllers to quickly identify a specific aircraft. The pilot manually 
inputs the aircraft's identity, which then highlights the aircraft on 
the ATC scope. When activated, this message element allows 
identification of the aircraft with which ATC is in communication.
    (l) An indication of the aircraft's assigned ICAO 24-bit address. 
ICAO 24-bit codes are unique and assigned to each individual aircraft. 
These codes are necessary for aircraft used for international 
operations. This code would provide the FAA with the future capability 
to identify aircraft using the

[[Page 56955]]

ICAO 24-bit address. This capability addresses limits on future 
capacity due to the finite number of aircraft that can be tracked with 
discrete transponder codes.
    (m) An indication of the emitter category. If ATC knows the emitter 
category, it can determine separation minima based in part on a 
particular aircraft's wake vortex. This information would be used to 
provide air traffic controllers and ground crews with more efficient 
information regarding a particular aircraft's constraints and 
capabilities. Once the emitter category is set at installation, it 
would not change. (Refer to TSO-C166a or TSO-C154b for additional 
information.) Some examples of emitter categories to be used (as 
specified in RTCA DO-260A, DO-242A, and DO-282A) include, but are not 
limited to, the following:
    <bullet> Light (ICAO)--7,000 kg (15,500 lbs) or less.
    <bullet> Small aircraft--7,000 kg to 34,000 kg (15,500 lbs to 
75,000 lbs).
    <bullet> Large aircraft--34,000 kg to 136,000 kg (75,000 lbs to 
300,00 lbs).
    <bullet> High vortex large (i.e., B-757).
    <bullet> Heavy aircraft (ICAO)--136,000 kg (300,000 lbs) or more.
    <bullet> Rotorcraft.
    (n) An indication whether a cockpit display of traffic information 
(CDTI) is installed and operable. This message element would alert ATC 
as to whether an aircraft has an operable CDTI \17\ installed. A CDTI 
is necessary for aircraft to have ADS-B In capability. This message 
element would indicate to ATC which aircraft are capable of receiving 
ADS-B In services.
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    \17\ CDTI is the function of presenting surveillance traffic 
information (e.g., airborne or surface) to the flight crew. To 
display traffic, the CDTI may use a dedicated display or a shared 
multi-function display (MFD) device. The CDTI is capable of 
displaying position information for nearby aircraft and ADS-B-
equipped airport surface vehicles. The CDTI consolidates ADS-B 
traffic targets, terrain, weather, and other products relative to 
the pilot's own aircraft or flight operation. It allows pilots to 
display textual and graphical information provided by the ADS-B 
System and Broadcast Services.
---------------------------------------------------------------------------

    (o) An indication of the aircraft's geometric altitude. The 
geometric altitude is a measure of altitude provided by a satellite-
based position service, determined mathematically, based on a three-
dimensional position in space. This message element is necessary to 
confirm accuracy or discrepancies between geometric and barometric 
altitude, which changes as a function of air pressure in the 
environment. The message element would serve as a tool for validating 
positioning services.
4. Navigation Position Sensor and the Accuracy and Integrity of the 
ADS-B Message
    ADS-B Out continuously transmits aircraft information through the 
selected broadcast data links of 1090ES or UAT. The aircraft's lateral 
and longitudinal position and velocity are proposed data elements 
transmitted in the broadcast message. The navigation position sensor is 
equipment onboard the aircraft that computes a geodetic position 
(latitude and longitude) that can be a separate sensor or integrated 
into other navigation equipment or system onboard the aircraft. 
(Examples of such equipment are LORAN C, GPS, GPS-WAAS, DME/DME and 
Inertial Reference Unit (IRU).)
    The accuracy and integrity of these broadcast message elements 
transmitted from the aircraft to the ground stations depends on the 
aircraft's navigation position sensor and the signal source from which 
the position is derived. The accuracy and integrity of the transmitted 
aircraft position and velocity are critical for use in surveillance and 
various airborne and surface applications. The accuracy and integrity 
of transmitted information expressed by ADS-B avionics is measured by 
the Navigation Accuracy Category for Position (NACp), the Navigation 
Accuracy Category for Velocity (NACv), the NIC and the SIL.
    An aircraft transmitting its position and velocity with the 
accuracy and integrity proposed in part 91, Appendix H, Section 3 (ADS-
B Out Performance Requirements for NIC, NAC, and SIL) would be more 
accurately identified by ATC than it would be in today's radar 
environment. The confidence with respect to the accuracy of the 
position and velocity reported by ADS-B Out would enable the future 
applications discussed further in this proposal that simply could not 
be provided by existing surveillance systems. While existing 
surveillance systems provide information that is sufficient for 
separation purposes and the capacity needs of today's traffic 
environment, a more responsive and versatile ATC system will need 
improved accuracy and integrity of broadcast information for future 
surveillance performance. The values proposed would ensure that the 
information ATC receives has the level of performance and the requisite 
confidence in the accuracy of that information necessary to control 
aircraft. Increasing the quality and standards for surveillance 
information presents new opportunities for efficiency and capacity 
improvements in the NAS, and the potential for future self-separation 
or air-to-air applications of ADS-B.
    The NACp specifies the accuracy of the aircraft's horizontal 
position information (latitude and longitude) and the vertical 
geometric position transmitted from the aircraft's avionics. All 
aircraft position information has a margin of error and the accuracy 
category specifies that margin. The NACp specifies with 95 percent 
probability that the reported information is correct within an 
associated allowance. (The horizontal 95% bound error allowance 
resembles an imaginary circle around the aircraft with a radius 
equivalent to the NACp defined value.) ATC and aircraft equipped for 
ADS-B In would monitor the NACp reporting to ensure that the accuracy 
supports the intended operational use. Not all navigation position 
sensors are capable of providing the necessary aircraft information 
with the accuracy and integrity needed to support certain surveillance 
applications.\18\ In order to use ADS-B Out for surveillance and 
separation, the NACp value must have a small margin of error in 
position reporting.
---------------------------------------------------------------------------

    \18\ Surveillance applications are discussed further in Section 
V of this NPRM.
---------------------------------------------------------------------------

    In today's radar surveillance environment, aircraft position 
accuracy is required to be within 0.3 NM for operations in the en route 
airspace, and 0.1 NM for operations within terminal area airspace. An 
aircraft broadcasting its position with a NACp equal to or greater than 
7 would provide a horizontal position accuracy of at least 0.1 NM with 
no specific requirement for vertical (geometric) position accuracy. 
Aircraft position reported at a NACp equal to or greater than 7 would 
meet the minimum radar accuracy requirement for terminal area 
operations and exceed radar performance for en route operations. 
Therefore, the FAA believes that the minimum accuracy requirement 
necessary to maintain an equivalent level of surveillance in the 
terminal airspace area (and provide for equivalent separation as that 
in today's radar environment) would be a NACp of 7. The FAA is not, 
however, engaging in this rulemaking simply to meet the level of 
surveillance that exists in the current infrastructure, or to establish 
a new surveillance system that would only enable separation performance 
equivalent to that realized today. ADS-B performance is intended to go 
beyond today's standards for accuracy and provide a platform for 
NextGen. In order to accomplish that goal, we propose a minimum 
accuracy value of NACp 9 in

[[Page 56956]]

all airspace areas that ADS-B would be required. This proposed accuracy 
requirement would provide horizontal position information for ADS-B Out 
equipped aircraft to within 30 meters (0.016NM) horizontally and 
vertical (geometric) position accuracy to within 45 meters. This 
proposed accuracy requirement could make it possible for future 
airspace separation to be reduced from today's current separation 
minima. At this time the FAA cannot determine the extent to which 
separation standards might be reduced. Significant testing and 
certification is required before any reduction in separation standards 
might be applied. The FAA may examine the possible reduction of 
separation standards once ADS-B has been certified to meet existing 
separation standards safely and consistently.
    Under this proposal, any aircraft not operating with at least this 
level of performance would not be permitted in the designated airspace 
without first obtaining authorization from ATC. If the aircraft 
broadcast message element for position has an NACp of less than 9, ATC 
would be notified and it could choose to revert to a backup system or 
apply procedural mitigation.
    This proposed NACp of 9 would also provide the necessary accuracy 
to enable certain applications on the surface at the nation's busiest 
airports. For various operational applications including situational 
awareness and traffic alerting, it would be necessary for aircraft 
position accuracy to be transmitted with an error of 30 meters or less 
horizontally, particularly for surface operations. The proposed 
requirement for an NACp equal to or better than 9 would meet the 30 
meter or less performance requirement for surface operations and would 
apply to all aircraft equipped with ADS-B Out. If the aircraft 
broadcast message element for position has an NACp of less than 9, ATC 
and aircraft equipped with ADS-B In would be automatically notified 
that the ADS-B Out performance for a particular aircraft is degraded 
and therefore, the information is unusable to support either 
situational awareness on the surface or awareness of runway occupancy 
on approach to airports. The NACp values are specified in greater 
detail in RTCA/DO-260A and RTCA/DO-282A, which are recognized 
performance standards by the applicable TSOs identified under this 
proposal.
    The NACv is a measured value similar to the NACp value except that 
it applies to the computed velocity derived from navigation position 
sensor or navigation system. In accordance with TSO-C166a and TSO-
C154b, which recognize the performance standards of DO-260A and DO-282A 
respectively, the NACv must be greater than or equal to 1. This means 
that the estimate of aircraft velocity must be accurate to within 10 
meters per second and must be reported with 95 percent probability.
    NIC differs from NAC in that a NIC value specifies aircraft 
integrity containment often referred to as the ``containment radius,'' 
which is the maximum error for the broadcast position as described in 
RTCA/DO-260A, Change 2 and DO-282A, Change 1. NIC and NAC performance 
values will vary depending upon the positioning service and navigation 
position sensor. NIC/NAC values may be enhanced or degraded by external 
NAS infrastructure or by characteristics of avionics systems 
performance. For instance, a GPS outage would interrupt the integrity 
and accuracy of the broadcast information. Avionics failures also could 
degrade expected performance. The NIC value is broadcast so that 
surveillance services may determine whether the horizontal and vertical 
(geometric) position meets an acceptable level of integrity containment 
for the intended operation or phase of flight. For ADS-B Out, the FAA 
proposes a NIC value of 7. This value would bound the error to within 
0.2 NM. The NIC parameter combined with the SIL parameter described in 
the next paragraph provides integrity assurance in broadcast position.
    The SIL specifies the ADS-B Out avionics integrity level and the 
probability that the position error may be larger than the reported 
NIC. The SIL may be configured at the time of installation. SIL is 
typically based on the design assurance level \19\ of the ADS-B Out 
avionics and its navigation position sensor. While a NIC value varies 
based on computed navigation sensor position, SIL is typically a static 
(unchanging) value for the ADS-B Out avionics. For example, while the 
NIC is dependent on the satellite constellation (or number of available 
satellites), the SIL's reporting of the installed ADS-B avionics is not 
dependent upon the satellite constellation and would not be affected by 
changes in the number of available satellites being used in the derived 
position. To achieve performance at least equivalent to existing radar 
systems, the FAA proposes a SIL of 2 or better. This value would 
provide integrity assurance that meets a failure rate probability of 
99.999 per flight hour.
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    \19\ ADS-B Out avionics design assurance is dependent on both 
the hardware and software levels. There are 5 hardware design 
assurance failure classifications; (1) Catastrophic, (2) Hazardous/
Severe-Major, (3) Major, (4) Minor, and (5) No Safety Effect. RTCA/
DO-178B ``Software Considerations in Airborne Systems and Equipment 
Certification'' software classifications are; (1) Level A, (2) Level 
B, (3) Level C, (4) Level D, and (5) Level E which directly map to 
the hardware design assurance failure classifications. The minimum 
requirement for systems development assurance for ADS-B Out is a 
hardware design assurance (failure classification) of ``major'' 
dependent upon RTCA/DO-178B Level ``C'' software.
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    The proposed NIC, NACp, NACv, and SIL requirements would support 
not only ATC services, but also advisory applications for those who 
choose to equip aircraft with ADS-B In. The proposed values for 
accuracy and integrity would meet the needs of all the ADS-B In 
applications discussed in this proposal. Terminal area and surface 
applications such as Final Approach and Runway Occupancy Awareness 
would not be enabled unless all aircraft in the surface environment 
report their position accurately on runways and taxiways (NACp equal to 
or greater than 9). Universal compliance with accuracy and integrity 
requirements would ensure that ADS-B In applications could provide 
accurate data even in a closely spaced environment such as an airport 
surface.
    This proposal specifies performance standards for aircraft avionics 
equipment for operation to enable ADS-B Out. These performance 
standards would accommodate and facilitate the use of new technology. 
Presently, GPS augmented by the Wide Area Augmentation System (WAAS) is 
the only navigation position service that provides the level of 
accuracy and integrity (NIC, NACp, and NACv) to enable ADS-B Out to be 
used for NAS-based surveillance operations with sufficient 
availability. The FAA is considering whether other navigation position 
systems such as the Global Navigation Satellite System (GNSS) combined 
with tightly coupled inertial navigation systems are also capable of 
meeting the proposed performance standards. Other types of positioning 
systems that meet the requisite performance requirements may be 
developed in the future, and may include satellite constellations 
similar to the Galileo system, or tightly coupled IRU to existing GPS. 
At this point, however, the agency is still studying the ability of 
these other navigation position systems to meet the performance 
standards articulated in this proposal.
    In order to meet the proposed performance requirements using the 
GPS/WAAS system, aircraft would be required to have equipment installed 
onboard the aircraft that meets one of the following: (1) TSO-C145b, 
Airborne Navigation Sensors using the GPS augmented by WAAS; or (2) 
TSO-C146b Stand-Alone Airborne Navigation

[[Page 56957]]

Equipment using the GPS augmented by WAAS.
5. ADS-B Aircraft Antenna Diversity and Transmit Power Requirements
    The aircraft antenna is an important part of the overall ADS-B Out 
system because antennas are major contributors to the system link 
performance. The location, number of antennas and transmit power 
required for the airborne ADS-B Out system is a function of the 
equipment class for the selected broadcast link (UAT or 1090ES). This 
proposal specifies the classes of 1090ES and UAT equipment that would 
meet the performance standards for ADS-B Out. The equipment classes 
include requirements for aircraft antenna diversity and transmit power, 
as explained below.
    Optimal link performance requires both a top and bottom antenna 
(antenna diversity). Accordingly, the agency is proposing to require 
that the aircraft be equipped with both a top and bottom antenna to 
support ADS-B Out applications as well as future air-to-air ADS-B In 
applications. Antenna diversity is a requirement of the equipment 
classes identified in the proposed rule.
    For aircraft already equipped with a Mode S transponder (TSO-C112), 
which incorporates antenna diversity, no additional antennas would be 
required for ADS-B Out using 1090ES. For ADS-B In, however, additional 
1090 MHz receive antennas may be necessary depending on the additional 
avionics equipment installed on the aircraft. It may be possible to 
share the TCAS 1090 MHz receiver, as long as it can be shown that TCAS 
performance is not degraded. This shared approach is addressed in TSO-
C166a.
    For ADS-B installations using UAT, it may be possible to share the 
aircraft's existing bottom ATCRBS transponder (TSO-C74c) antenna 
through the use of an antenna diplexer, thus only requiring 
installation of a top antenna. Specifications for the diplexer are 
addressed in TSO-C154b. This dual antenna system would not result in 
degraded performance relative to that which would have been produced by 
a single system having a bottom-mounted antenna.
    Antennas would also have to transmit their signal at a certain 
level of power in order to ensure that transmitted signals are received 
by ground stations, and by ADS-B In equipped aircraft and vehicles. The 
UAT requires a 16 watt minimum transmit power. Therefore, aircraft 
equipped with the UAT would be required to have Class A1H, A2, A3, or 
B1 equipment, as defined in TSO-C154b. The 1090ES broadcast link 
requires a 125 watt minimum transmit power. Correspondingly, aircraft 
operating with 1090ES would also be required to have Class A1, A2, A3 
or B1 equipment, as defined in TSO-C166a. The transmitted power level 
supports the coverage requirements for each equipment class, including 
the impact of loss of antenna system performance.
    These proposed antenna requirements are necessary so that receivers 
of the ADS-B system on the ground and in other aircraft could receive 
ADS-B Out messages with sufficient strength, consistency, and update 
rate to provide the necessary information for surveillance and 
broadcast services.
6. Latency of the ADS-B Out Broadcast Message Elements
    This proposal defines the latency for the ADS-B message from the 
time information enters the aircraft through the aircraft antenna(s) 
until the time it is transmitted from the aircraft. A specific limit 
between the time the information is received and then processed through 
onboard avionics is necessary to ensure timely transmission of 
information and to realize the benefits of the ADS-B system. As 
discussed previously, ADS-B Out transmits accurate and timely 
information more frequently than information transmitted under the 
current radar surveillance system. With ADS-B, information is sent to 
the aircraft from satellites, processed on the aircraft and sent to 
ground stations. The information would enter the aircraft through an 
antenna(s), be processed by the onboard avionics (e.g., navigation 
sensor, navigation processor, and either 1090ES or UAT broadcast 
links), then transmitted to the ground stations through another 
antenna(s) on either the 1090 or 978 MHz frequencies, depending upon 
the aircraft's avionics.
    Under this proposal, the navigation sensor would process 
information received by the aircraft's antenna(s) and forward this 
information to the ADS-B broadcast link avionics in less than 0.5 
seconds. That processed information would then be transmitted in the 
ADS-B message from the ADS-B Out broadcast link avionics in less than 
1.0 second from the time it was received from the navigation sensor. 
This latency would support the proposed requirement that the aircraft 
transmit its position and velocity at least once per second while 
airborne, or while the aircraft is moving on the surface. Additionally, 
the aircraft would be required to transmit its position information at 
least once every 5 seconds while stationary on the airport surface.
    Latency requirements for the reception and processing of ADS-B Out 
by the ground station for display to the ATC automation system are 
described in the FAA surveillance and broadcast services acquisition 
documents.\20\
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    \20\ Final Program Requirements for Surveillance and Broadcast 
Services, En Route and Oceanic Services, Air Traffic Organization, 
Federal Aviation Administration.
---------------------------------------------------------------------------

7. Maintenance
    This NPRM would not require additional maintenance requirements for 
the installation of ADS-B avionics equipment. The current requirements 
of 14 CFR 21.50, ``Instructions for continued airworthiness and 
manufacturer's maintenance manuals having airworthiness limitations 
sections,'' are applicable to all ADS-B equipment. Since any alteration 
of equipment is subject to the requirements of that section, the 
existing requirements would apply to any new avionics equipment 
installed in an aircraft.

C. Operational Procedures

1. Applicability
    With specific and limited exceptions, the ADS-B Out performance 
requirements proposed here would apply to all aircraft operating in 
certain U.S. designated airspace.\21\ These requirements would be 
applicable to operations conducted by domestic and foreign operators in 
U.S. territorial airspace. The efficiency and capacity benefits that 
can be realized with ADS-B Out are largely obtainable if all aircraft 
are equipped for ADS-B Out broadcast. There are some aircraft, however, 
that were not originally certified with an electrical system, or that 
have not been subsequently certified with such a system installed, for 
which installation of equipment that meets ADS-B Out performance 
standards is impractical. These aircraft may include certain airplanes, 
balloons, and gliders. There may be instances where a pilot of an 
aircraft without an electrical system (such as a glider) may want to 
operate in airspace where ADS-B Out performance standards would be 
required under this proposal. The procedures for requesting 
authorization to enter the airspace where ADS-B is required would be 
the same procedures used today for aircraft not equipped with a 
transponder to enter certain airspace. In these cases, an operator may 
request an ATC authorization to operate

[[Page 56958]]

in the airspace and the FAA addresses those requests on a case-by-case 
basis. In formulating this proposal, the FAA considered various options 
including whether to require ADS-B Out performance standards for 
aircraft based on the type of operation conducted (e.g., part 121 and 
135 operations), or based on the type of aircraft (e.g., large or 
small). The agency concluded that there is no distinguishing 
operational need for differing performance standards based on aircraft 
type or category of the operation, as many different types of operators 
and aircraft operate in the same airspace.
---------------------------------------------------------------------------

    \21\ See section IV.c.2. for a further discussion of the 
airspace where ADS-B Out would be required.
---------------------------------------------------------------------------

    The FAA also considered proposing ADS-B Out performance standards 
for aircraft operations at and above specified altitudes. Since 
aircraft operate at various altitudes between the en route and terminal 
environments, this option was dismissed as confusing to pilots and 
impractical to implement. ADS-B requirements based on specific 
altitudes could result in different equipment requirements applying 
within different segments of the same class of airspace.
    Lastly, the FAA considered whether to propose ADS-B Out for all 
aircraft operations in domestic airspace (Classes A-G). Domestic 
airspace includes airspace over the territorial United States that 
extends out to 12 NM from the coastline that is controlled by ATC 
(Classes A, B, C, D, and E) and uncontrolled airspace (Classes G). 
While this would result in almost 100% of aircraft meeting ADS-B Out 
performance requirements and increase the number of identifiable 
aircraft in the NAS, it also would place an unnecessary financial and 
operational burden on aircraft operators who do not operate in 
controlled airspace, or who are not under ATC surveillance.
2. Airspace
    In February 1988, the FAA promulgated an ATC transponder and 
altitude reporting equipment final rule, which established Sec.  91.215 
of 14 CFR and articulated the operating requirements for ATC 
transponder and altitude reporting equipment and use.\22\ The rule 
specifies the airspace for which Mode A/C, and S transponders are 
required, and the process for when an operator may request a deviation 
from the transponder requirements. Under Sec.  91.215, transponders are 
required for all aircraft operating in Classes A, B, and C airspace 
areas, and in all airspace at and above 10,000 feet MSL over the 48 
contiguous United States and the District of Columbia. In addition, 
transponders are required for operations within 30 NM of an airport 
listed in 14 CFR part 91, Appendix D, from the surface upwards to 
10,000 feet MSL. (The airports listed in Appendix D are in Class B 
airspace areas.) \23\
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    \22\ Transponder with Automatic Altitude Reporting Capability 
Requirement, 53 FR 4306; February 12, 1988.
    \23\ This section excludes from the transponder requirements all 
aircraft not originally certificated with an electrical system or 
not subsequently certified with such a system installed, such as 
balloons or gliders. These operations may be conducted in the 
airspace within 30 nautical miles of an airport listed in part 91 
appendix D provided that the operations are conducted: (1) Outside 
any Class A, Class B, or Class C airspace area; and (2) below the 
altitude of the ceiling of a Class B or Class C airspace area 
designated for any airport or 10,000 feet MSL, whichever is lower.
---------------------------------------------------------------------------

    ADS-B Out would provide for enhanced surveillance in areas where 
SSR surveillance currently exists. Consequently, the FAA believes that 
it is reasonable to require that aircraft meet the performance 
requirements necessary for ADS-B Out for operation in airspace that 
currently requires transponders. Similar to Sec.  91.215, proposed 
Sec.  91.225 would require that aircraft meet ADS-B Out performance 
requirements to operate in Class A, Class B, and Class C airspace 
areas, and in Class E airspace areas at and above 10,000 ft MSL over 
the 48 contiguous United States and the District of Columbia. In 
addition, this proposal would require that aircraft meet ADS-B Out 
performance requirements to operate in Class E airspace over the Gulf 
of Mexico, from the coastline of the United States out to 12 NM at and 
above 3,000 feet MSL. Similar to the transponder requirements, ADS-B 
Out also would be required within 30 NM of an airport listed in 14 CFR 
part 91, appendix D, from the surface upward to 10,000 feet MSL.
    This proposal would permit aircraft not originally certificated 
with an electrical system or not subsequently certified with such a 
system installed (such as a balloon or glider) to conduct operations 
without ADS-B Out in the airspace within 30 NM of an airport listed in 
part 91 appendix D if the operations are conducted: (1) Outside any 
Class B or Class C airspace area; and (2) below the altitude of the 
ceiling of a Class B or Class C airspace area designated for an airport 
or 10,000 feet MSL, whichever is lower.
    Generally, Class A airspace is that airspace from 18,000 feet MSL 
to and including FL 600, including the airspace overlying the waters 
within 12 NM of the coastline of the United States. This proposal would 
not require aircraft to meet the proposed ADS-B Out performance 
standards for aircraft that operate in Class A airspace that extends 
beyond 12 NM from the U.S. coastline and that do not enter U.S. 
territorial airspace.\24\
---------------------------------------------------------------------------

    \24\ There are numerous Offshore Airspace Areas that are 
designated as Class A airspace and the boundaries of those airspace 
areas extend beyond 12 NM from the coastline of the U.S. into 
international waters. Under agreement with ICAO, the U.S. provides 
ATC services in these areas and may designate the airspace 
accordingly in order to indicate to pilots the type of ATC services 
that may be provided.
---------------------------------------------------------------------------

    Class B airspace is designated from the surface to 10,000 feet MSL 
surrounding the nation's busiest airports in terms of airport 
operations or passenger enplanements. (Class B airspace areas generally 
are configured and appear as an upside down wedding cake.) The 
configuration of each Class B airspace area is individually tailored 
and consists of a surface area and two or more layers, and is designed 
to contain all published instrument procedures. An ATC clearance is 
required for all aircraft to operate in the area, and all aircraft that 
are cleared receive separation services within the airspace. Under this 
proposal, ADS-B Out would be required for aircraft operating in Class B 
airspace areas. In addition, for those airports listed in part 91 
appendix D, ADS-B Out would be required for operations within 30 NM of 
the airport from the surface up to 10,000 feet MSL. This area can 
experience a high volume of aircraft operations and complex transitions 
from the en route environment to the terminal area around the nation's 
busiest airports. Consequently, we expect ADS-B Out to result in better 
surveillance across a larger area, leading to better ATC situational 
awareness.
    Generally, Class C airspace is designated from the surface to 4,000 
feet above the airport elevation surrounding those airports that have 
an operational control tower, are serviced by a radar approach control, 
and have a certain number of IFR operations or passenger enplanements. 
Although the configuration of each Class C area is individually 
tailored, the airspace usually consists of a surface area with a 5 NM 
radius and an outer circle within a 10 NM radius that extends from no 
lower than 1,200 feet up to 4,000 feet above the airport elevation. 
Each person must establish two-way radio communications with the ATC 
facility providing air traffic services prior to entering the airspace 
and must thereafter maintain those communications while within the 
airspace.
    Similar to the transponder requirements, we are proposing that all

[[Page 56959]]

aircraft in Class E airspace of the 48 contiguous United States and the 
District of Columbia, at and above 10,000 feet MSL, meet ADS-B Out 
performance requirements.
    Additionally, the FAA proposes that aircraft operating in Class E 
airspace over the Gulf of Mexico, from the coastline of the United 
States out to 12 NM at and above 3,000 feet MSL, meet the performance 
requirements for ADS-B Out. The proposed 3,000 feet MSL will be the 
lowest altitude that surveillance and communication coverage will exist 
for the purposes of ATC services. The rule is restricted to 12 NM from 
the coastline, which is the extent of the NAS in that area.
    This proposal includes an option for pilots to request an 
authorization from ATC to operate in certain designated airspace with 
aircraft that do not meet the ADS-B Out performance standards. As 
stated previously, aircraft that do not have an electrical system, and 
therefore are not ADS-B Out compliant, may receive an ATC authorization 
to operate in the designated airspace. This provision would provide ATC 
with the flexibility to control aircraft that may have been directed to 
turn off ADS-B or to reroute non-equipped aircraft through a regulated 
area if that is necessary for safety.\25\
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    \25\ If the Air Traffic Controller identifies that the aircraft 
avionics is not operating properly (such as providing erroneous or 
incomplete information), the pilot would be instructed to turn off 
the avionics. A simple switch or button in the cockpit to disable 
ADS-B avionics would provide this feature. Aircraft would then be 
controlled using the backup surveillance system or procedurally. 
This is similar to the methods used today in removing faulty 
transponder information from a controllers display. Pilots currently 
have the capability to turn off transponders. Aircraft are then 
handled procedurally or through primary radar returns.
---------------------------------------------------------------------------

    ATC authorizations may contain conditions necessary to provide a 
level of safety equivalent to operation by an aircraft equipped with 
ADS-B Out equipment. ATC may not be able to grant authorization in all 
cases.
3. Pilot Procedures
    In accordance with proper preflight actions,\26\ each operator 
would have to verify ADS-B Out availability for the flight planned 
route through the appropriate flight planning information sources. If 
the aircraft cannot meet the proposed performance requirements using a 
given position service, the operator would have to use either a 
different, available position service, re-route, or reschedule the 
flight. Under this proposal, pilot procedures are expected to be 
minimal. Pilots would have to: (1) Check that the ADS-B avionics 
equipment is turned on and operating properly; (2) ensure that message 
elements (g)-(k) of part 91, appendix H, section 4 are entered during 
the appropriate phase of flight; (3) turn off the ADS-B equipment if 
directed by ATC; and (4) if notified by ATC that the aircraft's ADS-B 
information is not being transmitted, request special handling that may 
include accommodation (on a case-by-case basis), or direction to exit 
the present airspace.
---------------------------------------------------------------------------

    \26\ See 14 CFR 91.103.
---------------------------------------------------------------------------

4. Backup Surveillance Strategy
    The FAA recognizes there are vulnerabilities in using a GPS system 
as the aircraft's position service. There are times when GPS may be 
unreliable in certain areas and during certain times due to planned 
testing or solar flare activity. Unintentional interference is 
historically infrequent in the U.S. In the event of GPS outages, a 
backup strategy is necessary for ATC to continue surveillance 
capability.
    The FAA identified and analyzed several potential backup 
strategies. The strategies varied from SSR, active and passive 
multilateration, Distance Measuring Equipment (DME)/IRU, Satellite 
Navigation (SATNAV), and combinations thereof. The FAA reviewed the 
cost estimates and performance of the various combinations and 
conducted comparative safety assessments. In May 2006, the 
Surveillance/Positioning Backup Strategy Technical Team was formed to 
review candidate strategies. The team members consisted of 
representatives from air transport, general aviation, avionics 
manufacturers, and the FAA's Aircraft Certification Service and Air 
Traffic Organization. In addition, a steering committee was organized 
under the RTCA ADS-B Working Group and the RTCA Air Traffic Management 
Advisory Committee to ensure that user needs were being addressed.
    The FAA specified that the backup strategy must meet certain 
minimum requirements to meet the needs of the airspace users. The 
strategy must be able to support ATC surveillance to at least the same 
extent as current back up surveillance capabilities. In other words, at 
least the same level of capacity must be maintained during a loss of 
GPS signal as would be experienced during a comparative loss of radar 
services today in both the terminal and en route areas over several 
days.\27\
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    \27\ Generally, a loss of radar services for a given area is 
mitigated in one of several ways: by providing terminal capabilities 
(e.g., 3 NM separations) with reduced coverage using a nearby 
terminal radar; by providing en route capabilities (e.g., 5 NM 
separations) with reduced coverage using the nearest en route radar; 
or by reversion to procedural separation if neither of the first two 
options are feasible.
---------------------------------------------------------------------------

    The FAA has concluded that a strategy of maintaining a reduced 
network of SSRs best meets the agency's back up needs given the 
limitations of ADS-B surveillance capabilities. Under this strategy, 
secondary radar services will be provided in high density terminal 
airspace (surrounding approximately the top 40 airports in terms of 
capacity), all en route airspace above 18,000 feet MSL, and medium 
density terminal airspace above certain altitudes, as determined by 
proximate en route SSR coverage (identical to today's Center Radar 
Automated Radar Terminal Systems Processing (CENRAP) coverage). This 
approach would require retaining 40 terminal SSRs and 150 en route SSRs 
beyond 2020, which is approximately one-half of the quantity in use 
today. Primary surveillance radar services will be retained in all 
terminal areas covered by primary radar today (approximately 200 
locations), to serve as the means of mitigating single aircraft 
avionics failures. No new avionics would be required to support this 
strategy. The legacy transponders (Mode A/C/S) continue to support 
secondary radar surveillance. A copy of the FAA's Surveillance/
Positioning Backup Strategy Alternatives Analysis Final Report, dated 
December 8, 2006, has been placed in the docket for this rulemaking.
    During interference outages of GNSS (scheduled or unscheduled), the 
FAA expects to revert to the backup ground-based surveillance system 
and temporarily allow operations without ADS-B Out in required 
airspace. Pilots would be notified of such action via the Notice to 
Airmen (NOTAM) system. The FAA also expects to revert to the backup 
surveillance system during significant degradation in the GPS 
constellation. When deciding to issue NOTAMs to allow operations by 
aircraft with inoperable ADS-B Out equipment, the FAA will weigh the 
impact of denying airspace access to those aircraft that do not comply 
with the performance requirements against the reduction in operational 
capability due to the limitations of the backup surveillance system.
5. Compliance Schedule for ADS-B Out Requirements
    The FAA proposes that affected aircraft meet ADS-B Out performance 
requirements by January 1, 2020. The FAA's schedule for ADS-B Out calls 
for

[[Page 56960]]

the ground infrastructure, including the provision of broadcast 
services, to be in place and available by the end of 2013 where 
surveillance exists today. The FAA is committed to meeting this 
schedule, but if unforeseen circumstances prevent ADS-B Out services 
from being available by the end of 2013 where surveillance exists 
today, the FAA would follow notice and comment rulemaking procedures to 
adjust the compliance date. Although compliance of the rule would not 
be necessary until 2020, it is necessary to have the final requirements 
published to allow avionics manufacturers time to produce compliant 
equipment. It is also preferable to give operators time to schedule 
equipment installation consistent with the aircraft's normal 
maintenance cycle. A 10-year compliance window gives the aviation 
community ample time to manage costs and minimize the impact of ADS-B 
installation on their normal operations.

V. ADS-B In

A. Avionics

    The FAA is not proposing to mandate ADS-B In performance 
requirements at this time. While ADS-B In provides substantial benefits 
to operators, it has not been identified as a requirement for 
maintaining the safety and efficiency of NAS operations at this time. 
However, this NPRM includes a discussion of ADS-B In because ADS-B Out 
transmissions provide the aircraft information viewed by the flight 
crew in aircraft equipped for ADS-B In. Operators who voluntarily equip 
with ADS-B In could receive additional benefits compared to those that 
equip only with ADS-B Out. ADS-B In provides the capability to display 
ADS-B message information to pilots in the flight deck. The ADS-B In 
function is a combination broadcast link processor (i.e., it receives 
information) and flight deck display.
    The ADS-B Out broadcast message elements support the initial ADS-B 
In applications discussed in this proposal. However, future ADS-B In 
applications may require additional broadcast message elements in the 
ADS-B Out transmission. The reason for the differences is that the 
information displayed to ATC may be a subset of information displayed 
to the pilots. Additional ADS-B Out broadcast message elements beyond 
those described in this document could be needed to support a fully 
functional ADS-B In CDTI for future operational applications. 
Additional message elements cannot be defined until future applications 
have been developed. The current set of ADS-B Out message elements will 
meet the needs of the initial services and applications and the future 
applications currently pursued by the FAA.
    As some operators may voluntarily equip with ADS-B In avionics to 
take advantage of emerging technology, the ground infrastructure will 
be designed to accommodate ADS-B Out and ADS-B In. In order to provide 
ADS-B In equipped aircraft with the capability to use the information 
transmitted, a service called ADS-R has been developed. In this 
proposal, ADS-R is considered part of the ground infrastructure that 
will need to be in place to enable a fully functional ADS-B system. 
ADS-R provides aircraft with a more complete traffic picture of other 
ADS-B equipped aircraft using a different data-link (i.e., 1090ES 
versus UAT). For example, ADS-R takes the aircraft's ADS-B information 
that is transmitted by 1090ES and ``re-broadcasts'' that information to 
any aircraft that is equipped for ADS-B In and uses UAT. ADS-R 
similarly makes the corresponding rebroadcast of information from UAT 
equipped aircraft to ADS-B In equipped aircraft using 1090ES. As stated 
previously, this proposal does not seek to require ADS-B In. The FAA 
does realize, however, that some operators may voluntarily equip with 
ADS-B In avionics to take advantage of emerging technology. The ADS-B 
ARC is investigating ways to encourage operators to equip with ADS-B 
prior to the compliance date of the rule. The FAA will review the ARC's 
recommendations on how to facilitate the transition between legacy 
surveillance and ADS-B.

B. Applications and Services

    As this proposal lays the foundation for the entire ADS-B system, 
it is appropriate to briefly discuss the applications and services that 
would be available with ADS-B In. Functions and associated applications 
that enable an aircraft to be able to receive ADS-B messages from 
ground stations and from other aircraft are collectively referred to as 
ADS-B In. If aircraft are voluntarily equipped with ADS-B In, pilots 
could see real-time information similar to what ATC views and have 
access to similar services and applications. Pilots would have better 
situational awareness because their flight deck displays would depict 
all aircraft equipped with ADS-B or transponders. Pilots may be able to 
use this information to monitor and maintain safe separation from other 
aircraft with fewer instructions from ATC. At night and in poor visual 
conditions, pilots could also see where they are in relation to the 
ground using onboard avionics and terrain maps associated with a multi-
function display. The information would be clear and accurate 
regardless of inclement weather conditions.
    Also, like ATC, aircraft CDTIs could display precise locations of 
all ADS-B equipped aircraft and ground vehicles, along with data that 
shows their direction of movement in flight or on the airport surface. 
With this information, pilots would be able to follow the progress of 
other aircraft or ground vehicles using the cockpit display, and 
correlate that position by reference to outside visual cues. The 
increased position and traffic awareness would allow more efficient 
movement on airport surfaces by pilots.
    Aircraft equipped with ADS-B In capabilities could receive traffic 
information for other aircraft regardless of whether those aircraft are 
equipped with a functional ADS-B system. Aircraft equipped with ADS-B 
In would also be able to identify other ADS-B equipped aircraft 
regardless of the broadcast link being used. This comprehensive air 
traffic situational awareness would be provided by Traffic Information 
Service-Broadcast (TIS-B) until all aircraft are equipped with ADS-B 
Out, at which time TIS-B would be decommissioned and the information 
would be transmitted by ADS-R. Existing radar surveillance information 
is provided to ground stations and sent out on both 1090ES and UAT as a 
part of the TIS-B message.
    The FAA expects the following two services and five applications to 
be available to operators voluntarily equipping with ADS-B In:
    <bullet> Traffic Information Service-Broadcast (TIS-B). This is a 
ground-based uplink report of traffic that is under surveillance by 
ATC. During implementation of the ADS-B system, TIS-B would provide 
surveillance information on aircraft that are not yet ADS-B equipped. 
The ground infrastructure would support air-to-air operations by 
broadcasting TIS-B messages on both the 978 MHz UAT and 1090 MHz ES 
broadcast links for targets detected and reported by radar or other 
surveillance systems. TIS-B would be available during the transition 
period and until all affected aircraft are equipped for ADS-B Out. Once 
all aircraft are equipped to meet ADS-B Out performance requirements, 
TIS-B would be decommissioned as it would no longer be necessary since 
aircraft would receive traffic information through ADS-B.
    <bullet> Flight Information Service-Broadcast (FIS-B). FIS-B 
provides the

[[Page 56961]]

broadcast of weather and non-control advisory information providing 
users aeronautical information supporting safe and efficient 
operations. FIS-B products include, but are not limited to, graphical 
and textual weather reports and forecasts, NextGen radar precipitation 
information, special use airspace information, NOTAMS, electronic pilot 
reports, and other similar meteorological and aeronautical information. 
FIS-B products would be uplinked using the 978 MHz UAT broadcast link, 
but would not be available on the 1090 MHz ES broadcast link. The FIS-B 
service could accommodate additional products in the future. Both 
government and commercial sources would provide uplink products.
    The following applications would be available to all pilots whose 
aircraft are voluntarily equipped to receive ADS-B In messages:
    <bullet> Airport Surface Situational Awareness. This application 
would reduce the potential for deviations, errors, and collisions 
through an increase in pilots' situational awareness while operating an 
aircraft on the airport movement area. Pilots would use a flight deck 
display to increase awareness of other traffic positions on the airport 
movement area. Additionally, the display may be used to determine the 
position of ground vehicles, e.g., snowplows, emergency vehicles, tugs, 
follow-me vehicles, and airport maintenance vehicles, if they meet ADS-
B Out performance requirements. Surface vehicles operating on the 
movement area (runways and taxiways) would need to be ADS-B Out 
equipped.
    <bullet> Final Approach and Runway Occupancy Awareness. This 
application would reduce the likelihood of pilot errors associated with 
runway occupancy and would improve the capability of the flight crew to 
detect ATC errors. It involves using a cockpit display to depict the 
runway environment and display traffic from the surface up to 
approximately 1,000 feet AGL on final approach. It would be used by the 
flight crew to help determine runway occupancy.
    <bullet> Enhanced Visual Acquisition. This application would 
provide the pilots with enhanced traffic situational awareness in 
controlled and uncontrolled airspace and airports. The application uses 
a cockpit display to enhance out-of-the-window visual acquisition of 
air traffic. Pilots would refer to the display during the instrument 
scan to supplement visual observations. The display would be used to 
aid in initial detection of an aircraft or to receive further 
information on an aircraft that has been reported by ATC. The 
application provides the pilots with the relative range, altitude, and 
bearing of other aircraft.
    <bullet> Enhanced Visual Approach. This application would enhance 
sequential approaches for aircraft cleared to maintain visual 
separation from another aircraft on the approach in order to maintain 
visual approach procedure operation arrival rates even during periods 
of reduced visibility or obstructions to vision (e.g., haze, fog, and 
sunlight). Pilots would have a cockpit display of nearby traffic that 
would continually update identity and position information to assist 
the pilots with achieving and maintaining visual contact with relevant 
traffic. Additional information such as range and speed would be 
provided to assist pilots in monitoring their distance from the 
preceding aircraft. The display may also be used to monitor aircraft on 
approach to parallel runways.
    <bullet> Conflict Detection. This application would alert the pilot 
to potential conflicts with other aircraft and provide relevant traffic 
information. Aircraft equipped with a cockpit display have the 
capability to display aircraft location and projected flight path. More 
than simply displaying traffic, the application would alert pilots of 
developing conflicts. Also, the surveillance range afforded by ADS-B 
would enable alerts to be issued in time to resolve potential conflicts 
with minimum disruption to the flight path. The conflict detection 
application is an ADS-B-enabled capability for properly equipped 
aircraft and is not intended as a TCAS replacement.
    ADS-B In is not limited to the reception of these services and 
applications. The ability to receive ADS-B In messages provides a 
platform for services that may be developed in the future by the FAA or 
by independent vendors.
    Users with ADS-B In may also have greater predictability of flight 
duration because they would have more information on the state of air 
traffic and the procedures being used by air traffic controllers to 
handle traffic. Greater predictability of arrival and departure times 
could allow air carriers to have ground crews ready sooner, and with 
less margin of error. Shared situational awareness may also allow 
pilots to observe patterns in the flight of traffic around them and may 
increase the efficiency of their flight by allowing them to operate in 
concert with other traffic with less radio communication.

VI. FAA Experience With ADS-B

A. Capstone

    The Capstone project was initially proposed as an operational 
demonstration program for Alaska in the Bethel and Yukon-Kuskokwim (Y-
K) Delta area. Flights below 6,000 feet in the Y-K Delta are conducted 
in a non-radar environment. The only radar coverage in the area is 
high-altitude coverage for aircraft controlled from Anchorage. 
Capstone's traffic awareness function, which lets anyone with an ADS-B 
receiver see the locations and altitudes of Capstone-equipped aircraft, 
enhances situational awareness to aircraft operators in the Y-K Delta.
    Phase II of Capstone, which extended the Capstone program into 
Southeast Alaska, officially began in March 2003. The FAA is 
integrating Phase II of the Capstone program into the national ADS-B 
program. Statewide deployment of ADS-B is expected to be completed by 
2013.
    Special Federal Aviation Regulation (SFAR) 97 allows suitably 
equipped aircraft to conduct IFR Area Navigation (RNAV) operations in 
Alaska on published air traffic routes using TSO-C145a/C146a navigation 
systems as the only means of IFR navigation. It also allows pilots to 
conduct IFR en route RNAV operations in Alaska using Special Minimum En 
Route Altitudes that are outside the operational service volume of 
ground-based navigation aids. This SFAR opened more than 40,000 square 
miles of airspace that included more than 1,500 NM of new routes. As 
discussed previously, SFAR No. 97 would remain in effect to supplement 
the requirements of this proposal.
    According to FAA accident statistics compiled by the MITRE 
Corporation, the Capstone safety program reduced the aircraft fatal 
accident rates for Alaska part 135 operators equipped with Capstone 
avionics by 45%. While this accident reduction is not solely 
attributable to ADS-B, the ADS-B information in the flight deck did 
provide increased pilot awareness of surrounding traffic and directly 
contributed to the accident rate reduction. In addition, search and 
rescue efforts for individuals in equipped aircraft have been 
dramatically improved over efforts towards those in non-equipped 
aircraft. Knowing a more precise location of the aircraft's last known 
position has minimized the response times and reduced the search area.

B. Gulf of Mexico

    Air traffic across the Gulf of Mexico has experienced significant 
growth over

[[Page 56962]]

the past decade, at a rate twice that of domestic airspace. The 
northern portion of the Gulf of Mexico is home to one of the largest 
helicopter fleets in the world. More than 650 helicopters provide 
support for 5,500 off-shore oil and gas production platforms. The 
helicopter fleet in the Gulf of Mexico logs approximately 2.1 million 
operations per year. These operations are contained in a 500 mile area 
along the Texas, Louisiana, and Mississippi coastline, extending 250 
miles into the Gulf of Mexico. The majority of helicopter operations 
take place between the surface and 7,000 feet. Much of this fleet flies 
without the ability to communicate with or be seen by ATC, or to obtain 
current weather data. When IFR conditions are prevalent, capacity is 
reduced nearly 95%. On IFR days, many operators are forced to cancel 
flights due to the lack of both en route and destination weather 
information and surveillance. Adverse weather conditions impact the 
region an average of one day out of every four.
    On March 24, 2006, the National Traffic Safety Board (NTSB) issued 
safety recommendations A-06-19 through 23 to the FAA in response to a 
helicopter accident that occurred in the Gulf of Mexico on March 23, 
2004. Specifically, the NTSB recommended, in A-06-21, that ``FAA should 
ensure that the infrastructure for the National Automatic Dependent 
Surveillance-Broadcast Program in the Gulf of Mexico is operational by 
fiscal year 2010.''
    In May 2006, the FAA established a cooperative government/industry 
business relationship to enhance communications, weather, and 
surveillance capabilities in the Gulf of Mexico through a Memorandum of 
Agreement (MOA). Through the MOA, the FAA teamed with the Helicopter 
Association International and others to deliver a higher level of 
aviation service in the Gulf of Mexico. The FAA plans to build a Gulf 
of Mexico infrastructure to enhance low and high altitude voice 
communication and surveillance, and low altitude weather observation 
capability. While chiefly intended for helicopter use, the enhancements 
offer potential benefit to all aircraft operating in Gulf airspace. The 
MOA continues in effect for 5 years and can be renewed. The FAA plans 
to install communications equipment in the 2007/2008 timeframe, weather 
equipment in the 2008 timeframe, and surveillance equipment in the 
2008/2009 timeframe. The FAA expects initial operational capability of 
the communications, weather, and surveillance equipment in the 2009/
2010 timeframe.

C. UPS--Louisville

    The FAA and the United Parcel Service (UPS) are working together to 
implement a system at Louisville, Kentucky (SDF) airport that would 
increase airport capacity and efficiency while significantly reducing 
vulnerability to runway incursion events and reduce the events 
themselves. UPS and the FAA have developed a concept to create a system 
that would use ADS-B surveillance at SDF, along with a Surface 
Management System and a scheduling and sequencing system to meet the 
demands of the future. ADS-B Out is expected to be operational on 
certain UPS aircraft by fall 2007. UPS is also installing a CDTI 
display for certain proposed operational applications such as merging 
and spacing, Surface Area Moving Management, and CDTI Assisted Visual 
Spacing capability in all of its B-757, B-767, B-747-400, A-300, and 
MD-11 fleets.

D. Surveillance in Non-Radar Airspace

    Today, there are pockets of airspace across the NAS that are 
outside of radar coverage and are managed by ATC using non-radar 
procedural separation. While the FAA has not yet decided whether to 
place GBTs in these areas, it could decide to do so. Since the vast 
majority of the fleet would already be equipped with ADS-B Out, placing 
GBTs in these areas would result in the types of benefits experienced 
in Alaska and predicted for the Gulf of Mexico.
    Presently ATC controls IFR operations in non-radar airspace using 
inefficient separation techniques and is unable to provide many 
advisory services otherwise available in a surveillance environment. 
Consequently, non-radar separation between aircraft in a non-radar 
environment within the domestic U.S. is up to 10 minutes (80 miles for 
jet traffic) compared to 3 or 5 miles in a radar environment. Operators 
would realize significant efficiency gains, if ATC were able to utilize 
traffic monitoring techniques currently only available in a 
surveillance environment (e.g., aircraft vectoring and speed control).
    Surveillance capability also allows ATC to offer other safety-
related services to both VFR and IFR aircraft, including traffic safety 
alerts when aircraft that are on conflicting courses, minimum safe 
altitude warnings (MSAW), and navigational assistance.

VII. ADS-B in Other Countries

    The European Organisation for the Safety of Air Navigation, known 
as EUROCONTROL, a cooperative organization of 37 member states in 
Europe, is focused on developing a seamless, pan-European Air Traffic 
Management system. In support of its objective, EUROCONTROL is 
considering a plan to install ADS-B ground broadcast transceivers in 
European areas that do not have adequate radar coverage. EUROCONTROL 
proposed guidance is to use ADS-B for surveillance in medium density 
airspace where there is currently no surveillance capability.
    In April 2007, the Australian Civil Aviation Safety Authority 
(CASA) published a Notice of Final Rule Making (NFRM) \28\ adopting 
operational and technical standards for aircraft that are voluntarily 
equipped for ADS-B services in Australian airspace. CASA stated that it 
will not consider mandatory use of ADS-B until Airservices Australia 
makes a final decision on the replacement of its enroute radar systems. 
Until such determination is made, operators may choose to equip with 
ADS-B to operate in Australian airspace. Airservices Australia is 
installing ADS-B ground stations for operational use that can receive 
and process both RTCA DO-260 and DO-260A transmissions to apply a 5NM 
air traffic separation standard.\29\
---------------------------------------------------------------------------

    \28\ This NFRM summarizes the comments received in response to 
proposal 0601AS and presents CASA's evaluation of those comments. 
This document also sets forth the amendments for ADS-B equipage and 
related guidance material.
    \29\ The FAA's decision to propose performance standards that 
meet TSO-166a is because the FAA intends to use ADS-B transmissions 
to provide surveillance using the existing separation standards of 3 
NM in terminal environments and 5 NM miles in the enroute 
environment.
---------------------------------------------------------------------------

    NAV Canada is deploying ADS-B in northern Canada to provide 
surveillance in the airspace over Hudson Bay where there currently is 
no radar coverage today. Future deployments of ADS-B in Canadian 
airspace are targeted for the Northwest Territories and northern B.C., 
which also do not have radar coverage. NAV Canada anticipates having 
ADS-B in the rest of Canada as a replacement for, or complement to, 
radar.
    The FAA is working with EUROCONTROL, Airservices Australia and NAV 
CANADA to internationally harmonize operational concepts and minimum 
safety and performance requirements for ADS-B.

VIII. Alternatives to ADS-B

    Multilateration is a non-radar system that has limited deployment 
in the U.S. The FAA considered multilateration as an alternative to 
ADS-B. Multilateration is a process by which an aircraft's position is 
determined by measuring the time difference between the arrival of

[[Page 56963]]

the aircraft's signal to multiple receivers on the ground. At a 
minimum, multilateration requires upwards of four ground stations to 
deliver the same volume of coverage and integrity of information as 
ADS-B, due to the need to ``triangulate'' the aircraft's position. 
While both radar and multilateration meet today's surveillance needs, 
it would be substantially more costly to expand these systems than to 
implement ADS-B to meet future surveillance demands. Moreover, future 
uses of these systems would not provide a platform for air-to-air 
applications, as ADS-B does.
    Radars have different update rates, accuracies, ranges, and 
functions. Alternatively, since ADS-B employs one type of receiving 
equipment, it does not have to accommodate for transition between 
differing surveillance systems. The consistency of the signal and 
information could increase the productivity of air traffic controllers 
by eliminating the need to account for different surveillance systems 
and environments. The deployment of secondary surveillance as a backup 
would entail some of the costs, but these would be significantly less 
than the costs of a full NAS-wide secondary surveillance solution.

IX. Rulemaking Notices and Analyses

Paperwork Reduction Act

    This proposal contains the following new information collection 
requirements. As required by the Paperwork Reduction Act of 1995 (44 
U.S.C. 3507(d)), the FAA has submitted the information requirements 
associated with this proposal to the Office of Management and Budget 
for its review.
    Title: Automatic Dependent Surveillance-Broadcast (ADS-B) Out 
performance requirements to support air traffic control service.
    Summary: This proposal requires performance requirements for 
certain avionics equipment on aircraft operating in specified classes 
of airspace within the United States National Airspace System. The 
proposed rule would facilitate the use of ADS-B for aircraft 
surveillance by FAA air traffic controllers to accommodate the expected 
increase in demand for air transportation. In addition to accommodating 
the anticipated increase in operations, this proposal, if adopted, 
would provide aircraft operators with a platform for additional flight 
applications and services.
    Use of: This proposal would support the information needs of the 
FAA by requiring avionics equipment that continuously transmits 
aircraft information to be received by the FAA, via automation, for use 
in providing surveillance services.
    Respondents (including number of): The likely respondents to this 
proposed information requirement are stated in the chart below.
    Frequency: The FAA estimates that each respondent would incur costs 
of installing the equipment onboard the aircraft, as provided below. 
The FAA does not attribute any costs to each individual transmission 
from the electronics onboard the aircraft. Attempts to capture each 
aircraft transmission would be impossible and even if it could be 
captured, the cost would be minimal.
    Annual Burden Estimate: This proposal would result in unit aircraft 
costs for new equipment installation and associated labor as follows:

                                               ADS-B Equipment and Installation Hours & Cost & Respondents
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Aircraft unit costs--                         Installation costs by aircraft
                                         includes equipment and  ---------------------------------------------------------------------------
                                           installation costs                  Labor costs                          Labor hours               Number of
            Aircraft group                                       ---------------------------------------------------------------------------  operators
                                       --------------------------
                                            Low          High               Low                High               Low               High
--------------------------------------------------------------------------------------------------------------------------------------------------------
GA....................................       $4,328      $17,283  $2,250.................       $5,000  30....................           50          n/a
TurboProp.............................       12,906      463,706  minimal................       23,000  minimal...............          230        2,522
TurboJet..............................        3,862      135,736  minimal................       23,000  minimal...............          230          294
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: ADS-B Equipment could be hardware, software or combination of both.

    The agency is soliciting comments to--
    (1) Evaluate whether the proposed information requirement is 
necessary for the proper performance of the functions of the agency, 
including whether the information will have practical utility;
    (2) Evaluate the accuracy of the agency's estimate of the burden;
    (3) Enhance the quality, utility, and clarity of the information to 
be collected; and
    (4) Minimize the burden of collecting information on those who are 
to respond, including by using appropriate automated, electronic, 
mechanical, or other technological collection techniques or other forms 
of information technology. Individuals and organizations may send 
comments on the information collection requirement by January 3, 2008, 
and should direct them to the address listed in the Addresses section 
at the end of this preamble. Comments also should be faxed to the 
Office of Information and Regulatory Affairs, OMB, (202) 395-6974, 
Attention: Desk Officer for FAA.
    According to the 1995 amendments to the Paperwork Reduction Act (5 
CFR 1320.8(b)(2)(vi)), an agency may not collect or sponsor the 
collection of information, nor may it impose an information collection 
requirement unless it displays a currently valid OMB control number. 
The OMB control number for this information collection will be 
published in the Federal Register after the Office of Management and 
Budget approves it.

International Compatibility

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA policy to comply with ICAO 
SARPS to the maximum extent practicable. Considering that the long-term 
global capabilities of ADS-B are not yet fully defined, ICAO SARPS are 
still evolving and are not yet fully developed. However, the FAA 
researched existing ICAO requirements for ADS-B Out operations (using 
one of the ADS-B links, either 1090ES or UAT) to the maximum extent 
practicable. Specifically, the FAA reviewed applications to avionics 
and airframe manufacturers, air carriers, and general aviation 
operating under 14 CFR parts 91, 121, 125, or 135, and foreign air 
carriers conducting operations in U.S. airspace. The FAA has identified 
no differences with these proposed regulations.\30\

[[Page 56964]]

Regulatory Evaluation, Regulatory Flexibility Determination, 
International Trade Impact Assessment, and Unfunded Mandates Assessment

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 directs that each Federal agency 
shall propose or adopt a regulation only upon a reasoned determination 
that the benefits of the intended regulation justify its costs. Second, 
the Regulatory Flexibility Act of 1980 (Pub. L. 96-354) requires 
agencies to analyze the economic impact of regulatory changes on small 
entities. Third, the Trade Agreements Act (Pub. L. 96-39) prohibits 
agencies from setting standards that create unnecessary obstacles to 
the foreign commerce of the United States. In developing U.S. 
standards, this Trade Act requires agencies to consider international 
standards and, where appropriate, that they be the basis of U.S. 
standards. Fourth, the Unfunded Mandates Reform Act of 1995 (Pub. L. 
104-4) requires agencies to prepare a written assessment of the costs, 
benefits, and other effects of proposed or final rules that include a 
Federal mandate likely to result in the expenditure by State, local, or 
tribal governments, in the aggregate, or by the private sector, of $100 
million or more annually (adjusted for inflation with base year of 
1995). This portion of the preamble summarizes the FAA's analysis of 
the economic impacts of this proposed rule. We suggest readers seeking 
greater detail read the full regulatory impact analysis, a copy of 
which we have placed in the docket for this rulemaking.
    In conducting these analyses, FAA has determined that this proposed 
rule: (1) Has benefits that justify its costs, (2) is an economically 
``significant regulatory action'' as defined in section 3(f) of 
Executive Order 12866, (3) is ``significant'' as defined in DOT's 
Regulatory Policies and Procedures; (4) would have a significant 
economic impact on a substantial number of small entities; (5) would 
not create unnecessary obstacles to the foreign commerce of the United 
States; and (6) would impose an unfunded mandate on state, local, or 
tribal governments, or on the private sector by exceeding the threshold 
identified above. These analyses are summarized below.
---------------------------------------------------------------------------

    \30\ ICAO references: PANS-ATM, Doc 4444, Amendment 4 (24/11/
05), Procedures for Air Navigation Services--Air Traffic Management; 
Doc 9694, ICAO Manual of Air Traffic Services Data Link 
Applications; Annex 2, Rules of the Air; Annex 4, Aeronautical 
Charts; Annex 6 Part II, Operation of Aircraft; Annex 11, Air 
Traffic Services; Annex 15, Aeronautical Information Services; Doc 
9689, Manual for determination of separation minima; Circular 311, 
SASP Circular--ADS-B Comparative Assessment; Circular 278, National 
Plan for CNS/ATM Systems Guidance Material; Annex 10 Vol. IV, 
Amendment 77, Aeronautical Telecommunications; Doc 9871, Technical 
Provisions for Mode S Services and Extended Squitter (Approved draft 
to be published in 2006); Doc 9688, ICAO Manual on Mode S Specific 
Services.
---------------------------------------------------------------------------

Request for Comment
    While we welcome and encourage, all comments on the regulatory 
evaluation, we specifically request comment in the regulatory 
evaluation as follows:
    <bullet> We solicit comments from manufacturers of large category 
turbojet, regional turboprop and general aviation aircraft on when they 
intend to start delivering new aircraft to comply with the rule if 
enacted. We need clarification of the avionics currently installed on 
new production airplanes and expected enhancements that would occur 
without the rule. Lastly, we solicit comment regarding the remaining 
assumptions.
    <bullet> We assumed the weight for an ADS-B Out transponder, on a 
GA aircraft, would be about the same as weight as existing transponders 
and therefore the change would be negligible and there would be no 
additional weight or fuel burn costs. We request comments from industry 
on this assumption.
    <bullet> We request comments from industry on the estimated costs, 
maintenance intervals MTBF replacement, and MTTR requirements for the 
ADS-B Out transponder and position source units.
    <bullet> The FAA solicits comments on the benefits that we have 
identified and estimated and whether there are any potential benefits 
of ADS-B that we have not identified.
    <bullet> We solicit comments from the industry on what they expect 
avionics costs of equipping with ADS-B In to be as well as whether the 
industry will voluntarily equip and the benefits of ADS-B In equipage.
    <bullet> We request comments from the aviation industry about FAA 
surveillance deployment strategies that could permit acceleration of 
realized benefits.
    <bullet> The FAA seeks comment, with supportive justification, to 
determine the degree of hardship the proposed rule will have on these 
small entities.
    <bullet> Overall, in terms of competition, this rulemaking reduces 
small operators ability to compete. We request comments from industry 
on the results of the competitive analysis.
    <bullet> The FAA assumed that maintenance and replacement costs for 
ADS-B Out for GA aircraft equals zero because the maintenance and 
replacement times would occur beyond 2035. The FAA seeks comment on 
this assumption.
Total Benefits and Costs of this Rule
    The demand for air travel is growing in the U.S. and around the 
world. The FAA's forecasts project a doubling in U.S. airline passenger 
traffic by 2025. The forecasts also show strong growth for general 
aviation, especially with the advent of very light jets.
    The solution to managing the anticipated growth in the use of the 
NAS is the Next Generation Air Transportation System, or NextGen, which 
will assure the safe and efficient movement of people and goods as 
demand increases. NextGen will use technology to allow precise 
navigation, permit accurate real-time communication, and vastly improve 
situational awareness.
    ADS-B is the chosen new technology for surveillance in the NextGen 
system. It is a key component in achieving many of the goals set forth 
in the Next Generation Air Transportation System (NextGen) Integrated 
Plan.
    We review the following three alternatives for surveillance in this 
analysis:
    1. Baseline radar--maintain the current radar based surveillance 
system and replace radar facilities when they wear out;
    2. ADS-B--Aircraft operators equip to meet performance requirements 
proposed by the rule and the FAA provides surveillance services based 
on downlinked aircraft information.
    3. Multilateration--The FAA would provide surveillance using 
multilateration.
    The proposed rule requires aircraft to equip only with ADS-B Out 
when flying in certain airspace. Operators may choose to more fully 
equip with ADS-B In and Out, and so we also address these costs and 
benefits.
    The estimated cost of this proposed rule ranges from a low of $2.3 
billion ($1.6 billion at 7% present value) to a high of $8.5 billion 
dollars ($4.5 billion at 7% present value).\31\ These costs include 
costs to the government, as well as to the aviation industry and other 
users of the airspace, to deploy ADS-B and are incremental to 
maintaining surveillance via current technology (radar). The aviation 
industry would begin incurring costs for avionics equipage in 2012 and 
would incur total costs ranging from $1.27 billion ($670 million at 7% 
present value) \32\ to $7.46 billion ($3.6 billion at 7% present value) 
\33\ with an estimated midpoint of

[[Page 56965]]

$4.32 billion ($2.12 billion at 7% present value) \34\ from 2012 to 
2035.
---------------------------------------------------------------------------

    \31\ Costs at 3% present value range from $1.9 billion to $6.3 
billion.
    \32\ $950 million at 3% present value.
    \33\ $5.35 billion at 3% present value.
    \34\ $3.13 billion at 3% present value.
---------------------------------------------------------------------------

    The estimated quantified potential benefits of the proposed rule 
are about $10 billion ($2.7 billion at 7% present value) \35\ and 
primarily result from fuel, operating cost and time savings from more 
efficient flights.
---------------------------------------------------------------------------

    \35\ $5.48 billion at 3% present value.
---------------------------------------------------------------------------

    The proposed rule would make it more likely that aircraft operators 
would equip with ADS-B In equipment, which could result in estimated 
additional benefits of $3.9 billion ($1.0 billion at 7% present 
value).\36\ The additional cost of the ADS-B In ground segment is 
estimated at $533 million ($283 million at 7% present value).\37\ We 
did not estimate the cost for aircraft operators to equip with ADS-B In 
because we concluded the requirements for ADS-B In are insufficient in 
detail and do not yet support the development of a cost estimate. The 
FAA will continue to study ADS-B In technology and intends to provide 
an adoption cost estimate for the final rule. Benefits of both ADS-B In 
and Out have been estimated at $13.8 billion ($3.7 billion at 7% 
present value).\38\ Estimated costs of ADS-B In and Out (excluding ADS-
B In avionics costs), relative to the radar baseline, range from $2.8 
billion ($1.8 at 7% present value) \39\ to $9.0 billion ($4.8 at 7% 
present value).\40\
---------------------------------------------------------------------------

    \36\ $2.1 billion at 3% present value.
    \37\ $392 million when discounted by 3%.
    \38\ $7.6 billion at 3% present value.
    \39\ $2.3 billion at 3% present value.
    \40\ $6.7 billion at 3% present value.
---------------------------------------------------------------------------

    While we do not have estimates of ADS-B In avionics costs, we can 
derive an upper bound for what that cost cannot exceed if the ADS-B In 
and Out scenario is to be cost beneficial relative to radar for each of 
the two possibilities described below.
    Given that we have a range of costs (low to high) we considered two 
possibilities: (1) Low cost, and (2) high cost:
    <bullet> We concluded that ADS-B In and Out would be cost 
beneficial at a present value of 7% if the costs for the ADS-B Out 
avionics are low ($670 million at 7% present value) and the avionics 
costs for ADS-B In do not exceed $1.85 billion at 7% present value.
    <bullet> We also concluded that ADS-B In and Out would be cost 
beneficial at a 3% present value if the costs for the ADS-B Out 
avionics are low ($950 million at 3% present value) and the ADS-B In 
avionics costs do not exceed $5.3 billion at 3% present value or if the 
costs for the ADS-B Out avionics are high ($5.35 billion at 3% present 
value) and the ADS-B In avionics costs do not exceed $870 million.
    ADS-B is a critical component of the Next Generation Air 
Transportation System Plan (NextGen) that is being developed to 
transform today's radar-based aviation system to handle increased 
aviation demand. By itself, ADS-B presents significant benefits, but as 
a component of the NextGen system the benefits will substantially 
increase. The Draft Regulatory Impact Analysis has been placed in the 
docket for this rulemaking.

Reduced Carbon Dioxide Emissions

    Besides the cost savings made possible by this proposed rulemaking, 
there will also be potential environmental benefits. ADS-B is an 
enabling technology critical to the concept of operations for the Next 
Generation Air Transportation System (NextGen) plan. Under the NextGen 
operational concept there will be less fuel used on many flights 
because of fewer potential conflicts needing resolution, more efficient 
en route conflict resolution aircraft maneuvers, and more efficient 
taxi and ground idle operations. Additionally, having more precise 
knowledge of the position of an aircraft with ADS-B may assist the 
implementation of such environmentally friendly flight procedures like 
continuous descent arrivals (CDA) to be employed in higher density 
traffic times.
    The FAA estimates that between 2017 and 2035 ADS-B technology would 
allow more efficient handling of potential en route conflicts, which 
will result in a total of 410 million gallons of fuel savings in the 
national airspace system over that time period. This decrease in fuel 
use would result in about 4 million metric tons less carbon dioxide 
emissions.\41\ The increased use of continuous descent approaches that 
ADS-B would allow would lead to about 10 billion pounds of total fuel 
savings from 2017 through 2035. This would result in about 14 million 
tons less carbon dioxide emissions. Additionally, the FAA has estimated 
a decline in fuel use on airline flights over the Gulf of Mexico due to 
optimal routing because of this proposed rulemaking. This savings in 
fuel use would result in an additional cumulative decrease of 300,000 
metric tons of carbon dioxide emissions over the 2012 to 2035 time 
period.
---------------------------------------------------------------------------

    \41\ For more information on the methodology used to calculate 
this estimate, see ``ADS-B Benefits Enabled from Improved en Route 
Conflict Probe Performance'' in the docket established for this 
rulemaking. The specific data in this regulatory evaluation however, 
is more conservation than the data in the report just mentioned.
---------------------------------------------------------------------------

    Reduced fuel consumption will also translate into fewer emissions 
such as oxides of nitrogen, which potentially impact, both local air 
quality and climate (as a greenhouse gas emission), as well as 
hydrocarbons and carbon monoxide-both of which impact local air 
quality. Reduction in local air quality impacts associated with 
increasing capacity is vital in maintaining compliance with national 
ambient air quality standards.
    The FAA solicits comments on the benefits that we have identified 
and estimated and whether there are any potential benefits of ADS-B 
that we have not identified.

Initial Regulatory Flexibility Determination ADS-B

Introduction and Purpose of This Analysis
    The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA) 
establishes ``as a principle of regulatory issuance that agencies shall 
endeavor, consistent with the objectives of the rule and of applicable 
statutes, to fit regulatory and informational requirements to the scale 
of the businesses, organizations, and governmental jurisdictions 
subject to regulation. To achieve this principle, agencies are required 
to solicit and consider flexible regulatory proposals and to explain 
the rationale for their actions to assure that such proposals are given 
serious consideration.'' The RFA covers a wide-range of small entities, 
including small businesses, not-for-profit organizations, and small 
governmental jurisdictions.
    Agencies must perform a review to determine whether a rule will 
have a significant economic impact on a substantial number of small 
entities. If the agency determines that it will, the agency must 
prepare a regulatory flexibility analysis as described in the RFA.
    However, if an agency determines that a proposed or final rule is 
not expected to have a significant economic impact on a substantial 
number of small entities, section 605(b) of the 1980 RFA provides that 
the head of the agency may so certify and a regulatory flexibility 
analysis is not required. The certification must include a statement 
providing the factual basis for this determination, and the reasoning 
should be clear.
    The FAA believes that this proposal would result in a significant 
economic impact on a substantial number of small entities. The purpose 
of this analysis is

[[Page 56966]]

to provide the reasoning underlying the FAA determination.
    Under Section 603(b) of the RFA, the analysis must address:
    <bullet> Description of reasons the agency is considering the 
action,
    <bullet> Statement of the legal basis and objectives for the 
proposed rule,
    <bullet> Description of the record keeping and other compliance 
requirements of the proposed rule,
    <bullet> All federal rules that may duplicate, overlap, or conflict 
with the proposed rule,
    <bullet> Description and an estimated number of small entities to 
which the proposed rule will apply,
    <bullet> Analysis of small firms' ability to afford the proposed 
rule,
    <bullet> Estimation of the potential for business closures,
    <bullet> Conduct a competitive analysis,
    <bullet> Conduct a disproportionality analysis, and
    <bullet> Describe the alternatives considered.
Reasons Why the Rule Is Being Proposed
    Public Law 108-176, referred to as ``The Century of Aviation 
Reauthorization Act,'' was enacted December 12, 2003 (Pub. L. 108-176). 
This law set forth requirements and objectives for transforming the air 
transportation system to progress further into the 21st century. 
Section 709 of this statute requires the Secretary of Transportation to 
establish in the FAA a joint planning and development office (JPDO) to 
manage work related to the Next Generation Air Transportation System 
(NextGen). Among its statutorily defined responsibilities, the JPDO 
coordinates the development and utilization of new technologies to 
ensure that when available, they may be used to the fullest potential 
in aircraft and in the air traffic control system.
    The FAA, the National Aeronautics and Space Administration (NASA) 
and the Departments of Commerce, Defense, and Homeland Security have 
launched an effort to align their resources to develop and further the 
NextGen. The goals of NextGen, as stated in section 709, are addressed 
by this proposal and include:
    (1) Improve the level of safety, security, efficiency, quality, and 
affordability of the NAS and aviation services;
    (2) take advantage of data from emerging ground-based and space-
based communications, navigation, and surveillance technologies;
    (3) be scalable to accommodate and encourage substantial growth in 
domestic and international transportation and anticipating and 
accommodating continuing technology upgrades and advances; and
    (4) accommodate a wide range of aircraft operations, including 
airlines, air taxis, helicopters, general aviation, and unmanned aerial 
vehicles.
    The JPDO was also charged to create and carry out an integrated 
plan for NextGen. The NextGen Integrated Plan,\42\ transmitted to 
Congress on December 12, 2004, ensures that the NextGen system meets 
the air transportation safety, security, mobility, efficiency and 
capacity needs beyond those currently included in the FAA's Operational 
Evolution Plan (OEP). As described in the NextGen Integrated Plan, the 
current approach to air transportation, i.e., ground based radars 
tracking congested flyways and passing information among the control 
centers for the duration of the flights, is becoming operationally 
obsolete. The current system is increasingly inefficient and large 
increases in air traffic will only result in mounting delays or 
limitations in service for many areas.
---------------------------------------------------------------------------

    \42\ A copy of the Plan has been placed in the docket for this 
rulemaking.
---------------------------------------------------------------------------

    This growth will result in more air traffic than the present system 
can handle. The current method of handling traffic flow will not be 
able to adapt to the highest volume and density of it in the future. It 
is not only the number of flights but also the nature of the new growth 
that is problematic, as the future of aviation will be much more 
diverse than it is today. For example, a shift of 2 percent of today's 
commercial passengers to micro-jets that seat 4-6 passengers would 
result in triple the number of flights in order to carry the same 
number of passengers. Furthermore, the challenges grow as other non-
conventional aircraft, such as unmanned aircraft, are developed for 
special operations, e.g. forest fire fighting.
    The FAA believes that ADS-B technology is a key component in 
achieving many of the goals set forth in the plan. This proposed rule 
embraces a new approach to surveillance that can lead to greater and 
more efficient utilization of airspace. The NextGen Integrated Plan 
articulates several large transformation strategies in its roadmap to 
successfully creating the Next Generation System. This proposal is a 
major step toward strategically ``establishing an agile air traffic 
system that accommodates future requirements and readily responds to 
shifts in demand from all users.'' ADS-B technology would assist in the 
transition to a system with less dependence on ground infrastructure 
and facilities, and provide for more efficient use of airspace.
Statement of the Legal Basis and Objectives
    The FAA's authority to issue rules regarding aviation safety is 
found in Title 49 of the United States Code. Subtitle I, Section 106 
describes the authority of the FAA Administrator. Subtitle VII, 
Aviation Programs, describes in more detail the scope of the agency's 
authority.
    This rulemaking is promulgated under the authority described in 
Subtitle VII, Part A, Subpart I, Section 40103, Sovereignty and use of 
airspace, and Subpart III, section 44701, General requirements. Under 
section 40103, the FAA is charged with prescribing regulations on the 
flight of aircraft, including regulations on safe altitudes, 
navigating, protecting, and identifying aircraft, and the safe and 
efficient use of the navigable airspace. Under section 44701, the FAA 
is charged with promoting safe flight of civil aircraft in air commerce 
by prescribing regulations for practices, methods, and procedures the 
Administrator finds necessary for safety in air commerce.
    This proposal is within the scope of sections 40103 and 44701 since 
it proposes aircraft performance requirements that would meet advanced 
surveillance needs to accommodate the projected increase in operations 
within the National Airspace System (NAS). As more aircraft operate 
within the U.S. airspace, improved surveillance performance is 
necessary to continue to balance the growth in air transportation with 
the agency's mandate for a safe and efficient air transportation 
system.
Projected Reporting, Recordkeeping and Other Requirements
    We expect no more than minimal new reporting and recordkeeping 
compliance requirements to result from this proposed rule. Costs for 
the initial installation of new equipment and associated labor 
constitute a burden under the Paperwork Reduction Act and are accounted 
for in this document.
Overlapping, Duplicative, or Conflicting Federal Rules
    We are unaware that the proposed rule will overlap, duplicate or 
conflict with existing Federal Rules.
Estimated Number of Small Firms Potentially Impacted
    Under the RFA, the FAA must determine whether a proposed rule 
significantly affects a substantial

[[Page 56967]]

number of small entities. This determination is typically based on 
small entity size and cost thresholds that vary depending on the 
affected industry. Using the size standards from the Small Business 
Administration for Air Transportation and Aircraft Manufacturing, we 
defined companies as small entities if they have fewer than 1,500 
employees.\43\
---------------------------------------------------------------------------

    \43\ 13 CFR part 121.201, Size Standards Used to Define Small 
Business Concerns, Sector 48-49 Transportation, Subsector 481 Air 
Transportation.
---------------------------------------------------------------------------

    We considered the economic impact on small-business part 91, 121, 
and 135 operators. Many of the General Aviation (GA) aircraft are 
operating in part 91 are not for hire or flown for profit so we will 
not include these operators in our small business impact analysis.
    This proposed rule would become final in 2009 and fully effective 
in 2020. Although the FAA forecasts traffic and air carrier fleets to 
2030, our forecasts do not have the granularity to determine if an 
operator will still be in business or will still remain a small 
business entity. Therefore we will use current U.S. operator's fleet 
and employment in order to determine the number of operators this 
proposal would affect.
    We obtained a list of part 91, 121 and 135 U.S. operators from the 
FAA Flight Standards Service.\44\ Using information provided by the 
U.S. Department of Transportation Form 41 filings, World Aviation 
Directory and ReferenceUSA, operators that are subsidiary businesses of 
larger businesses and businesses with more than 1,500 employees were 
eliminated from the list of small entities. In many cases the 
employment and annual revenue data was not public and we did not 
include these companies in our analysis. For the remaining businesses, 
we obtained company revenue and employment from the above three 
sources.
---------------------------------------------------------------------------

    \44\ AFS-260.
---------------------------------------------------------------------------

    The methodology discussed above resulted in the following list of 
34 U.S. part 91, 121 and 135 operators, with less than 1,500 employees, 
who operate 341 airplanes. Due to the sparse amount of publicly 
available data on internal company financial statistics for small 
entities, it is not feasible to estimate the total population of small 
entities affected by this proposed rule. These 34 U.S. small entity 
operators are a representative sample to assess the cost impact of the 
total population of small businesses, who operate aircraft affected by 
this proposed rulemaking.

------------------------------------------------------------------------
                                                               Number of
                        Operator name                           aircraft
------------------------------------------------------------------------
Air 1ST Aviation Companies of Oklahoma, Inc..................          9
Air Flight Enterprises Inc...................................          2
Air Transport International..................................         12
Aircraft Charter Services Inc................................          2
Allegiant Air................................................         26
American Check Transport Inc.................................         11
Anaconda Aviation Corp.......................................          2
Arrow Services...............................................          2
Bankair Inc..................................................         10
Caribbean Sun Airlines.......................................          6
Champion Air.................................................         16
Copper Station Holdings, LLC.................................          1
EPPS Air Service, Inc........................................         11
ERA Aviation Inc.............................................          9
Executive Airlines...........................................         38
Falcon Air Express...........................................          4
GOJET Airlines...............................................         15
Lynden Air Cargo.............................................          6
Miami Air International......................................         11
Midwest Airlines.............................................         36
North American Airlines......................................          9
Northeast Aviation, Inc......................................          1
Northern Air Cargo...........................................         10
Omni Air International.......................................         16
Pace Airlines................................................          8
Premier Jets Inc.............................................          1
Professional Aviation Services...............................          4
Royal Air Freight, Inc.......................................          3
Ryan International Airlines..................................         12
Samaritan's Purse............................................          2
Sun Country Airlines.........................................         13
USA Jet Airlines.............................................         10
World Airways................................................         17
XTRA Airways.................................................          6
                                                              ----------
    Total....................................................        341
------------------------------------------------------------------------

Cost and Affordability for Small Entities
    To assess the cost impact to small business part 91, 121 and 135 
operators, we contacted manufacturers, industry associations, and ADS-B 
equipage providers to estimate ADS-B equipage costs. We requested 
estimates of airborne installation costs, by aircraft model, for the 
output parameters listed in the Equipment Specifications section of the 
Regulatory Evaluation.
    This proposed rule would become final in 2009 and fully effective 
in 2020. Although the FAA forecast traffic and air carrier fleets to 
2030, our forecasts do not have the granularity to determine if an 
operator will still be in business or will still remain a small 
business entity. Therefore we will use current U.S. operator's revenues 
and apply the industry-provided costs in order to determine if this 
proposal would have a significant impact on a substantial number of 
small entity operators.
    To satisfy the manufacturer's request to keep individual aircraft 
pricing confidential, we calculated a low, baseline, and high range of 
costs by equipment class. The baseline estimate equals the average of 
the low and high industry estimates. The dollar value ranges consist of 
a wide variety of avionics within each aircraft group. The aircraft 
architecture within each equipment group can vary, causing different 
carriage, labor and wiring requirements for the installation of ADS-B. 
Volume discounting versus single line purchasing also affects the 
dollar value ranges. On the low end, the dollar value may represent a 
software upgrade or OEM option change. On the high end, the dollar 
value may represent a new installation of upgraded transponder systems 
necessary to assure accuracy, reliability and safety. We used the 
estimated baseline dollar value cost by equipment class in determining 
the impact to small business entities.
    We estimated each operator's total compliance cost by multiplying 
the baseline dollar value cost, by equipment class, by the number of 
aircraft each small business operator currently has in its fleet. We 
summed these costs by equipment class and group. We then measured the 
economic impact on small entities by dividing the estimated baseline 
dollar value compliance cost for their fleet by the small entity's 
annual revenue. Each equipment group operated by a small entity may 
have to comply with different requirements in the proposed rule 
depending on the state the aircraft's avionics. In the ADS-B Out 
Equipage Cost Estimate section of the Regulatory Evaluation we detail 
our methodology to estimate operator's total compliance cost by 
equipment group.
    As shown in the following table, the ADS-B cost is estimated to be 
greater than two percent of annual revenues for 12 small entity 
operators and greater than one percent of annual revenues for 19 small 
entity operators.
BILLING CODE 4910-13-P

[[Page 56968]]

[GRAPHIC] [TIFF OMITTED] TP05OC07.008

BILLING CODE 4910-13-C
    Thus, from this sample population, the FAA determined that a 
substantial number of small entities would be significantly affected by 
the proposed rule. Every small entity who operates an aircraft in the 
airspace defined by this proposal would be required to install ADS-B 
out equipage and therefore would be affected by this rulemaking.
Business Closure Analysis
    For commercial operators, the ratio of present-value costs to 
annual revenue shows that 7 of 34 small business air operator firms 
analyzed would have rations in excess of five percent. Since many of 
the other commercial small business air operator firms do not make 
their annual revenue publicly available, it is difficult to assess the 
financial impact of this proposed rule on their business. To fully 
assess whether this proposed rule could force a small entity into 
bankruptcy requires more financial information than is publicly 
available.
    The FAA seeks comment, with supportive justification, to determine 
the degree of hardship, and feasible alternative methods of compliance, 
the proposed rule will have on these small entities.

[[Page 56969]]

Competitive Analysis
    The aviation industry is an extremely competitive industry with 
slim profit margins. The number of operators who entered the industry 
and have stopped operations because of mergers, acquisitions, or 
bankruptcy litters the history of the aviation industry.
    The FAA analyzed five years of operating profits for the affected 
small-entity operators listed above. We were able to determine the 
operating profit for 18 of the 34 small business entities. The FAA 
discovered that 33% of these 18 affected operator's average operating 
profit is negative. Only four of the 18 affected operators had average 
annual operating profit that exceeded $10,000,000. These results are 
shown in the following table.
[GRAPHIC] [TIFF OMITTED] TP05OC07.009

    In this competitive industry, cost increases imposed by this 
proposed regulation would be hard to recover by raising prices, 
especially by those operators showing an average five-year negative 
operating profit. Further, large operators may be able to negotiate 
better pricing from outside firms for inspections and repairs, so small 
operators may need to raise their prices more than large operators. 
These factors make it difficult for the small operators to recover 
their compliance costs by raising prices. If small operators cannot 
recover all the additional costs imposed by this regulation, market 
shares could shift to the large operators.
    Small operators successfully compete in the aviation industry by 
providing unique services and controlling costs. To the extent the 
affected small entities operate in niche markets enhances small 
entity's ability to pass on costs. Currently small operators are much 
more profitable than the established major scheduled carriers. This 
proposed rule would offset some of the advantages of older aircraft 
lower capital cost.
    Overall, in terms of competition, this rulemaking reduces small 
operators ability to compete. We request comments from industry on the 
results of the competitive analysis.
Disproportionality Analysis
    The disproportionately higher impact of the proposed rule on the 
fleets of small operators result in disproportionately higher costs to 
small operators. Due to the potential of fleet discounts, large 
operators may be able to negotiate better pricing from outside sources 
for inspections, installation, and ADS-B hardware purchases. Based on 
the percent of potentially affected current airplanes over the analysis 
period, small U.S. business operators may bear a disproportionate 
impact from the proposed rule.
    Comments received and final rule changes on regulatory flexibility 
issues will be addressed in the statement of considerations for the 
final rule.
Analysis of Alternatives
Alternative One
    The status quo alternative has compliance costs to continue the 
operation and commissioning of radar sites. The FAA rejected this 
status quo alternative because the ground based radars tracking 
congested flyways and passing information among the control centers for 
the duration of the flights is becoming operationally obsolete. The 
current system is not efficient enough to accommodate the estimated 
increases in air traffic, which would result in mounting delays or 
limitations in service for many areas.
Alternative Two
    This alternative would employ a technology called multilateration. 
Multilateration is a separate type of secondary surveillance system 
that is not radar and has limited deployment in the U.S. At a minimum, 
multilateration requires upwards of four ground stations to deliver the 
same volume of coverage and integrity of information as ADS-B, due to 
the need to ``triangulate'' the aircraft's position. Multilateration is 
a process wherein an aircraft position is determined using the 
difference in time of arrival of a signal from an aircraft at a series 
of receivers on the ground. Multilateration meets the need for accurate 
surveillance and is less costly than ADS-B (but more costly than 
radar), but cannot achieve the same level of benefits that ADS-B can. 
Multilateration would provide the same benefits as radar, but at a 
higher cost.
Alternative Three
    This alternative would provide relief by having the FAA provide an 
exemption to small air carriers from all requirements of this rule. 
This alternative would mean that the small air carriers would rely on 
the status quo ground based radars tracking their flights and passing 
information among the control centers for the duration of the flights. 
This alternative would require compliance costs to continue for

[[Page 56970]]

the commissioning of radar sites. Air traffic controller workload and 
training costs would increase having to employ two systems in tracking 
aircraft. Small entities may request ATC deviations prior to operating 
in the airspace affected by this proposal. It would also be contrary to 
our policy for one level of safety in part 121 operations to exclude 
certain operators simply because they are small entities. Thus, this 
alternative is not considered to be acceptable.
Alternative Four
    This alternative is the proposed ADS-B rule. ADS-B does not employ 
different classes of receiving equipment or provide different 
information based on its location. Therefore, controllers will not have 
to account for transitions between surveillance solutions as an 
aircraft moves closer or farther away from an airport. In order to meet 
future demand for air travel without significant delays or denial of 
service, ADS-B was found to be the most cost effective solution to 
maintain a viable air transportation system. ADS-B provides a wider 
range of services to aircraft users and could enable applications 
unavailable to multilateration or radar.
Trade Impact Assessment
    The Trade Agreements Act of 1979 (Pub. L. 96-39) prohibits Federal 
agencies from establishing any standards or engaging in related 
activities that create unnecessary obstacles to the foreign commerce of 
the United States. Legitimate domestic objectives, such as safety, are 
not considered unnecessary obstacles. The statute also requires 
consideration of international standards and, where appropriate, that 
they be the basis for U.S. standards.
    ICAO is developing a set of standards that are influenced by, and 
similar to, the U.S. RTCA developed standards. Initial discussions with 
the international community lead us to conclude that U.S. aircraft 
operating in foreign airspace would not have to add any equipment or 
incur any costs in addition to what they would incur to operate in 
domestic airspace under this proposed rulemaking. Foreign operators may 
incur additional costs to operate in U.S. airspace, if their national 
rules, standards and, current level of equipage are different than 
those required by this proposed rule. The FAA is actively engaged with 
the international community to ensure that the international and US. 
ADS-B standards are as compatible as possible. For a fuller discussion 
of what other countries are planning with regard to ADS-B, see Section 
VII of this preamble. By 2020 ICAO standards may change to harmonize 
with this proposed rule and foreign operators will not have to incur 
additional costs.
Unfunded Mandates Assessment
    Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare a written statement 
assessing the effects of any Federal mandate in a proposed or final 
agency rule that may result in an expenditure of $100 million or more 
(adjusted annually for inflation with the base year 1995) in any one 
year by State, local, and tribal governments, in the aggregate, or by 
the private sector; such a mandate is deemed to be a ``significant 
regulatory action.'' The FAA currently uses an inflation-adjusted value 
of $128.1 million in lieu of $100 million. This proposed rule is not 
expected to impose significant costs on small governmental 
jurisdictions such as state, local, or tribal governments, but the FAA 
calls for comment on whether this expectation is correct. However, this 
proposed rule would result in an unfunded mandate because it would 
result in expenditures in excess of an inflation-adjusted value of 
$128.1 million. We have considered three alternatives to this 
rulemaking, which are discussed in section 4.0 and in the regulatory 
flexibility analysis in section 7.

Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule under the principles and 
criteria of Executive Order 13132, Federalism. We determined that this 
action would not have a substantial direct effect on the States, on the 
relationship between the national Government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government, and therefore would not have federalism implications.

Environmental Analysis

    FAA Order 1050.1E identifies FAA actions that are categorically 
excluded from preparation of an environmental assessment or 
environmental impact statement under the National Environmental Policy 
Act in the absence of extraordinary circumstances. The FAA has 
determined this proposed rulemaking action qualifies for the 
categorical exclusion identified in paragraph 312f and involves no 
extraordinary circumstances.

Regulations That Significantly Affect Energy Supply, Distribution, or 
Use

    The FAA has analyzed this NPRM under Executive Order 13211, Actions 
Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use (May 18, 2001). We have determined that it is not 
a ``significant energy action'' under the executive order because it is 
not a ``significant regulatory action'' under Executive Order 12866, 
and it is not likely to have a significant adverse effect on the 
supply, distribution, or use of energy.

List of Subjects in 14 CFR Part 91

    Aircraft, Airmen, Air traffic control, Aviation safety, Reporting 
and recordkeeping requirements.

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration proposes to amend chapter I of title 14, Code of Federal 
Regulations, as follows:

PART 91--GENERAL OPERATING AND FLIGHT RULES

    1. The authority citation for part 91 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 1155, 40103, 40113, 40120, 44101, 
44111, 44701, 44709, 44711, 44712, 44715, 44716, 44717, 44722, 
46306, 46315, 46316, 46504, 46506-46507, 47122, 47508, 47528-47531, 
articles 12 and 29 of the Convention on International Civil Aviation 
(61 stat.1180).

    2. Amend Sec.  91.1 by revising paragraph (b) to read as follows:


Sec.  91.1  Applicability.

* * * * *
    (b) Each person operating an aircraft in the airspace overlying the 
waters between 3 and 12 nautical miles from the coast of the United 
States must comply with Sec. Sec.  91.1 through 91.21; Sec. Sec.  
91.101 through 91.143; Sec. Sec.  91.151 through 91.159; Sec. Sec.  
91.167 through 91.193; Sec.  91.203; Sec.  91.205; Sec. Sec.  91.209 
through 91.217; Sec.  91.221, Sec.  91.225; Sec. Sec.  91.303 through 
91.319; Sec. Sec.  91.323 through 91.327; Sec.  91.605; Sec.  91.609; 
Sec. Sec.  91.703 through 91.715; and Sec.  91.903.
* * * * *
    3. Revise Sec.  91.217 to read as follows:


Sec.  91.217  Data correspondence between automatically reported 
pressure altitude data and the pilot's altitude reference.

    (a) No person may operate any automatic pressure altitude reporting 
equipment associated with a radar beacon transponder--
    (1) When deactivation of that equipment is directed by ATC;
    (2) Unless, as installed, that equipment was tested and calibrated 
to transmit altitude data corresponding within 125 feet (on a 95 
percent probability basis) of the indicated or calibrated datum of the 
altimeter

[[Page 56971]]

normally used to maintain flight altitude, with that altimeter 
referenced to 29.92 inches of mercury for altitudes from sea level to 
the maximum operating altitude of the aircraft; or
    (3) Unless the altimeters and digitizers in that equipment meet the 
standards of TSO-C10b and TSO-C88, respectively.
    (b) After January 1, 2020, no person may operate any automatic 
pressure altitude reporting equipment associated with a radar beacon 
transponder or with ADS-B Out equipment unless the pressure altitude 
reported for ADS-B Out and Mode C/S is derived from the same source for 
aircraft equipped with both a transponder and ADS-B Out.
    4. Add Sec.  91.225 to read as follows:


Sec.  91.225  Automatic Dependent Surveillance-Broadcast (ADS-B) Out 
equipment and use.

    (a) After January 1, 2020, and unless otherwise authorized by ATC, 
no person may operate an aircraft below Flight Level 240 (FL240) and in 
airspace described in paragraph (b) of this section unless the aircraft 
is equipped with ADS-B Out equipment that:
    (1) Meets the performance requirements in TSO-C166a (1090ES), or 
later version; or
    (2) Meets TSO-C154b (UAT), or later version; and
    (3) Meets the requirements in part 91, Appendix H;
    (b) Airspace:
    (1) Class A airspace below FL240;
    (2) Class B and Class C airspace areas;
    (3) All aircraft in all airspace within 30 nautical miles of an 
airport listed in appendix D, section 1 of this part from the surface 
upward to 10,000 feet MSL;
    (4) All aircraft in all airspace above the ceiling and within the 
lateral boundaries of a Class B or Class C airspace area designated for 
an airport upward to 10,000 feet MSL.
    (c) After January 1, 2020, and unless otherwise authorized by ATC, 
no person may operate an aircraft at or above FL240 unless the aircraft 
is equipped with ADS-B Out equipment that:
    (1) Meets the performance requirements in TSO-C166a or later 
version; and
    (2) Meets the requirements of part 91, Appendix H.
    (d) The requirements of paragraphs (a) and (c) of this section, as 
appropriate, apply to:
    (1) All aircraft in Class E airspace over the Gulf of Mexico from 
the coastline of the United States out to 12 nautical miles at and 
above 3,000 feet MSL;
    (2) All aircraft, except for any aircraft that was not originally 
certificated with an electrical system, or which has not subsequently 
been certified with such a system installed, including balloons and 
gliders, in Class E airspace within the 48 contiguous states and the 
District of Columbia at and above 10,000 feet MSL.
    (e) The requirements of paragraphs (a), (c), and (d) of this 
section do not apply to any aircraft that was not originally 
certificated with an electrical system, or which has not subsequently 
been certified with such a system installed, including balloons and 
gliders, which may conduct operations without ADS-B Out in airspace 
within 30 nautical miles of an airport listed in appendix D, section 1 
of this part provided such operations are conducted:
    (1) Outside any Class B or Class C airspace area; and
    (2) Below the altitude of the ceiling of a Class B or Class C 
airspace area designated for an airport, or 10,000 feet MSL, whichever 
is lower.
    (f) Each person operating an aircraft equipped with ADS-B Out must 
operate this equipment in the transmit mode at all times except as 
otherwise directed by ATC.
    (g) Requests for ATC authorized deviations must be made to the ATC 
facility having jurisdiction over the concerned airspace within the 
time periods specified as follows:
    (1) For operation of an aircraft with an inoperative ADS-B Out, to 
the airport of ultimate destination, including any intermediate stops, 
or to proceed to a place where suitable repairs can be made or both, 
the request may be made at any time.
    (2) For operation of an aircraft that is not equipped with ADS-B 
Out, the request must be made at least one hour before the proposed 
operation.
    5. Amend appendix D to part 91 by revising section 1 introductory 
text to read as follows:

Appendix D to Part 91--Airports/Locations: Special Operating 
Restrictions

    Section 1. Locations at which the requirements of Sec.  
91.215(b)(2) and Sec.  91.225(b)(3) apply. The requirements of Sec.  
91.215(b)(2) and Sec.  91.225(b)(3) apply below 10,000 feet above 
the surface within a 30-nautical-mile radius of each location in the 
following list:
* * * * *
    6. Add appendix H to part 91 to read as follows;

Appendix H--Performance Requirements for Automatic Dependent 
Surveillance--Broadcast (Ads-B) Out

Section 1. Terms of Reference

    ADS-B Out is a function of an aircraft's onboard avionics that 
periodically broadcasts the aircraft's state vector (3-dimensional 
position and 3-dimensional velocity) and other required information 
as described in this appendix.
    ADS-B Out operating requirements are defined in 14 CFR 91.225.
    Navigation Accuracy Category for Position (NACp) specifies the 
accuracy of reported aircraft's position as defined in TSO-C166a and 
TSO-C154b.
    Navigation Accuracy Category for Velocity (NACv) specifies the 
accuracy of reported aircraft's velocity as defined in TSO-C166a and 
TSO-C154b.
    Navigation Integrity Category (NIC) specifies an integrity 
containment region around the aircraft's reported position, as 
defined in TSO-C166a and TSO-C154b.
    Navigation Position Sensor is the equipment installed onboard an 
aircraft used to process and transmit aircraft position (e.g. 
location, latitude and longitude, state vector) information.
    Surveillance Integrity Level (SIL) indicates the potential risk 
that the reported aircraft's position is outside the integrity 
containment region described by the NIC parameter, as defined in 
TSO-C166a and TSO-C154b.

Section 2. 1090ES and UAT Broadcast Links and Power Requirements

    (a) Aircraft operating above FL240 with equipment installed that 
meets the minimum performance requirements of TSO-C166a or later 
version, must meet the performance requirements of Class A1, A2, A3, 
or B1 equipment as defined in TSO-C166a or later version.
    (b) Aircraft operating in airspace designated for ADS-B Out and 
below FL240 must have equipment installed that meets the performance 
requirements of either:
    (1) Class A1, A2, A3 or B1 equipment as defined in TSO-C166a or 
later version; or
    (2) Class A1H, A2, A3, or B1 equipment as defined in TSO-C154b 
or later version.

Section 3. ADS-B Out Performance Requirements for NIC, NAC, and SIL

    (a) For aircraft broadcasting ADS-B Out as required under Sec.  
91.225(a), (c), and (d):
    (1) The aircraft's NACp for the positioning source must be 
greater than or equal to 9;
    (2) The aircraft's NACv for the positioning source must be 
greater than or equal to 1;
    (3) The aircraft's NIC must be greater than or equal to 7; and
    (4) The aircraft's SIL must be 2 or 3.
    (b) Changes in the NIC, NAC, or SIL must be broadcast within 10 
seconds.

Section 4. Minimum Broadcast Message Element Set for ADS-B Out

    Each aircraft must broadcast the following information, as 
defined in TSO-C166a or later version, or TSO-C154b or later 
version. The pilot must enter information for message elements (g)-
(k) of this section during the appropriate phase of flight:
    (a) The length and width of the aircraft;
    (b) An indication of the aircraft's lateral and longitudinal 
position;
    (c) An indication of the aircraft's barometric pressure 
altitude;
    (d) An indication of the aircraft's velocity;

[[Page 56972]]

    (e) An indication if TCAS II or ACAS is installed and operating 
in a mode that can generate resolution advisory alerts;
    (f) If an operable TCAS II or ACAS is installed, an indication 
if a resolution advisory is in effect;
    (g) An indication if the flight crew has selected to receive ATC 
services;
    (h) An indication of the Mode 3/A transponder code specified by 
ATC;
    (i) An indication of the aircraft's call sign that is submitted 
on the flight plan, or the aircraft's registration number;
    (j) An indication if the flight crew has identified an emergency 
and if so, the emergency status being transmitted;
    (k) An indication of the aircraft's ``IDENT'' to ATC;
    (l) An indication of the aircraft assigned ICAO 24-bit address;
    (m) An indication of the aircraft's emitter category;
    (n) An indication whether a cockpit display of traffic 
information (CDTI) is installed and operable; and
    (o) An indication of the aircraft's geometric altitude.

Section 5. ADS-B Latency Requirements

    (a) Upon receipt of the information by the aircraft antenna(s), 
the navigation position sensor must process the information in less 
than 0.5 seconds.
    (b) The processed information from the navigation position 
sensor must be transmitted in the ADS-B Out message in less than 1.0 
second.
    (c) The aircraft must transmit its position and velocity at 
least once per second while airborne or while moving on the airport 
surface.
    (d) The aircraft must transmit its position at least once every 
5 seconds while stationary on the airport surface.

    Issued in Washington, DC, on October 1, 2007.
Michael A. Cirillo,
Vice President, System Operations Services.
Rick Day,
Vice President, En Route and Oceanic Services.

[FR Doc. 07-4938 Filed 10-2-07; 9:08 am]
BILLING CODE 4910-13-P