Federal Register / Vol. 72, No. 193 / Friday, October 5, 2007 / Proposed Rules 56947 

Authority: 49 U.S.C. 106(g), 40113, 44701. 

§ 39.13 [Amended] 

2. The FAA amends § 39.13 by adding 

the following new airworthiness 

directive: 

Honeywell International Inc. (formerly 

AlliedSignal Inc. and Garrett Turbine 

Engine Co.): Docket No. FAA–2007–

29092; Directorate Identifier 2007–NE–

30–AD. 

Comments Due Date 

(a) The Federal Aviation Administration 

(FAA) must receive comments on this 

airworthiness directive (AD) action by 

December 4, 2007. 

Affected ADs 

(b) None. 

Applicability 

(c) This AD applies to Honeywell 

International Inc. ATF3–6–4C, ATF3–6A–3C, 

and ATF3–6A–4C turbofan engines equipped 

with part number (P/N) 3002070–1 low 

pressure compressor (LPC) aft shaft. These 

engines are installed on, but not limited to, 

Dassault Aviation Fan Jet Falcon Series G 

(Falcon 20G/HU25), and Dassault Aviation 

Mystere-Falcon 200 airplanes. 

Unsafe Condition 

(d) This AD results from reports of eight 

LPC aft shafts found cracked during 

fluorescent penetrant inspection (FPI). We 

are issuing this AD to prevent uncoupling 

and overspeed of the low pressure turbine, 

which could result in uncontained engine 

failure and damage to the airplane. 

Compliance 

(e) You are responsible for having the 

actions required by this AD performed within 

the compliance times specified in Table 1 

and Table 2 of this AD, unless the actions 

have already been done. 

TABLE 1.—ATF3–6A–4C TURBOFAN ENGINES, LPC AFT SHAFT REPLACEMENT COMPLIANCE SCHEDULE

For ATF3–6A–4C turbofan engines, if the 

cycles-since-new (CSN) on the effective 

date of this AD are: 

Then replace the LPC aft shaft: 

(1) 6,500 or more CSN .............................. Within an additional 100 cycles-in-service (CIS). 

(2) 5,000 to 6,499 CSN ............................. Within an additional 800 CIS, but not more than 6,600 CSN, whichever occurs first. 

(3) 4,000 to 4,999 CSN ............................. Within an additional 1,500 CIS, but not more than 5,800 CSN, whichever occurs first. 

(4) Fewer than 4,000 CSN ........................ Within an additional 2,000 CIS, but not more than 5,500 CSN, whichever occurs first. 

TABLE 2.—ATF3–6–4C AND ATF3–6A–3C TURBOFAN ENGINES, LPC AFT SHAFT REPLACEMENT COMPLIANCE

SCHEDULE

For ATF3–6–4C and ATF3–6A–3C turbofan engines, if the CSN on the effective 

date of this AD are: 

Then replace the LPC aft shaft: 

(1) 4,400 or more CSN .............................. Within an additional 100 CIS. 

(2) 3,600 to 4,399 CSN ............................. Within an additional 500 CIS, but not more than 4,500 CSN, whichever occurs first. 

(3) 3,300 to 3,599 CSN ............................. Within an additional 700 CIS, but not more than 4,100 CSN, whichever occurs first. 

(4) Fewer than 3,300 CSN ........................ Within an additional 1,000 CIS, but not more than 4,000 CSN, whichever occurs first. 

LPC Aft Shaft Replacement 

(f) Using the compliance schedule in Table 

1 or Table 2 of this AD as applicable, remove 

the LPC aft shaft P/N 3002070–1, from 

service, and install a serviceable LPC aft 

shaft. 

Definition 

(g) For the purpose of this AD, a 

serviceable LPC aft shaft is an aft shaft with 

a P/N not referenced in this AD. 

Alternative Methods of Compliance 

(h) The Manager, Los Angeles Aircraft 

Certification Office, has the authority to 

approve alternative methods of compliance 

for this AD if requested using the procedures 

found in 14 CFR 39.19. 

Related Information 

(i) Honeywell International Inc. Service 

Bulletin No. ATF3–72–6240, Revision 1, 

dated May 14, 2007, pertains to the subject 

of this AD. 

(j) Contact Joseph Costa, Aerospace 

Engineer, Los Angeles Aircraft Certification 

Office, FAA, Transport Airplane Directorate, 

3960 Paramount Blvd., Lakewood, CA 

90712–4137; e-mail: joseph.costa@faa.gov; 

telephone: (562) 627–5246; fax: (562) 627–

5210. 

Issued in Burlington, Massachusetts, on 

October 1, 2007. 

Peter A. White, 

Acting Manager, Engine and Propeller 

Directorate, Aircraft Certification Service. 

[FR Doc. E7–19684 Filed 10–4–07; 8:45 am] 

BILLING CODE 4910–13–P 

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). 

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: 

• Federal eRulemaking Portal: Go to 

http://www.regulations.gov and follow 

the online instructions for sending your 

comments electronically. 

• Mail: Send comments to the Docket 

Management Facility; U.S. Department 

of Transportation, 1200 New Jersey 

Avenue, SE., West Building Ground 


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Floor, Room W12–140, Washington, DC 

20590–0001. 

• 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. 

• 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—performancebased 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 everincreasing 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, 


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1The Plan was submitted to Congress on 

December 12, 2004. 

2A copy of the Plan has been placed in the docket 

for this rulemaking. 

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. 

4An aircraft without an operating transponder 

may still be observed by ATC using primary radar, 

but the aircraft will not have an identifying tag. 

5The FAA currently separates aircraft by 5 NM 

in the en route environment and 3 NM in the 

terminal environment. 

6While 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 

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. 

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. 

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

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


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surveillance during the transition period of ADS–

B avionics equipage. 

7An 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. 

8For 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. 

9See Sections IV. later in the preamble for a 

detailed discussion of ADS–B Out and V. for a 

detailed discussion of ADS–B In. 

10Traffic 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. 

11Flight 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. 

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. 

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. 

ADS–B technology already has been 

demonstrated successfully in Alaska via 

the Capstone program.8 In Alaska, radar 

coverage is either very limited or nonexistent. ADS–B provides a level of 

surveillance performance that 

previously did not exist and has 

resulted in increases in both efficiency 

and capacity. 

‘‘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

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-toair) 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. 

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 


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12A 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. 

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 1090ESequipped 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 


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13Airborne Collision Avoidance System (ACAS) 

is comparable to TCAS II and is specified for use 

in Europe. 

14RTCA, 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. 

15TSO–C166a superseded TSO–C166. 

(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 noncommercial 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. 

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. 

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. 

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 selfseparation. 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 


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16The aircraft’s navigation position sensor is 

discussed in detail in section IV.4. of this preamble. 

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. 

(c) An indication of the aircraft’s 

barometric pressure altitude. This 

message element would provide ATC 

with the aircraft’s altitude information. 

Currently, § 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 § 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 § 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 


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17CDTI 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. 

18Surveillance applications are discussed further 

in Section V of this NPRM. 

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: 

• Light (ICAO)—7,000 kg (15,500 lbs) 

or less. 

• Small aircraft—7,000 kg to 34,000 

kg (15,500 lbs to 75,000 lbs). 

• Large aircraft—34,000 kg to 136,000 

kg (75,000 lbs to 300,00 lbs). 

• High vortex large (i.e., B–757). 

• Heavy aircraft (ICAO)—136,000 kg 

(300,000 lbs) or more. 

• 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. 

(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. 

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 


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56956 Federal Register / Vol. 72, No. 193 / Friday, October 5, 2007 / Proposed Rules 

19ADS–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. 

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. 

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 NASbased 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 


yshivers on PROD1PC62 with PROPOSALS
Federal Register / Vol. 72, No. 193 / Friday, October 5, 2007 / Proposed Rules 56957 

20Final Program Requirements for Surveillance 

and Broadcast Services, En Route and Oceanic 

Services, Air Traffic Organization, Federal Aviation 

Administration. 

21See section IV.c.2. for a further discussion of 

the airspace where ADS–B Out would be required. 

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

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 


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56958 Federal Register / Vol. 72, No. 193 / Friday, October 5, 2007 / Proposed Rules 

22Transponder with Automatic Altitude 

Reporting Capability Requirement, 53 FR 4306; 

February 12, 1988. 

23This 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. 

24There 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. 

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. 

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 § 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 

§ 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

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 § 91.215, 

proposed § 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

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 


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Federal Register / Vol. 72, No. 193 / Friday, October 5, 2007 / Proposed Rules 56959 

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. 

26See 14 CFR 91.103. 

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. 

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

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, reroute, 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-bycase basis), or direction to exit the 

present airspace. 

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

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 groundbased 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 


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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 ‘‘rebroadcasts’’ 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: 

• Traffic Information ServiceBroadcast (TIS–B). This is a groundbased 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. 

• Flight Information ServiceBroadcast (FIS–B). FIS–B provides the 


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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: 

• 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. 

• 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. 

• 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. 

• 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. 

• 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 nonradar 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 


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28This 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. 

29The 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. 

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 SurveillanceBroadcast 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 nonradar 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

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 


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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 

Continued 

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 group 

Aircraft unit costs—includes equipment and installation costs Installation costs by aircraft 

Number of 

operators 

Low High 

Labor costs Labor hours 

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


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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. 

31Costs 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. 

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. 

Request for Comment 

While we welcome and encourage, all 

comments on the regulatory evaluation, 

we specifically request comment in the 

regulatory evaluation as follows: 

• 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. 

• 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. 

• 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. 

• 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. 

• 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. 

• We request comments from the 

aviation industry about FAA 

surveillance deployment strategies that 

could permit acceleration of realized 

benefits. 

• The FAA seeks comment, with 

supportive justification, to determine 

the degree of hardship the proposed rule 

will have on these small entities. 

• 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. 

• 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 


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34 $3.13 billion at 3% present value. 

35 $5.48 billion at 3% present value. 

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. 

41For 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. 

$4.32 billion ($2.12 billion at 7% 

present value) 34 from 2012 to 2035. 

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. 

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

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: 

• 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. 

• 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 radarbased 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. 

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-forprofit 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 


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42A copy of the Plan has been placed in the 

docket for this rulemaking. 

to provide the reasoning underlying the 

FAA determination. 

Under Section 603(b) of the RFA, the 

analysis must address: 

• Description of reasons the agency is 

considering the action, 

• Statement of the legal basis and 

objectives for the proposed rule, 

• Description of the record keeping 

and other compliance requirements of 

the proposed rule, 

• All federal rules that may duplicate, 

overlap, or conflict with the proposed 

rule, 

• Description and an estimated 

number of small entities to which the 

proposed rule will apply, 

• Analysis of small firms’ ability to 

afford the proposed rule, 

• Estimation of the potential for 

business closures, 

• Conduct a competitive analysis, 

• Conduct a disproportionality 

analysis, and 

• 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. 

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 


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43 13 CFR part 121.201, Size Standards Used to 

Define Small Business Concerns, Sector 48–49 

Transportation, Subsector 481 Air Transportation. 

44AFS–260. 

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

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. 

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. 

Operator name Number 

of 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 


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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. 


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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 smallentity 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. 

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 


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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 § 91.1 by revising paragraph 

(b) to read as follows: 

§ 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 §§ 91.1 through 91.21; 

§§ 91.101 through 91.143; §§ 91.151 

through 91.159; §§ 91.167 through 

91.193; § 91.203; § 91.205; §§ 91.209 

through 91.217; § 91.221, § 91.225; 

§§ 91.303 through 91.319; §§ 91.323 

through 91.327; § 91.605; § 91.609; 

§§ 91.703 through 91.715; and § 91.903. 

* * * * * 

3. Revise § 91.217 to read as follows: 

§ 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 


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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 § 91.225 to read as follows: 

§ 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 § 91.215(b)(2) and 

§ 91.225(b)(3) apply. The requirements of 

§ 91.215(b)(2) and § 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 § 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; 


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(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 

DEPARTMENT OF HOMELAND 

SECURITY 

Coast Guard 

33 CFR Part 165 

[CCGD05–07–092] 

RIN 1625–AA00 

Safety Zone: Christmas Holiday Boat 

Parade and Fireworks, Appomattox 

River, Hopewell, VA 

AGENCY: Coast Guard, DHS. 

ACTION: Notice of proposed rulemaking. 

SUMMARY: The Coast Guard proposes to 

establish a 600 foot radius safety zone 

in the vicinity of Hopewell, VA centered 

on position 37–19.18′ N/077–16.93′ W 

(NAD 1983) in support of the Christmas 

Holiday Boat Parade and Fireworks 

Event. This action is intended to restrict 

vessel traffic on the Appomattox River 

as necessary to protect mariners from 

the hazards associated with fireworks 

displays. 

DATES: Comments and related material 

must reach the Coast Guard on or before 

November 5, 2007. 

ADDRESSES: You may mail comments 

and related material to Commander, 

Sector Hampton Roads, Norfolk Federal 

Building, 200 Granby St., 7th Floor, 

Attn: Lieutenant Junior Grade TaQuitia 

Winn, Norfolk, VA 23510. Sector 

Hampton Roads maintains the public 

docket for this rulemaking. Comments 

and material received from the public, 

as well as documents indicated in this 

preamble as being available in the 

docket, will become part of this docket 

and will be available for inspection or 

copying at the Norfolk Federal Building 

between 9 a.m. and 2 p.m., Monday 

through Friday, except Federal holidays. 

FOR FURTHER INFORMATION CONTACT: 

Lieutenant Junior Grade TaQuitia Winn, 

Assistant Chief, Waterways 

Management Division, Sector Hampton 

Roads at (757) 668–5580. 

SUPPLEMENTARY INFORMATION: 

Request for Comments 

We encourage you to participate in 

this rulemaking by submitting 

comments and related material. If you 

do so, please include your name and 

address, identify the docket number for 

this rulemaking, CGD05–07–092, and 

indicate the specific section of this 

document to which each comment 

applies, and give the reason for each 

comment. Please submit all comments 

and related material in an unbound 

format, no larger than 81⁄2 by 11 inches, 

suitable for copying. If you would like 

to know they reached us, please enclose 

a stamped, self-addressed postcard or 

envelope. We will consider all 

comments and material received during 

the comment period. We may change 

this proposed rule in view of them. 

Public Meeting 

We do not plan to hold a public 

meeting, but you may submit a request 

for a meeting by writing to the 

Commander, Sector Hampton Roads at 

the address under ADDRESSES explaining 

why one would be beneficial. If we 

determine that one would aid this 

rulemaking, we will hold one at a time 

and place announced by a later notice 

in the Federal Register. 

Background and Purpose 

On December 1, 2007, the Christmas 

Holiday Boat Parade and Fireworks 

event will be held on the Appomattox 

River in Hopewell, VA. Due to the need 

to protect mariners and spectators from 

the hazards associated with the 

fireworks display, vessel traffic will be 

temporarily restricted within 600 feet of 

the display. 

Discussion of Proposed Rule 

The Coast Guard proposes to establish 

a 600 foot radius safety zone on 

specified waters of the Appomattox 

River in the vicinity of Hopewell, VA 

centered on position 37–19.18′ N/077– 

16.93′ W (NAD 1983). This regulated 

area will be established in the interest 

of public safety during the Christmas 

Holiday Boat Parade and Fireworks 

event and will be enforced from 6 p.m. 

on December 1, 2007 to 8 p.m. on 

December 2, 2007. General navigation in 

the safety zone will be restricted during 

the event. Except for participants and 

vessels authorized by the Captain of the 

Port or his designated Coast Guard 

Representative on scene, no person or 

vessel may enter or remain in the 

regulated area. 

Regulatory Evaluation 

This proposed rule is not a 

‘‘significant regulatory action’’ under 

section 3(f) of Executive Order 12866, 

Regulatory Planning and Review, and 

does not require an assessment of 

potential costs and benefits under 

section 6(a)(3) of that Order. The Office 

of Management and Budget has not 

reviewed it under that Order. 

We expect the economic impact of 

this proposed rule to be so minimal that 

a full Regulatory Evaluation under the 

regulatory policies and procedures of 

DHS is unnecessary. Although this 

proposed regulation would restrict 

access to the regulated area, the effect of 

this rule will not be significant because: 

(i) The safety zone will be in effect for 

a limited duration of time; and, (ii) the 

Coast Guard will provide notifications 

via maritime advisories so mariners can 

adjust their plans accordingly. 

Small Entities 

Under the Regulatory Flexibility Act 

(5 U.S.C. 601–612), we have considered 

whether this proposed rule would have 

a significant economic impact on a 

substantial number of small entities. 

The term ‘‘small entities’’ comprises 

small businesses, not-for-profit 

organizations that are independently 

owned and operated and are not 

dominant in their fields, and 

governmental jurisdictions with 

populations of less than 50,000. 


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