
[Federal Register Volume 76, Number 241 (Thursday, December 15, 2011)]
[Proposed Rules]
[Pages 77939-77942]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-31451]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 91, 121, 125, 129, and 135


Proposed Provision of Navigation Services for the Next Generation 
Air Transportation System (NextGen) Transition to Performance-Based 
Navigation (PBN)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed policy and request for comments.

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SUMMARY: The Federal Aviation Administration (FAA) seeks comments on a 
proposed transition of the U.S. National Airspace System (NAS) 
navigation infrastructure to enable performance-based navigation (PBN) 
as part of the Next Generation Air Transportation System (NextGen). The 
FAA plans to transition from defining airways, routes and procedures 
using VHF Omni-directional Range (VOR) and other legacy navigation aids 
(NAVAIDs) \1\ towards a NAS based on Area Navigation (RNAV) everywhere 
and Required Navigation Performance (RNP) where beneficial. Such 
capabilities will be enabled largely by the Global Positioning System 
(GPS) and the Wide Area Augmentation System (WAAS). The FAA plans to 
retain an optimized network of Distance Measuring Equipment (DME) 
stations and a minimum operational network (MON) of VOR stations to 
ensure safety and continuous operations for high and low altitude en 
route airspace over the conterminous US (CONUS) and terminal operations 
at the Core 30 airports.\2\ The FAA is also conducting research on 
Alternate Positioning, Navigation and Timing (APNT) solutions that 
would enable further reduction of VORs below the MON.
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    \1\ Includes Tactical Air Navigation (TACAN) Azimuth, VOR/TACAN 
(VORTAC), VOR/DME, Non-Directional Beacon (NDB) operated by the FAA.
    \2\ Core 30 airports are those with significant activity serving 
major metropolitan areas and also serve as hubs for airline 
operations, found at http://aspmhelp.faa.gov/index.php/Core_30.
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    In addition, the FAA plans to satisfy any new requirements for 
Category I instrument operations with WAAS localizer performance with 
vertical guidance (LPV) procedures. A network of existing Instrument 
Landing Systems (ILS) would be sustained to provide alternative 
approach and landing capabilities to continue recovery and dispatch of 
aircraft during GPS outages.
    This transition would be consistent with the FAA's NextGen 
Implementation Plan (NGIP), NAS Enterprise Architecture (EA), and other 
documentation. More information is available on the FAA's NextGen Web 
site at http://www.faa.gov/nextgen and the EA Web site at https://nasea.faa.gov.

DATES: Comments must be received on or before March 7, 2012.

ADDRESSES: Send comments identified by Docket No. FAA-2011-1082 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 Docket Operations, M-30; U.S. 
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room 
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery or Courier: Take comments to Docket 
Operations 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 Docket Operations at (202) 493-2251.
    Privacy: The FAA will post all comments it receives, without 
change, to http://www.regulations.gov, including any personal 
information the commenter provides. Using the search function of the 
docket Web site, anyone can find and read the electronic form of all 
comments received into any FAA dockets, including the name of the 
individual sending the comment (or signing the comment for an 
association, business, labor union, etc.). DOT's complete Privacy Act 
Statement can be found in the Federal Register published on April 11, 
2000 (65 FR 19477-19478) as well as at http://DocketsInfo.dot.gov.

FOR FURTHER INFORMATION CONTACT: Mr. Greg Joyner, AJW-911, Navigation 
Services, Federal Aviation Administration, 800 Independence Avenue SW., 
Washington, DC 20591; telephone: (202) 493-5721.

[[Page 77940]]


SUPPLEMENTARY INFORMATION:

The Proposal

Purpose

    This notice announces the FAA's proposed strategy to meet 
requirements for air navigation service in the United States. The FAA 
is committed to maintaining the highest levels of safety, capacity, and 
efficiency in the NAS while transitioning from the legacy station-
referenced system of airways, routes and procedures to a performance-
based system providing flexible point-to-point navigation enabled by 
geospatial positioning, navigation, and timing (PNT) infrastructure and 
aircraft advanced navigation systems.

Transition to PBN for En Route, Terminal and Approach Operations in 
CONUS

    Many NextGen benefits depend on PBN, specifically RNAV and RNP 
routes, arrivals, departures, instrument approaches and other 
procedures to increase capacity and efficiency, and reduce aircraft 
noise and emissions while enhancing safety. All of these operations are 
enabled primarily by GPS and WAAS.
    GPS provides a level of service that supports lateral navigation 
for en route through non-precision instrument approaches. GPS is an 
internationally accepted navigation system, standardized by the 
International Civil Aviation Organization (ICAO), and has been approved 
for use by many countries. Additional information concerning GPS can be 
found at www.gps.gov and www.pnt.gov. The U.S. government has committed 
to maintaining GPS services in accordance with the Standard Positioning 
Service Performance Standard of September 2008. The U.S. is improving 
GPS services by adding a second frequency which will make GPS more 
resistant to unintentional radio frequency interference (RFI) sources.
    WAAS is a GPS augmentation system for aviation use that has been 
operational since 2003 and is used to improve the accuracy, integrity, 
and availability of GPS. WAAS also improves the availability of GPS to 
support PBN operations, even if several GPS satellites were to go out 
of service. WAAS is a satellite-based augmentation system (SBAS) 
standardized by ICAO. Compatible systems are operational in Japan and 
Europe, and other SBASs are in development in India and Russia.
    Even though basic and augmented GPS services enable all of the PBN 
capabilities for NextGen, the signals are vulnerable to scheduled and 
unscheduled outages. For example, the U.S. government regularly 
conducts scheduled testing in the NAS that impacts GPS use in selected 
regions. Unscheduled GPS outages have been caused by interference from 
intentional or unintentional sources of RFI. The FAA will ensure 
sufficient infrastructure is provided to mitigate the effects of 
scheduled GPS outages in designated areas and unscheduled outages which 
could otherwise significantly disrupt air commerce.
    The FAA also provides a network of distance measuring equipment 
(DME) that enable aircraft with suitable RNAV avionics to fly RNAV 
routes and terminal procedures where sufficient DME coverage exists. 
(See FAA Advisory Circular (AC) 90-100A, U.S. Terminal and En Route 
Area Navigation (RNAV) Operations.) In the near term, the FAA plans to 
enhance DME facilities to provide unrestricted RNAV operations for DME/
DME and DME/DME/Inertial Reference Unit (IRU) equipped aircraft 
operating in Class A airspace over the CONUS and in the vicinity of the 
Core 30 airports. Over the longer term, the FAA is investigating other 
APNT solutions to satisfy PNT requirements for all users in the event 
of a loss of GPS.
    Since VORs do not enable RNAV, RNP, or Automatic Dependent 
Surveillance-Broadcast (ADS-B) operations, the FAA plans to reduce 
costs by drawing down the number of FAA-provided VORs. Currently, over 
80% of the 967 VORs in the NAS inventory are past their economic 
service life and cost the FAA more than $110M per year to operate. 
Likewise, replacement parts are becoming increasingly difficult to 
obtain. The replacement of all of the VORs would cost over $1.0B. 
Therefore, the FAA is planning a gradual discontinuance (removal from 
service) of VOR facilities in CONUS to a minimum operational network 
(MON). The MON would enable aircraft anywhere in the CONUS to proceed 
safely to a destination with a GPS-independent approach within 100 nm. 
MON coverage is planned to be provided at altitudes above 5,000 feet 
above ground level (AGL). The FAA would also retain VORs to support 
international arrival airways from the Atlantic, Pacific, Caribbean, 
and at the Core 30 airports. The existing U.S. legacy navigation aids 
outside CONUS will be retained until a longer-term solution can be 
coordinated with users. The drawdown of VORs to a MON would be 
completed no later than January 1, 2020.
    In considering VORs for discontinuance, each facility will be 
evaluated on its own merits. The FAA will convene a working group that 
will develop a candidate list of VORs for discontinuance using relevant 
operational, safety, cost, and economic criteria. As part of the 
process, this working group will engage aviation industry stakeholders 
and other members of the public for input.
    Suitably equipped RNAV aircraft can continue to fly the existing 
Victor Airways and Jet Routes, Standard Terminal Arrivals (STAR), and 
Departure Procedures (DP) even if their associated VORs are not 
operating, by the use of RNAV substitution as described in AC 90-108, 
Use of Suitable Area Navigation (RNAV) Systems on Conventional Routes 
and Procedures. Existing airways, routes, and procedures eventually 
would be replaced by RNAV Q (high) and T (low) Routes, and RNAV STARs 
and DPs. VORs are also used for the Hazardous In-flight Weather 
Advisory Service (HIWAS) broadcast and voice communication with FAA 
Flight Service Stations. These services are not planned to be impacted 
by this proposal.
    WAAS supports vertically-guided approach operations, called 
Localizer Performance with Vertical guidance (LPV). These approaches 
are equivalent to Category I ILS, but do not require any radio 
navigation equipment at or near the airport. WAAS provides LPV coverage 
throughout CONUS, Alaska, and most of Canada and Mexico. By 2016, the 
FAA expects to provide instrument approach procedures with LPV or 
localizer performance (LP) non-precision lines of minima to all 
qualified instrument runways in CONUS and Alaska (see Advisory Circular 
AC 150/5300-13, Airport Design, Appendix 16). In order to maximize 
operational benefits and take advantage of the cost savings associated 
with WAAS, the FAA no longer intends to establish new Category I ILSs 
using Facilities and Equipment (F&E) funding.
    ILSs that are funded by grants from the Airport Improvement Program 
(AIP) will continue as an eligible project per the authorizing statute. 
However, the FAA is considering programmatic changes under AIP that 
would favor WAAS for new precision approaches at airports, rather than 
ILS. The FAA Office of Airports will engage with airport stakeholders 
and associations on these potential changes.
    Existing ILSs would provide an alternative approach and landing 
capability in support of recovery and dispatch of aircraft during GPS 
outages. ILSs would provide the precision approach and landing segment 
for APNT.

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    For all approach procedures, airports will continue to be required 
to meet airfield design and infrastructure requirements appropriate for 
the approach visibility levels set forth in AC 150/5300-13.

Future Plans

    Unaugmented GPS is capable of providing the accuracy and integrity 
required by the FAA's ADS-B Out regulations (14 CFR 91.225 and 91.227) 
that were effective August 31, 2010 and have a compliance date of 
January 1, 2020. However, at this time, WAAS augmentation is the only 
service that provides the 99.9 percent availability (equivalent to 
radar) needed for ADS-B. Operators that equip with other position 
sources, such as Receiver Autonomous Integrity Monitoring (RAIM) based 
GPS, may experience periods of unavailability that limit their access 
to the airspace. The FAA expects that positioning from GPS combined 
with future positioning sources such as the L5 GPS signal and/or other 
GNSS signals, and GPS tightly integrated with inertial navigation 
systems, will also provide 99.9 percent availability.
    The FAA is conducting research on APNT for service beyond 2020. The 
FAA will consider, in consultation with the users, whether the MON may 
be further reduced after an APNT solution is selected and available. 
The FAA is also evaluating the use of the Ground-Based Augmentation 
System (GBAS) in addition to ILS to provide Category II/III approach 
services.

Review of Navigation Equipage Requirements

    FAA regulations addressing the operational requirements to carry 
navigation equipment in aircraft are set forth in 14 CFR parts 91, 121, 
125, 129, and 135. Operators should be familiar with their specific 
requirements. The following paragraphs provide an overview of those 
requirements to assist in understanding the context for the 
radionavigation services described in this Notice.

Suitable Equipage for the Route To Be Flown

    The aircraft equipage rules are performance-based and the aircraft 
must have equipment appropriate for the route to be flown, including en 
route, departure, arrival, and instrument approach procedures. 
Operators planning to fly a variety of different routes and procedures 
must carry equipment suitable for the different routes and procedures.
    FAA guidance describing the navigation equipment ``suitable'' to 
the route to be flown is provided in the Aeronautical Information 
Manual and in a series of advisory circulars (see AC Nos. 90-100, 90-
101, 90-105, and 90-107). Equipment is considered suitable if it has 
been demonstrated to provide the accuracy, integrity and reliability 
for the operation and the necessary radionavigation service is provided 
for the planned route of flight. For conventional ground-based routes 
and procedures, suitable equipment can be directly inferred from the 
type of procedure (e.g., a VOR receiver would be suitable for operation 
on a Jet Route). RNAV systems, enabled by GPS, WAAS, or DME/DME/IRU 
(DDI), are suitable for a variety of operations including:
    [cir] Operation on Victor Airways, Jet Routes, terminal arrivals, 
departures, and approach procedures, including the initial and missed 
approach portions of an ILS instrument approach (based on AC 90-108);
    [cir] Operation on RNAV routes (Q routes and T routes);
    [cir] Operation on RNAV arrivals and departures;
    [cir] Operation on RNAV (GPS) approaches (excluding DDI);
    [cir] Operation on RNAV (RNP) approaches (excluding DDI).
    Operators must ensure that performance requirements can be met for 
the intended operations during flight planning. Due to integrity 
limitations of unaugmented GPS, aircraft using unaugmented GPS 
navigation equipment under IFR must be equipped with an approved and 
operational alternate means of navigation so that the aircraft can 
proceed safely to a landing at a suitable airport. This limitation also 
applies to required alternates: When a planned alternate is required, 
that alternate cannot be predicated on GPS in any way (as the primary 
approach aid, or as the means to accomplish the initial, intermediate 
or missed approach of an ILS, RNAV, or VOR approach).
    General aviation aircraft using WAAS equipment under IFR do not 
require an alternate means of navigation, due to the improved 
reliability of WAAS. However in non-normal conditions resulting in the 
loss of WAAS services (for example catastrophic failure of the WAAS 
satellites), the FAA will advise WAAS users that the GPS-only 
restrictions should be applied until such time as WAAS service can be 
restored. Aircraft equipped only with WAAS would be supported by air 
traffic control in the event of a catastrophic failure of satellite 
navigation.
    The planned use of GPS or WAAS during periods when GPS may be 
unavailable (e.g., test events identified through NOTAM as areas in 
which GPS may be unavailable) is not appropriate. In those areas and 
during the test, aircraft must be equipped with other equipment 
suitable for the planned operation (route of flight, altitude, etc.). 
However, pilots may use GPS or WAAS during flight if onboard equipment 
indicates service is available.
    RNAV systems using multiple DME signals are also suitable for many 
of the same operations. DME has several limitations compared to GPS or 
WAAS: the coverage of the service is not universal, so the operator 
must verify that it is available over the planned route of flight; and 
DME navigation is not currently capable of providing the more precise 
accuracy that is needed for approach and departure operations.

Two Independent Systems

    FAA regulations applicable to domestic operations for commerce or 
for hire require a second system capable of reversion or contingency 
operations during non-normal conditions, including regional- or system-
wide effects that could reasonably occur. The rules applicable to those 
operations require two independent navigation systems appropriate to 
the route to be flown, or one system that is suitable and a second, 
independent backup capability that allows the operator to proceed 
safely and land at a different airport, and the aircraft must have 
sufficient fuel (reference 14 CFR 121.349, 125.203, 129.17, and 
135.165). These rules ensure the safety of the operation by preventing 
a single point of failure.
    The requirements for a second system apply to the entire set of 
equipment needed to achieve the navigation capability, not just the 
individual components of the system such as the radionavigation 
receiver. For example, in order to use two RNAV systems to comply with 
the requirements, the aircraft must be equipped with two independent 
radionavigation receivers and two independent navigation computers 
(e.g., flight management systems). Alternatively, to comply with the 
requirements using a single RNAV system with an installed and operable 
VOR capability, the VOR capability must be independent of the FMS. The 
MON described in this notice would continue to allow this equipage to 
fulfill the above requirements for operating within U.S. airspace.
    To satisfy the requirement for two independent navigation systems, 
if the primary navigation system is GPS-based, the second system must 
be independent of GPS (e.g., VOR or DDI). This allows continued 
navigation in case of failure of the GPS or WAAS

[[Page 77942]]

services. Recognizing that GPS interference and test events resulting 
in the loss of GPS services have become more common, the FAA requires 
operators conducting IFR operations under 14 CFR 121.349, 125.203, 
129.17 and 135.165 to retain a non-GPS navigation capability consisting 
of either DME/DME, IRU or VOR for en route and terminal operations, and 
VOR and/or ILS for final approach. Since this system is to be used as a 
reversionary capability, single equipage is sufficient.

Instructions for Submission of Comments

    Interested parties are invited to provide comments on the proposal. 
Comments that provide the factual basis supporting the views and 
suggestions presented would be particularly helpful in developing 
reasoned decisions on the proposal.
    Communications should identify docket numbers (FAA Docket No. FAA-
2011-1082 and be submitted in triplicate to the Docket Management 
Facility (see ADDRESSES section for address and phone number).
    All communications received on or before the specified closing date 
for comments will be considered before taking action on the proposal. 
The proposal contained in this action may be changed in light of 
comments received. All comments submitted will be available for 
examination in the public docket both before and after the closing date 
for comments. A report summarizing each substantive public contact with 
FAA personnel concerned with this proposal will be filed in the docket.

Availability of Proposal

    An electronic copy of this document may be downloaded through the 
Internet at http://www.regulations.gov.
    You may review the public docket containing the proposal, any 
comments received, and any final disposition in person in the Dockets 
Office (see ADDRESSES section for address and phone number) between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays. An 
informal docket may also be examined during normal business hours at 
the office of Docket Operations, M-30; U.S. Department of 
Transportation (DOT), 1200 New Jersey Avenue SE., Room W12-140, West 
Building Ground Floor, Washington, DC 20590-0001.

    Issued in Washington, DC, on December 1, 2011.
Phillip Leman,
Acting Manager, Navigation Services.
[FR Doc. 2011-31451 Filed 12-14-11; 8:45 am]
BILLING CODE 4910-13-P


