[Federal Register Volume 62, Number 68 (Wednesday, April 9, 1997)]
[Rules and Regulations]
[Pages 17480-17489]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-8367]


      

[[Page 17479]]

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Part III





Department of Transportation





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Federal Aviation Administration



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14 CFR Part 91



Reduced Vertical Separation Minimum Operations; Final Rule

  Federal Register / Vol. 62, No. 68 / Wednesday, April 9, 1997 / Rules 
and Regulations  

[[Page 17480]]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 91

[Docket No. 28870; Amdt No. 91-254]
RIN 2120-AE51


Reduced Vertical Separation Minimum Operations

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: The Federal Aviation Administration (FAA) is establishing 
requirements for operations of U.S.-registered aircraft in airspace 
designated as Reduced Vertical Separation Minimum (RVSM) airspace. RVSM 
refers to airspace between flight level (FL) 290 and FL 410, with 
assigned altitudes separated by a minimum of 1,000 feet rather than the 
2,000 foot minimum separation currently required above FL 290. The 
current requirement is based on navigation equipment with a level of 
accuracy that necessitated a 2,000 foot buffer. Modern navigation 
equipment permits more precise navigation, including altitude control. 
These regulations require operators and their aircraft to be approved 
in accordance with new requirements, in order to operate in RVSM 
specified airspace. The regulations ensure that operators and their 
aircraft are properly qualified and equipped to conduct flight 
operations while separated by 1,000 feet, and ensure that compliance 
with the RVSM requirements is maintained. This amendment makes more 
tracks and altitudes available for air traffic control to assign to 
operators, thus increasing efficiency of operations and air traffic 
capacity. This action maintains a level of safety equal to or greater 
than that provided by the current regulations. RVSM will be applied in 
designated areas, with the first area being certain flight levels in 
the North Atlantic (NAT) Minimum Navigation Performance Specifications 
(MNPS) airspace.

DATES: This final rules is effective April 9, 1997. Comments must be 
submitted on or before June 9, 1997.

ADDRESSES: Substantive comments on this action should be delivered or 
mailed, in triplicate, to: Federal Aviation Administration, Office of 
the Chief Counsel, Attention: Rules Docket (AGC-200), Room 915-G, 
Docket No. 28870, 800 Independence Avenue, SW., Washington, DC 20591. 
Comments delivered must be marked Docket No. 28870. Substantive 
comments also may be submitted electronically to the following Internet 
address: [email protected]. Comments may be examined in Room 915G 
weekdays between 8:30 a.m. and 5:00 p.m., except on Federal holidays.

FOR FURTHER INFORMATION CONTACT:
Mr. Roy Grimes, AFS-400, Technical Programs Division, Flight Standards 
Service, Federal Aviation Administration, 800 Independence Avenue, SW., 
Washington, DC 20591, telephone (202) 267-3734.

SUPPLEMENTARY INFORMATION: 

Substantive Comments Invited

    This action is a product of international agreements under which 
the international aviation community, including the United States, is 
prepared to and plans to begin operational testing of the RVSM 
procedures in certain altitudes on March 27, 1997. Arriving air 
traffic, having departed Europe and separated at RVSM altitudes, cannot 
as a practical matter arrive in oceanic airspace controlled by the 
United States, all needing to be reassigned to a pre-RVSM separation 
altitude. Unless this rule is implemented by March 27, 1997, there 
would have to be major delays for westbound NAT traffic in airspace 
that the FAA does not control, to avoid a significant safety problem.
    Because the United States international commitments in this matter 
cannot otherwise reasonably be met and because of the potential safety 
problem for aircraft entering U.S.-controlled oceanic airspace without 
the benefit of this rule, the FAA is publishing this action as a final 
rule without an opportunity for public comment. It should be noted, 
however, that this action has been developed through the international 
committee process, a variety of related program meetings, and a formal 
public meeting in 1993. No significant adverse comment was received.
    If an individual believes that a significant salient issue has been 
overlooked, that person is invited to comment by submitting such 
written data, views, or arguments as they may desire. Comments should 
identify the regulatory docket number and should be submitted in 
triplicate to the Rules Docket address specified above. Because this 
rule was developed as a result of an international agreement, comments 
deemed substantive will be presented for consideration and reviewed by 
the international community under the auspices of ICAO. If considered 
salient, the comment will be included for use by all participating 
member States.
    All comments received will be available, both before and after the 
closing date for comments, in the Rules Docket for examination by 
interested persons. Commenters wishing the FAA to acknowledge receipt 
of their comments must include a preaddressed, stamped postcard on 
which the following statement is made: ``Comments to Docket No. 
28870.'' The postcard will be date stamped and returned to the 
commenter.

Availability of This Document

    An electronic copy of this document may be downloaded using a modem 
and suitable communications software from the FAA regulations section 
of the Fedworld electronic bulletin board service (telephone 703-321-
3339), the Federal Register's electronic bulletin board service 
(telephone: 202-512-1661), or the FAA's Aviation Rulemaking Advisory 
Committee Bulletin Board Service (telephone: 202-267-5948).
    Internet users may reach the FAA's web page at http://www.faa.gov 
or the Federal Register's webpage at http://www.access.gpo/su__docs for 
access to recently published rulemaking documents.
    Any person may obtain a copy of this document by submitting a 
request to the Federal Aviation Administration, Office of Rulemaking, 
ARM-1, 800 Independence Avenue, SW., Washington, DC 20591, or by 
calling (202) 267-9677. Communications must identify the docket number 
of this rule.
    Persons interested in being placed on the mailing list for future 
rulemaking actions should request from the above office a copy of 
Advisory Circular No. 11-2A, Notice of Proposed Rulemaking Distribution 
System, that describes the application procedure.

Background

Statement of the Problem

    With air traffic increasing annually worldwide, FAA airspace 
planners and their international counterparts continually study methods 
of enhancing the air traffic control (ATC) system's ability to 
accommodate this traffic in a safe and efficient manner. The traffic 
problem has become particularly acute in the NAT airspace, where the 
number of flight operations increased 30 percent from 1988 through 
1992, according to the NAT Traffic Forecasting Group. The forecast 
indicates that traffic will rise 60 percent over the 1992 level of 
228,200 operations by 2005. Currently, 27 percent of operations in the 
NAT airspace receive clearances on tracks and to altitudes other than 
those

[[Page 17481]]

requested by the operators in their filed flight plans because of 
airspace limitations. These flights are conducted at less than optimum 
tracks and altitudes for the aircraft, resulting in time and fuel 
inefficiencies.
    One limitation on air traffic management at high altitudes is the 
required vertical separation. Whereas at lower altitudes air traffic 
controllers can assign aircraft operating under Instrument Flight Rules 
(IFR) altitudes a minimum of 1,000 feet apart, above FL 290, required 
vertical separation is a minimum of 2,000 feet.

    Note: Flight levels are stated in digits that represent hundreds 
of feet. The term flight level is used to describe a surface of 
constant atmospheric pressure related to a reference datum of 29.92 
inches of mercury. Rather than adjusting altimeters for changes in 
atmospheric pressure, pilots base altitude readings above the 
transition altitude [in the United States, 18,000 feet] on this 
standard reference. FL 290 represents 29,000 feet; FL 310 represents 
31,000 feet, and so on.)

    The 2,000 foot vertical separation minimum applied above FL 290 in 
U.S. and international airspace dates to the 1950's. At that time, 
high-altitude flight was possible for only a limited number of military 
aircraft, and inaccuracies in altitude-keeping systems were evident 
above FL 290. (``Altitude-keeping'' means the accuracy in the vertical 
plane with which an aircraft adheres to its assigned pressure altitude 
using the aircraft altitude-keeping and barometric altimeter systems.) 
However, advances in technology eventually gave transport and general 
aviation aircraft the ability to operate at higher altitudes, resulting 
in increased traffic along high-altitude routes.
    The 2,000 ft minimum vertical separation restricts the number of 
flight levels available, even though many more air carrier and general 
aviation aircraft are capable of high altitude operations now than when 
the standard was established. Flight levels 310, 330, 350, 370, and 390 
are the flight levels at which aircraft crossing between North America 
and Europe operate most economically, thus causing congestion at peak 
hours. One solution to air traffic management limitations would be to 
make available other flight levels, such as 320, 340, 360, and 380. 
Exhaustive technical studies show that a 1,000 ft minimum vertical 
separation is feasible and safe. The solution is based on marked 
improvement in altitude-keeping technology and provides relief from the 
fuel and time inefficiencies being seen in the NAT MNPS airspace.

History

    Rising traffic volume and fuel costs, which made flight at fuel 
efficient altitudes a priority for operators, sparked an interest in 
the early 1970's in implementing RVSM above FL 290. In April 1973, the 
Air Transport Association of America (ATA) petitioned the FAA for a 
rule change to reduce the vertical separation minimum to 1,000 feet for 
aircraft operating above FL 290. The petition was denied in 1977 in 
part because (1) aircraft altimeters had not been improved 
sufficiently, (2) improved maintenance and operational standards had 
not been developed, and (3) altitude correction was not available in 
all aircraft. In addition, the cost of modifying nonconforming aircraft 
was prohibitive. The FAA concluded that granting the ATA petition at 
that time would have adversely affected safety.
    Nevertheless, the FAA recognized the potential benefits of RVSM 
under certain circumstances and continued to review technological 
developments, committing extensive resources to studying aircraft 
altitude-keeping performance and necessary criteria for safely reducing 
vertical separation above FL 290. These benefits and data showing that 
implementing RVSM is technically feasible have been demonstrated in 
studies conducted cooperatively in international forums, as well as 
separately by the FAA.
    Because of the high standard of performance and equipment required 
for RVSM, the FAA foresees initial introduction of RVSM in oceanic 
airspace where special navigation performance standards already exist. 
(Special navigation areas require high levels of long-range navigation 
precision due to the separation standard applied). RVSM implementation 
in such airspace requires an increased level of precision demanded of 
operators, aircraft, and vertical navigation systems.
    In 1997, RVSM is planned only for one such special navigation area 
of operation, the NAT MNPS, established in the International Civil 
Aviation Organization (ICAO) NAT Region. In designated NAT MNPS 
airspace, tracks are spaced 60 nautical miles (nm) apart. On these 
tracks, aircraft are separated vertically by 2000 feet. All aircraft 
operating in this airspace must be appropriately equipped and capable 
of meeting the MNPS standards. Operators must follow procedures that 
ensure the standards are met, and flightcrews must be trained and 
qualified to meet the MNPS standards. Each operator, aircraft, and 
navigation system combination must receive and maintain authorization 
to operate in the NAT MNPS. The NATSPG Central Monitoring Agency for 
the NAT Systems Planning Group monitors NAT aircraft fleet performance 
to ensure that a safe operating environment is maintained.
    FAA data indicate that the altitude-keeping performance of most 
aircraft flying in the NAT could meet the standards for RVSM 
operations. The FAA and ICAO research to determine the feasibility of 
implementing RVSM in the NAT MNPS included the following four efforts:
    1. FAA Vertical Studies Program. This program began in mid-1981, 
with the objectives of collecting and analyzing data on aircraft 
performance in maintaining assigned altitude, developing program 
requirements to reduce vertical separation, and providing technical and 
operational representation on the various working groups studying the 
issue outside the FAA.
    2. RTCA Special Committee (SC)-150. RTCA, Inc., (formerly Radio 
Technical Commission for Aeronautics) is an industry organization in 
Washington, DC, that addresses aviation technical requirements and 
concepts and produces recommended standards. When the FAA hosted a 
public meeting in early 1982 on vertical separation, it was recommended 
that RTCA be the forum for development of minimum system performance 
standards for RVSM. RTCA SC-150 was formed in March 1982 to develop 
minimum system performance requirements, identify required improvements 
to aircraft equipment and changes to operational procedures, and assess 
the impact of the requirements on the aviation community. SC-150 served 
as the focal point for the study and development of RVSM criteria and 
programs in the United States from 1982 to 1987, including analysis of 
the results of the FAA Vertical Studies Program.
    3. ICAO Review of the General Concept of Separation Panel (RGCSP). 
In 1987, the FAA concentrated its resources for the development of RVSM 
programs in the ICAO RGCSP. The U.S. delegation to the ICAO RGCSP used 
the material developed by SC-150 as the foundation for U.S. positions 
and plans on RVSM criteria and programs. The panel's major conclusions 
were:
     RVSM is ``technically feasible without imposing 
unreasonably demanding technical requirements on the equipment.''
     RVSM provides ``significant benefits in terms of economy 
and en route airspace capacity.''
     Implementation of RVSM on either a regional or global 
basis requires ``sound operational judgment supported

[[Page 17482]]

by an assessment of system performance based on: Aircraft altitude-
keeping capability, operational considerations, system performance 
monitoring, and risk assessment.''
    4. NATSPG and the NATSPG Vertical Separation Implementation Group 
(VSIG).
    The NATSPG Task Force was established in 1988 to identify the 
requirements to be met by the future NAT Region air traffic services 
system; to design the framework for the NAT airspace system concept; 
and to prepare a general plan for the phased introduction of the 
elements of the concept. The objective of this effort was to permit 
``significant increases in airspace capacity and improvements in flight 
economy.'' At the meeting of the NATSPG in June 1991, all of the NAT 
air traffic service provider States, as well as the International Air 
Transport Association (IATA) and International Federation of Airline 
Pilots Association (IFALPA), endorsed the Future NAT Air Traffic 
Services System Concept Description developed by the NATSPG Task Force. 
With regard to the implementation of RVSM, the Concept Description 
concludes that ``priority must be given to implementation of this 
measure as it is believed to be achievable within the early part of the 
concept timeframe.'' NATSPG's initial goal was to implement RVSM 
between 1996 and 1997. To meet this goal, the NATSPG established the 
VSIG in June 1991 to take the necessary actions to implement RVSM in 
the NAT. These actions included:
     Programs and documents to approve aircraft and operators 
to conduct flight in the RVSM environment and to address all issues 
related to aircraft airworthiness, maintenance, and operations. The 
group has produced guidance material for aircraft and operator 
approval, which ICAO has distributed to civil aviation authorities and 
NAT users. ICAO has planned that the guidance material be incorporated 
in the approval process established by the States.
     Developing the system for monitoring aircraft altitude-
keeping performance. This system is used to observe aircraft 
performance in the vertical plane to determine that the approval 
process is uniformly effective and that the RVSM airspace system is 
safe.
     Evaluating and developing ATC procedures for RVSM, 
conducting simulation studies to assess the effect of RVSM on ATC, and 
developing documents to address ATC issues.
    The NATSPG RVSM implementation program was endorsed by the ICAO 
Limited NAT Regional Air Navigation Meeting held in Portugal in 
November 1992. At that meeting, it was concluded that RVSM 
implementation should be pursued. The FAA concurred with the 
conclusions of the NATSPG on RVSM implementation.
    On August 17, 1993, the FAA held a public meeting to obtain input 
and data that would be considered by the FAA in determining if and how 
to implement reduced vertical separation in appropriate airspace. The 
32 meeting participants included representatives of the aviation 
industry, including manufacturers and air carriers, and unions, as well 
as pilots and government officials. Five members of the public made 
formal statements.
    The ATA supported RVSM, indicating that the FAA should proceed as 
quickly as possible with implementation because of direct economic 
benefit for airlines. A member of the ATA supported the concept and 
indicated that Traffic Alert and Collision Avoidance Systems (TCAS) 
should be included in the system specifications. The speaker indicated 
that, in his analysis, no changes to the TCAS system would be needed to 
implement the reduced vertical separation.
    The Airline Pilots Association (ALPA) supported RVSM, but expressed 
concern that the engineering requirements were so complex that 
continuing compliance could be difficult. Therefore, ALPA emphasized 
that there must be an ongoing effort to collect data on altitude 
keeping performance through monitoring to prevent those not meeting the 
requirements from entering or using RVSM airspace.
    The National Air-Traffic Controllers' Association (NATCA) opposed 
RVSM at that time because of the potential increase in traffic volume 
in RVSM airspace without a corresponding increase in the number of 
controllers. However, the NATCA speaker said the increase in oceanic 
capacity through RVSM implementation should be pursued when the FAA 
fully staffs the air traffic control system and provides adequate 
automation to aid the controllers.
    (In the interim since the August, 1993 public meeting, the FAA 
conducted a series of real time simulations at the FAA Technical 
Center's National Simulation Capability (NSC). Simulations where 
conducted to assist the FAA's Air Traffic organizations in defining 
geographical areas for RVSM transitioning and establishing procedures 
to effect that transition. Controllers, and controllers representing 
NATCA, from New York, Boston and Miami Air Route Traffic Control 
Centers, participated in the simulations. As indicated in the National 
Simulation Capability RVSM Phase I Result Report, August 1995, the 
simulation results indicated that, while interval increases in 
controller workload occurred under RVSM traffic conditions when 
compared with conventional vertical separation minima (2000 feet) 
conditions, the overall controller workload did not increase. High 
interval workload did not interfere with a controller's ability to 
provide service to the aircraft. Based upon the Phase I RVSM simulation 
results, the introduction of RVSM in the New York Oceanic Airspace is 
feasible provided that certain procedures are well defined and agreed 
upon prior to implemention.)
    The National Business Aircraft Association (NBAA) supported the 
reduced vertical separation concept. However, NBAA expressed concern 
over the cost of equipping aircraft to enter RVSM airspace. Also, NBAA 
was concerned that if the RVSM concept was to be considered for the 
Pacific area and domestic airspace, significant expense to operators 
could result from the requirement for all airplanes to be equipped, 
validated, and maintained to RVSM standards. NBAA viewed this as a 
significant long-range cost impact.

Reference Material

    The FAA and other entities studying the issue of RVSM requirements 
have produced a number of studies and reports. The FAA used the 
following documents in the development of this amendment.

     Summary Report of United States Studies on 1,000-Foot 
Vertical Separation Above Flight Level 290 (FAA, July 1988).
     Initial Report on Minimum System Performance Standards 
for 1,000-Foot Vertical Separation Above Flight Level 290 (RTCA SC-
150, November 1984); the report provides information on the 
methodology for evaluating safety, factors influencing vertical 
separation, and strawman system performance standards.
     Minimum System Performance Standards for 1,000-Foot 
Vertical Separation Above Flight Level 290 (Draft 7, RTCA, August 
1990); the FAA concurred with the material developed by RTCA SC-150.
     The Report of RGCSP/6 (ICAO, Montreal, 28 November-15 
December 1988) published in two volumes. Volume 1 summarizes the 
major conclusions reached by the panel and the individual States. 
Volume 2 presents the complete RVSM study reports of the individual 
States:
     European Studies of Vertical Separation Above FL 290--
Summary Report (prepared by the Eurocontrol Vertical Studies 
Subgroup).

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     Summary Report of United States Studies on 1,000-Foot 
Vertical Separation Above Flight Level 290 (prepared by the FAA 
Technical Center and ARINC Research Corporation).
     The Japanese Study on Vertical Separation.
     The Report of the Canadian Mode C Data Collection.
     The Results of Studies on the Reduction of Vertical 
Separation Intervals for USSR Aircraft at Altitudes Above 8,100 m 
(prepared by the USSR).
     Report of RGCSP/7 (Montreal, 30 October-20 November 
1990) containing a draft Manual on Implementation of a 300 M (1,000 
Ft) Vertical Separation Minimum (VSM) Between FL 290 and 410 
Inclusive, approved by the ICAO Air Navigation Commission in 
February 1991 and published as ICAO Document 9574.
     Interim Guidance Material 91-RVSM, ``Approval of 
Aircraft and Operators for Flight in Airspace Above FL 290 Where a 
1,000 Foot Vertical Separation is Applied'' (March 14, 1994). (The 
interim guidance continues to provide recommended procedural steps 
for obtaining FAA approval.)
     AC No. 91-70, ``Oceanic Operations'' (September 6, 
1994).
     Flight Standards Handbook Bulletin for Air 
Transportation (HBAT) ``Approval of Aircraft and Operators for 
Flight in Airspace Above Flight Level 290 Where a 1,000 Foot 
Vertical Separation Minimum is Applied'' (HBAT 97-02).

Related Activity

    The FAA plans to implement RVSM starting in the NAT MNPS airspace 
because of the data and operational controls available for this 
airspace, and because of the operational efficiency problems in that 
airspace. The FAA's groundwork for determining the feasibility of RVSM 
and developing this rule has been carried out in conjunction with the 
NATSPG's plans to implement RVSM in the NAT MNPS Airspace.
    Implementation is occurring in two phases:
1. Verification Phase
    During the verification phase, aircraft have continued to be 
vertically separated by 2,000 feet, and operators and aircraft have 
begun to receive RVSM approval in accordance with the FAA's ``Interim 
Guidance Material'' (91-RVSM).
    The overall objectives of the verification phase are to:
    1. Confirm that the NAT target level of safety (TLS) will continue 
to be met.
    2. Confirm that aircraft approved for RVSM operation demonstrate 
altitude-keeping performance that meets RVSM standards. This will be 
achieved by:
     Identifying and eliminating any causes of out-of-tolerance 
altitude-keeping performance, in general or for specific aircraft 
groups; and
     Monitoring a sample of RVSM-approved aircraft and 
operators that is representative of the total NAT MNPS population.
    3. Verify that operational procedures adopted for RVSM are 
effective and appropriate.
    4. Confirm that the altitude-monitoring program is effective.
    The principal purpose of this phase has been to gain confidence 
that the operational trial phase can begin.
2. Operational Trial Phase
    As the objectives of the system verification phase have been met, 
NATSPG plans to implement RVSM at designated flight levels with 
separation of 1,000 feet on an operational trial basis starting March 
27, 1997 for approximately one year. In the initial phase of 
implementation, the NATSPG plans to implement RVSM only at certain 
flight levels (FL 330 to FL 370). The objectives of the operational 
trial phase are to:
    1. Continue to collect altitude-keeping performance data.
    2. Increase the level of confidence that safety goals are being 
met.
    3. Demonstrate operationally that there are no difficulties with 
RVSM implementation.
    Starting March 27, 1997, aircraft that do not meet the RVSM 
requirements will be excluded from operations at flight levels where 
RVSM is applied. Provided that all requirements continue to be met, at 
the end of the operational trial period, RVSM will be declared fully 
operational.
    To help operators prepare to comply with the requirements of this 
rule, the FAA has prepared two documents, which are available in the 
docket. The first of these documents, distributed at the ICAO meetings 
since April, 1994, is Interim Guidance Material on the Approval of 
Operators/Aircraft for RVSM Operations (91-RVSM). This document 
contains guidance for the approval of aircraft and operators to conduct 
RVSM operations. It is based on the ICAO manual on RVSM. It was 
developed in the NATSPG forum by technical and operational experts from 
the FAA, the European Joint Airworthiness Authorities (JAA), the 
aircraft manufacturers, and pilot associations. The FAA is taking steps 
to publish it as an advisory circular (AC). In the interim, a copy of 
91-RVSM may be obtained by contacting the person identified under FOR 
FURTHER INFORMATION CONTACT.
    The second document is a Flight Standards Handbook Bulletin (HBAT) 
97-02 entitled Approval of Aircraft and Operators for Flight in 
Airspace Above Flight Level 290 Where 1,000 Foot Vertical Separation 
Minimum Is Applied, and has been distributed through Flight Standards 
offices.
    The interim guidance material describes methods of complying with 
the airworthiness approval, maintenance program approval, and 
operations approval requirements in the rule. It discusses timing, 
process, and maintenance and operations material that the operator 
should submit for FAA review and evaluation normally at least 60 days 
before the planned operation in RVSM airspace. Operators under Title 
14, Code of Federal Regulations (14 CFR) part 91 receive FAA approval 
in the form of a letter of authorization, and operators under 14 CFR 
parts 121, 125, and 135 receive operations specifications approval.
    The HBAT contains background information on RVSM, directs 
inspectors to use the Interim Guidance 91-RVSM for operator approval, 
and contains specific direction on issuing operating authority.

Altitude-Keeping Performance

    The FAA, in conjunction with the NATSPG, also has been monitoring 
aircraft altitude-keeping performance. The NATSPG, with industry 
participation, determined that the overall (i.e., accounting for 
equipment and human error) criterion for safety in the NAT region is 
the target level of safety (TLS) of no more than five fatal accidents 
in 1 billion flying hours. The FAA has determined that the appropriate 
method of assessing collision risk is the Reich collision risk model 
(CRM). As noted in AC No. 91-70, ``Oceanic Operations,'' collision risk 
refers to the number of midair accidents likely to occur due to loss of 
separation in a prescribed volume of airspace for a specific number of 
flight hours.
    To ensure that the TLS considered acceptable in the NAT is met, the 
FAA and the NATSPG are monitoring the total vertical error (TVE) and 
the remaining CRM parameters that are critical for safety assessment 
(probability of lateral and longitudinal overlap). TVE is defined as 
the geometric difference between aircraft and flight level altitude. To 
monitor TVE, the FAA and the NATSPG have deployed measurement systems 
that will produce estimates of aircraft and flight level geometric 
altitude. The overall goal of monitoring is to ensure that 
airworthiness, maintenance, and operational approval requirements 
result in required system performance (and level of safety) in the 
flight environment on a continuing basis. Currently, two altitude-
monitoring

[[Page 17484]]

systems are operating: a Global Positioning System (GPS)-based 
monitoring system and a Height monitoring unit (HMU) that uses a Mode C 
multilateration system. Data are currently being collected on both 
systems to determine technical and operational feasibility.
    Collision Risk Methodology (CRM) (including an acceptable level of 
safety) was used to develop the requirements for safe implementation of 
a 1,000 foot vertical separation standard. The level of safety was 
developed using historical data on safety from global sources. One 
precedence used was a period of 100 to 150 years between midair 
collisions. When the NATSPG TLS of 5 accidents in a billion flying 
hours is projected in terms of a calendar year interval between 
accidents, it yields a theoretical interval of approximately 390 years 
between midair collisions. The accepted level of safety is consistent 
with the acceptable level for aircraft hull loss and is based on the 
precedence of extremely improbable events as they relate to system 
safety, the basis for certain requirements in certification regulations 
such as 14 CFR 25.1309. The United States supported the methodology 
used to derive the accepted level of safety for RVSM implementation.
    Following the development of the accepted level of safety, the 
corresponding limits for TVE and altimetry system errors were 
developed. A detailed discussion of the mathematical rationale leading 
to the requirements for safe implementation of RVSM is available in the 
docket.

Current Requirements

    In the Federal Aviation Regulations, 14 CFR 91.179(b)(3) 
establishes the 2,000 ft minimum separation in domestic airspace by 
requiring that flights in uncontrolled airspace at and above FL 290 on 
easterly magnetic courses (zero degrees through 179 degrees) be 
conducted at 4,000 ft intervals, starting at FL 290, (e.g., FL 290, 
330, or 370). West-bound flights (magnetic courses of 180 degrees 
through 359 degrees) must be conducted at 4,000 ft intervals beginning 
at FL 310 (e.g., FL 310, 350, or 390). Flights in controlled airspace 
must be conducted at an altitude assigned by ATC.
    For operations within a foreign country, 14 CFR 91.703 requires 
compliance with that country's regulations. For operations over the 
high seas outside the United States, 14 CFR 91.703 requires that 
aircraft of U.S. registry comply with Annex 2 (Rules of the Air) to the 
Convention on International Civil Aviation. Annex 2, amendment 32, 
effective February 19, 1996, reflects the planned change from 2,000 
feet to 1,000 feet vertical separation for Instrument Flight Rules 
(IFR) traffic between FL 290 and FL 410, based on appropriate airspace 
designation, international agreements, and conformance with specified 
conditions. By this amendment, Annex 2, through amendment 32, is 
incorporated by reference in Sec. 91.703(b).
    Regulatory requirements for operations within the NAT MNPS by U.S.-
registered aircraft are contained in 14 CFR 91.705. The regulation 
states that the aircraft must have approved navigation performance 
capability that meets specified requirements, and that the operator 
have authorization from the Administrator for operations in the NAT 
MNPS.
    The NAT MNPS is addressed in greater detail in appendix C to Part 
91, Operations in the North Atlantic (NAT) Minimum Navigation 
Performance Specifications (MNPS) Airspace. The appendix defines the 
airspace geographically and sets minimum navigation performance 
capability requirements.

General Discussion of the Amendment

    This rule allows operations of civil aircraft of U.S. registration 
outside the U.S. in airspace where a 1,000 foot vertical separation is 
applied, based on improvements in altitude-keeping technology. These 
improvements include:
     Introduction of the air data computer (ADC), which 
provides an automatic means of correcting the known static source error 
of aircraft to improve aircraft altitude measurement capability.
     Development of altimeters with enhanced transducers or 
double aneroids for computing altitude.
    Under this amendment, airspace or routes in which RVSM is applied 
are considered special qualification airspace. Both the operator and 
the specific types of aircraft that the operator intends to use in RVSM 
airspace would have to be approved by the appropriate FAA office before 
the operator conducts flights in RVSM airspace.
    Implementation of a 1,000 foot vertical separation standard above 
FL 290 offers substantial operational benefits to operators, including:
     Greater availability of the most fuel-efficient altitudes. 
In the RVSM environment, aircraft are able to fly closer to their 
optimum altitude at initial level off and through step climbing to the 
optimum altitude during the enroute phase.
     Greater availability of the most time- and fuel-efficient 
tracks and routes (and an increased probability of obtaining these 
tracks and routes). Operators often are not cleared on the track or 
route that was filed due to demand for the optimum routes, and 
resultant traffic congestion on those routes. RVSM allows ATC to 
accommodate a greater number of aircraft on a given track or route. 
More time- and fuel-efficient tracks or routes would therefore be 
available to more aircraft.
     Increased controller flexibility. RVSM gives ATC greater 
flexibility to manage traffic by increasing the number of flight levels 
on each track or route.
     Enhanced safety in the lateral dimension. Studies indicate 
that RVSM produces a wider distribution of aircraft among different 
tracks and altitudes, resulting in less exposure to aircraft at 
adjacent separation standards. RVSM reduces the number of occasions 
when two aircraft pass each other separated by a single separation 
standard (e.g., 60 nm laterally). The benefit to safety is that, should 
an aircraft enter, as a result of gross navigation error, onto an 
adjacent track, and another aircraft is on that track, there is an 
increased probability that the two aircraft would be flying at 
different flight levels.
    This rule amends Sec. 91.703(a)(4) and continues to require that 
operations conducted within airspace designated as MNPS airspace be 
conducted in accordance with Sec. 91.705. The rule also requires that 
operations conducted within airspace designated as Reduced Vertical 
Separation Airspace be conducted in accordance with a new Sec. 91.706.
    Section 91.705 has been edited to delete references to the North 
Atlantic. The revised section also corrects format errors.
    Section 91.706 is added to prescribe the requirements for 
operations conducted in airspace designated as Reduced Vertical 
Separation Minimum Airspace. That section is similar in form to 
Sec. 91.705. It requires that each operator obtain authorization from 
the FAA to operate in airspace designated as RVSM, and requires each 
operator to obtain RVSM approval for their aircraft in accordance with 
appendix G.
    The new appendix G specifies essential aircraft equipment and 
capabilities, including altitude measurement systems; altitude control 
systems; and an altitude alert system. RVSM aircraft are required to 
meet requirements for altimetry system error containment, equipment 
installation, and equipment tolerances. The control systems are 
required to automatically

[[Page 17485]]

control aircraft altitude to within specified limits (in non-turbulent, 
non-gust conditions). The associated alert systems are required to 
alert flightcrews to deviations of more than 300 feet from selected 
altitudes, or 200 feet for aircraft for which application for type 
certification occurs after April 8, 1997.
    Altitude system error (ASE) requirements are prescribed in part 91, 
appendix G, section 2, paragraph (e). The ASE that aircraft groups are 
required to exhibit in service for acceptable aircraft altitude-keeping 
performance to be achieved in the full RVSM flight envelope is:
    The mean ASE of an aircraft group must not exceed 120 feet and the 
sum of mean ASE plus three standard deviations of ASE must not exceed 
245 feet.
    On the basis of studies documented in ICAO Document 9536, Volume 2, 
a margin was established between the ASE to be exhibited in service and 
the ASE criteria used for initial approval to allow for some 
degradation with increasing aircraft age. Thus, for initial aircraft 
approval, the following ASE requirements are established in the basic 
envelope (as defined below):
    The mean ASE of the group must not exceed 80 feet, and the sum of 
ASE for the aircraft group plus three standard deviations must not 
exceed 200 feet.
    For the purpose of approving in-service aircraft, the FAA divides 
the flight envelope into two parts to provide a reasonable method for 
applying the above criteria to currently type-certificated aircraft. 
The Basic RVSM flight envelope (see part 91, appendix G, section 1) 
represents the aircraft speeds, altitudes and weights at which the 
majority of aircraft operations are conducted. The Full RVSM flight 
envelope also includes portions of the operating flight envelope in 
which aircraft operate less frequently. The values of 80 feet for mean 
ASE and 200 feet for mean ASE plus three standard deviations of ASE 
must be met in the Basic RVSM flight envelope. The values of 120 feet 
for mean ASE and 245 feet for mean ASE plus three standard deviations 
must be met in the Full RVSM flight envelope.
    For RVSM approval of aircraft for which a type certificate is 
requested after April 9, 1997, however, the FAA has determined that it 
is not necessary to continue designating two flight envelopes (i.e., 
Basic and Full flight envelopes). With values of 80 feet for mean ASE 
and 200 feet for mean ASE plus three standard deviations for ASE 
established during the design phase, the FAA has determined that those 
values can also be achieved throughout the Full RVSM flight envelope.
    The ASE criteria for group aircraft will not be applied to non-
group aircraft, because with non-group aircraft there is no data with 
which to measure airframe to airframe variability. Therefore, a single 
ASE value would be established to control the simple sum of altimetry 
errors. To control the overall population distribution, this limit 
would be set at a value less than that for group aircraft.
    The new appendix G also provides for limited deviations to the 
operator and aircraft approval requirements. To accomplish this, the 
appendix states that an operator's request should normally be submitted 
at least 48 hours in advance of the proposed flight except under 
mitigating circumstances, so that ATC could then determine if proper 
separation could be provided without interference with normal RVSM 
operations. As with current appendix C to part 91, such deviations are 
considered as exceptions, not normal operations. For example, the 
operations envisioned that could be conducted in deviation from the 
RVSM requirements are the occasional part 91 flight in a business jet, 
or a maintenance ferry flight of a part 121 certificate holder's 
aircraft for the purpose of performing maintenance and returning the 
aircraft to RVSM-approved status.
    Under this amendment, the new appendix G designates, in Section 8, 
those areas in which RVSM may be applied. Initially, as previously 
stated, RVSM will be applied only at designated flight levels in NAT 
MNPS airspace (e.g., FL 330 to FL 370). However, the appendix is 
otherwise structured in a generic format so that other airspace could 
be added to the designation when RVSM is expanded. By reviewing Section 
8, operators are provided notification of areas where RVSM may be 
applied. (Operations still have the Annex 2 requirements to determine 
route requirements during preflight.)
    NATSPG has agreed to change the floor and ceiling of MNPS airspace 
to FL 285 and FL 420. This change will enable the application of RVSM 
between FL 290 and FL 410, inclusive. The FAA does not consider this to 
be a substantive change.
    The new appendix generally defines RVSM airspace as any airspace 
between FL 290 and FL 410 (inclusive) where aircraft are to be 
separated by a minimum of 1,000 feet vertically. The appendix also 
specifies that operators receive approval for RVSM operations either 
through operations specifications or a Letter of Authorization, as 
appropriate. Applicants for operation in RVSM airspace are required to 
submit supporting material for aircraft approval, including information 
on compliance with the performance and hardware requirements and on the 
operator's maintenance program, in connection with meeting RVSM minimum 
performance requirements. Operators are also required to implement 
policies and procedures related to RVSM operations and to show that 
their pilots have necessary knowledge of those policies and procedures.
    Specific guidance on how to meet the requirements is available in 
Interim Guidance Material 91-RVSM, which addresses various aspects of 
RVSM requirements, including maintenance and operations programs. 
Operators can obtain authorization for RVSM from their local Flight 
Standards District Office (FSDO) or Certificate Management Office. 
Approval of aircraft may be given for aircraft groups or for individual 
aircraft. In the former case, the FAA expects that operators would need 
to enlist the assistance of the aircraft manufacturers to develop the 
necessary data on the aircraft group. In the latter case, the operator 
would work with the FAA to determine the accuracy of the altitude-
keeping equipment on the individual aircraft.
    This amendment results in more stringent vertical navigation 
standards in oceanic airspace; the standards will be applied in other 
airspace above FL 290 as they are designated as RVSM airspace in the 
future. In NAT MNPS airspace, aircraft and operators that do not meet 
the vertical navigation requirements of RVSM will be accommodated in 4 
ways--First, RVSM will be implemented in stages. In Stage 1, RVSM 
approval will be required when operating between FL 33 to FL 370 
inclusive. Unapproved operators will have the option of flying at FL 
310 and below or FL 390 and above. The staged implementation plan was 
adopted to give operators more time and flexibility in their planning 
to gain RVSM approval (Note: NATSPG will evaluate user needs before 
implementing a second stage that applies RVSM requirements to other 
flight levels.). Second, unapproved operators will be allowed to climb 
or descend in MNPS airspace through flight levels where RVSM is applied 
to operate at FL's where RVSM is not applied. Third, the operator may 
be authorized to deviate from RVSM requirements in accordance with the 
provisions of Appendix G, Section 5. Though it is not intended to be 
the routine mode of operation, this section

[[Page 17486]]

does enable an operator that has not been RVSN approved (or an aircraft 
with an RVSM required system temporarily inoperative) to fly in MNPS 
airspace where RVSM is applied provided request is made in advance and 
ATC determines that appropriate separation can be applied without 
imposing a burden on other operators. And fourth, when RVSM is applied 
to all flight levels in MNPS airspace (FL 290 to 410 inclusive), the 
operator not wishing to gain RVSM approval will retain the option of 
crossing the North Atlantic at FL's above or below airspace where RVSM 
requirements apply. Such an operator will be able to fly at FL 280 and 
below or FL 430 and above. The FAA has determined that these are 
reasonable and adequate means to accommodate the transition to RVSM 
requirements, particularly for general aviation operators.
    The Interim Guidance is intended to be applicable for RVSM aircraft 
and operator approval in continental, oceanic, and remote airspace. The 
FAA expects that RVSM eventually will be applied in other airspace, 
including the Pacific region, Europe, and eventually even U.S. 
airspace. The rule establishes requirements for operation of U.S. 
registered aircraft outside the U.S. in any airspace designated for 
RVSM; it specifically establishes that the NAT MNPS airspace is an area 
where RVSM may be applied.

Need for Immediate Adoption

    This action is a product of international agreements. It is the 
implementation of a joint, ongoing action started in 1988 with the 
member States of ICAO. The international aviation community is prepared 
to and will begin operational testing of the RVSM procedures in certain 
altitudes on March 27, 1997.
    The United States, as a member of ICAO, has an international 
commitment to participate in this action. Arriving air traffic, having 
departed Europe and separated at RVSM altitudes, as a practical matter, 
cannot arrive in oceanic airspace controlled by the United States, all 
needing to be reassigned to a pre-RVSM separation altitude. Unless this 
rule is implemented by March 27, 1997, to avoid a significant safety 
problem, there would have to be major delays for westbound NAT traffic 
in airspace the FAA does not control.
    Additionally, U.S. operators will incur an economic disadvantage 
compared to their European competitors, if they are unable to utilize 
the benefits gained from operating at RVSM altitudes beginning on March 
27, 1997,
    Because of the imminent beginning of operational testing by all 
countries involved, good cause exists for making this final rule 
effective immediately.

Regulatory Evaluation Summary

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 directs that each Federal agency 
shall 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 requires agencies to analyze the 
economic effect of regulatory changes on small entities. Third, the 
Office of Management and Budget directs agencies to assess the effect 
of regulatory changes on international trade. In conducting these 
analyses, the FAA has determined that this rule: (1) generates benefits 
that justify its costs and is not ``a significant regulatory action'' 
as defined in the Executive Order; (2) is significant as defined in 
Department of Transportation's Regulatory Policies and Procedures; (3) 
does not have a significant impact on a substantial number of small 
entities; and (4) does not constitute a barrier to international trade. 
These analyses, available in the docket are summarized below.
    This rule establishes a new Federal Aviation Regulations (FAR) 
section that allows the vertical separation minimum from 2,000 feet to 
1,000 feet between FL 290 and FL 410 to be reduced in certain 
designated airspace. This action is intended to increase the number of 
available flight levels, enhance airspace capacity, permit operators to 
fly more fuel/time efficient tracks and altitudes, and enhance air 
traffic controller flexibility by increasing the number of available 
flight levels, while maintaining an equivalent level of safety.
    Assuming that operators with the capability of operating above FL 
410 would do so in lieu of obtaining RVSM approval, the FAA estimates 
that this rule costs U.S. operators $28.1 million in constant 1995 
dollars for the fifteen-year time period 1996-2010 or $20.4 million 
discounted. Benefits begin accruing in 1997. Benefits, based on fuel 
savings for the commercial aircraft fleet over the years 1997 to 2010, 
are estimated to be $35.8 million undiscounted in constant 1995 dollars 
or discounted at $24.0 million. The other benefits of implementing RVSM 
are: (1) availability of added tracks; (2) increased controller 
flexibility to clear aircraft for efficient step (enroute) climbs; and 
(3) increased controller flexibility to route aircraft to appropriate 
tracks. Therefore, based on a quantitative and qualitative evaluation 
of this action, the FAA believes that the amendment is cost-beneficial.

Regulatory Flexibility Act

    The FAA has determined that these amendments do not significantly 
affect a substantial number of small entities.

International Trade Impact Analysis

    This amendment does not affect the importation of foreign products 
or services into the United States or the exportation of U.S. products 
or services to foreign countries.

Federalism Implications

    This rule will not have substantial direct effects 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. Therefore, in accordance with Executive Order 
12612, it is determined that this amendment does not have sufficient 
federalism implications to warrant the preparation of a Federalism 
Assessment.

Paperwork Reduction Act of 1995

    The reporting and recordkeeping requirements associated with this 
rule remain the same as under the current rules and have previously 
been approved by the Office of Management and Budget under the 
provisions of the Paperwork Reduction Act of 1980 (Pub. L. 96-511) and 
have been assigned OMB Control Numbers 2120-0026. The FAA believes that 
this rule does not impose any additional recordkeeping or reporting 
requirements.

Unfunded Mandates Reform Act of 1995

    The FAA has determined that the requirements of Title II of the 
Unfunded Mandates Reform Act of 1995 do not apply to this rulemaking.

International Civil Aviation Organization and Joint Aviation 
Regulations

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation Organization (ICAO), it is FAA policy to 
comply with ICAO Standards and Recommended Practices (SARP) to maximum 
extent practicable. The operator and aircraft approval process was 
developed jointly by the FAA and the JAA under the auspices of NATSPG. 
The FAA has determined that this amendment does not present any 
difference.

[[Page 17487]]

Conclusion

    For the reasons discussed in the Preamble, and based on the 
findings in the Regulatory Flexibility Determination and the 
International Trade Impact Analysis, the FAA has determined that this 
rule is not a ``significant regulatory action'' under Executive Order 
12866. In addition, the FAA certifies that this regulation does not 
have a significant economic impact, positive or negative, on a 
substantial number of small entities under the criteria of the 
Regulatory Flexibility Act of 1990. This amendment is considered 
significant under Order DOT 2100.5, Policies and Procedures for 
Simplification, Analysis, and Review of Regulations due to the 
significant international ramifications of this rule. A regulatory 
evaluation of the regulation, including a Regulatory Flexibility 
Determination and International Trade Impact Analysis, are available in 
the docket. A copy may be obtained by contacting the person identified 
under FOR FURTHER INFORMATION CONTACT.

List of Subjects in 14 CFR Part 91

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

The Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration amends part 91 of Title 14 of the Code of Federal 
Regulations (14 CFR part 91) 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), 40103, 40113, 40120, 44101, 44111, 
44701, 44709, 44711, 44712, 44715, 44716, 44717, 44722, 46306, 
46315, 46316, 46502, 46504, 46506-46507, 47122, 47508, 47528-47531.

    2. Section 91.703 is amended by revising paragraphs (a)(4) and (b) 
to read as follows:


Sec. 91.703  Operations of civil aircraft of U.S. registry outside of 
the United States.

    (a)* * *
    (4) When operating within airspace designated as Minimum Navigation 
Performance Specifications (MNPS) airspace, comply with Sec. 91.705. 
When operating within airspace designated as Reduced Vertical 
Separation Minimum (RVSM) airspace, comply with Sec. 91.706.
    (b) Annex 2 to the Convention on International Civil Aviation, 
Ninth Edition--July 1990, with Amendments through Amendment 32 
effective February 19, 1996, to which reference is made in this part, 
is incorporated into this part and made a part hereof as provided in 5 
U.S.C. Sec. 552 and pursuant to 1 CFR part 51. Annex 2 (including a 
complete historic file of changes thereto) is available for public 
inspection at the Rules Docket, AGC-200, Federal Aviation 
Administration, 800 Independence Avenue SW., Washington, DC 20591; or 
at the Office of the Federal Register, 800 North Capitol Street, NW., 
Suite 700, Washington, DC. In addition, Annex 2 may be purchased from 
the International Civil Aviation Organization (Attention: Distribution 
Officer), P.O. Box 400, Succursale, Place de L'Aviation Internationale, 
1000 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2R2.
    3. Section 91.705 is revised to read as follows:


Sec. 91.705  Operations within airspace designated as Minimum 
Navigation Performance Specification Airspace.

    (a) Except as provided in paragraph (b) of this section, no person 
may operate a civil aircraft of U.S. registry in airspace designated as 
Minimum Navigation Performance Specifications airspace unless--
    (1) The aircraft has approved navigation performance capability 
that complies with the requirements of appendix C of this part; and
    (2) The operator is authorized by the Administrator to perform such 
operations.
    (b) The Administrator may authorize a deviation from the 
requirements of this section in accordance with Section 3 of appendix C 
to this part.
    4. New Sec. 91.706 is added to read as follows:


Sec. 91.706  Operations within airspace designed as Reduced Vertical 
Separation Minimum Airspace.

    (a) Except as provided in paragraph (b) of this section, no person 
may operate a civil aircraft of U.S. registry in airspace designated as 
Reduced Vertical Separation Minimum (RVSM) airspace unless:
    (1) The operator and the operator's aircraft comply with the 
requirements of appendix G of this part; and
    (2) The operator is authorized by the Administrator to conduct such 
operations.
    (b) The Administrator may authorize a deviation from the 
requirements of this section in accordance with Section 5 of appendix G 
to this part.
    5. Section 1 of Appendix C to Part 91 is amended by removing the 
flight levels ``FL 275'' and ``FL 400'' cited in the first sentence and 
replacing them with ``FL 285'' ``FL 420'' respectively.
    6. A new appendix G is added to read as follows:

Appendix G to Part 91--Operations in Reduced Vertical Separation 
Minimum (RVSM) Airspace

Section 1. Definitions

    Reduced Vertical Separation Minimum (RVSM) Airspace. Within RVSM 
airspace, air traffic control (ATC) separates aircraft by a minimum 
of 1,000 feet vertically between flight level (FL) 290 and FL 410 
inclusive. RVSM airspace is special qualification airspace; the 
operator and the aircraft used by the operator must be approved by 
the Administrator. Air-traffic control notifies operators of RVSM by 
providing route planing information. Section 8 of this appendix 
identifies airspace where RVSM may be applied.
    RVSM Group Aircraft. Aircraft within a group of aircraft, 
approved as a group by the Administrator, in which each of the 
aircraft satisfy each of the following:
    (a) The aircraft have been manufactured to the same design, and 
have been approved under the same type certificate, amended type 
certificate, or supplemental type certificate.
    (b) The static system of each aircraft is installed in a manner 
and position that is the same as those of the other aircraft in the 
group. The same static source error correction is incorporated in 
each aircraft of the group.
    (c) The avionics units installed in each aircraft to meet the 
minimum RVSM equipment requirements of this appendix are:
    (1) Manufactured to the same manufacturer specification and have 
the same part number; or
    (2) Of a different manufacturer or part number, if the applicant 
demonstrates that the equipment provides equivalent system 
performance.
    RVSM Nongroup Aircraft. An aircraft that is approved for RVSM 
operations as an individual aircraft.
    RVSM Flight envelope. An RVSM flight envelope includes the range 
of Mach number, weight divided by atmospheric pressure ratio, and 
altitudes over which an aircraft is approved to be operated in 
cruising flight within RVSM airspace. RVSM flight envelopes are 
defined as follows:
    (a) The full RVSM flight envelope is bounded as follows:
    (1) The altitude flight envelope extends from FL 290 upward to 
the lowest altitude of the following:
    (i) FL 410 (the RVSM altitude limit);
    (ii) The maximum certificated altitude for the aircraft; or
    (iii) The altitude limited by cruise thrust, buffet, or other 
flight limitations.
    (2) The airspeed flight envelope extends:
    (i) From the airspeed of the slats/flaps-up maximum endurance 
(holding) airspeed, or the maneuvering airspeed, whichever is lower;
    (ii) To the maximum operating airspeed (Vmo/Mmo), or 
airspeed limited by cruise thrust buffet, or other flight 
limitations, whichever is lower.

[[Page 17488]]

    (3) All permissible gross weights within the flight envelopes 
defined in paragraphs (1) and (2) of this definition.
    (b) The basic RVSM flight envelope is the same as the full RVSM 
flight envelope except that the airspeed flight envelope extends:
    (1) From the airspeed of the slats/flaps-up maximum endurance 
(holding) airspeed, or the maneuver airspeed, whichever is lower;
    (2) To the upper Mach/airspeed boundary defined for the full 
RVSM flight envelope, or a specified lower value not less than the 
long-range cruise Mach number plus .04 Mach, unless further limited 
by available cruise thrust, buffet, or other flight limitations.

Section 2. Aircraft Approval

    (a) An operator may be authorized to conduct RVSM operations if 
the Administrator finds that its aircraft comply with this section.
    (b) The applicant for authorization shall submit the appropriate 
data package for aircraft approval. The package must consist of at 
least the following:
    (1) An identification of the RVSM aircraft group or the nongroup 
aircraft;
    (2) A definition of the RVSM flight envelopes applicable to the 
subject aircraft;
    (3) Documentation that establishes compliance with the 
applicable RVSM aircraft requirements of this section; and
    (4) The conformity tests used to ensure that aircraft approved 
with the data package meet the RVSM aircraft requirements.
    (c) Altitude-keeping equipment: All aircraft. To approve an 
aircraft group or a nongroup aircraft, the Administrator must find 
that the aircraft meets the following requirements:
    (1) The aircraft must be equipped with two operational 
independent altitude measurement systems.
    (2) The aircraft must be equipped with at least one automatic 
altitude control system that controls the aircraft altitude--
    (i) Within a tolerance band of 65 feet about an 
acquired altitude when the aircraft is operated in straight and 
level flight under nonturbulent, nongust conditions; or
    (ii) Within a tolerance band of 130 feet under 
nonturbulent, nongust conditions for aircraft for which application 
for type certification occurred on or before April 9, 1997 that are 
equipped with an automatic altitude control system with flight 
management/performance system inputs.
    (3) The aircraft must be equipped with an altitude alert system 
that signals an alert when the altitude displayed to the flight crew 
deviates from the selected altitude by more than:
    (i) 300 feet for aircraft for which application for 
type certification was made on or before April 9, 1997; or
    (ii) 200 feet for aircraft for which application for 
type certification is made after April 9, 1997.
    (d) Altimetry system error containment: Group aircraft for which 
application for type certification was made on or before April 9, 
1997. To approve group aircraft for which application for type 
certification was made on or before April 9, 1997, the Administrator 
must find that the altimetry system error (ASE) is contained as 
follows:
    (1) At the point in the basic RVSM flight envelope where mean 
ASE reaches its largest absolute value, the absolute value may not 
exceed 80 feet.
    (2) At the point in the basic RVSM flight envelope where mean 
ASE plus three standard deviations reaches its largest absolute 
value, the absolute value may not exceed 200 feet.
    (3) At the point in the full RVSM flight envelope where mean ASE 
reaches its largest absolute value, the absolute value may not 
exceed 120 feet.
    (4) At the point in the full RVSM flight envelope where mean ASE 
plus three standard deviations reaches its largest absolute value, 
the absolute value may not exceed 245 feet.
    (5) Necessary operating restrictions. If the applicant 
demonstrates that its aircraft otherwise comply with the ASE 
containment requirements, the Administrator may establish an 
operating restriction on that applicant's aircraft to restrict the 
aircraft from operating in areas of the basic RVSM flight envelope 
where the absolute value of mean ASE exceeds 80 feet, and/or the 
absolute value of mean ASE plus three standard deviations exceeds 
200 feet; or from operating in areas of the full RVSM flight 
envelope where the absolute value of the mean ASE exceeds 120 feet 
and/or the absolute value of the mean ASE plus three standard 
deviations exceeds 245 feet.
    (e) Altimetry system error containment: Group aircraft for which 
application for type certification is made after April 9, 1997. To 
approve group aircraft for which application for type certification 
is made after April 9, 1997, the Administrator must find that the 
altimetry system error (ASE) is contained as follows:
    (1) At the point in the full RVSM flight envelope where mean ASE 
reaches its largest absolute value, the absolute value may not 
exceed 80 feet.
    (2) At the point in the full RVSM flight envelope where mean ASE 
plus three standard deviations reaches its largest absolute value, 
the absolute value may not exceed 200 feet.
    (f) Altimetry system error containment: Nongroup aircraft. To 
approve a nongroup aircraft, the Administrator must find that the 
altimetry system error (ASE) is contained as follows:
    (1) For each condition in the basic RVSM flight envelope, the 
largest combined absolute value for residual static source error 
plus the avionics error may not exceed 160 feet.
    (2) For each condition in the full RVSM flight envelope, the 
largest combined absolute value for residual static source error 
plus the avionics error may not exceed 200 feet.
    (g) If the Administrator finds that the applicant's aircraft 
comply with this section, the Administrator notifies the applicant 
in writing.

Section 3. Operator Authorization

    (a) Authority for an operator to conduct flight in airspace 
where RVSM is applied is issued in operations specifications or a 
Letter of Authorization, as appropriate. To issue an RVSM 
authorization, the Administrator must find that the operator's 
aircraft have been approved in accordance with Section 2 of this 
appendix and that the operator complies with this section.
    (b) An applicant for authorization to operate within RVSM 
airspace shall apply in a form and manner prescribed by the 
Administrator. The application must include the following:
    (1) An approved RVSM maintenance program outlining procedures to 
maintain RVSM aircraft in accordance with the requirements of this 
appendix. Each program must contain the following:
    (i) Periodic inspections, functional flight tests, and 
maintenance and inspection procedures, with acceptable maintenance 
practices, for ensuring continued compliance with the RVSM aircraft 
requirements.
    (ii) A quality assurance program for ensuring continuing 
accuracy and reliability of test equipment used for testing aircraft 
to determine compliance with the RVSM aircraft requirements.
    (iii) Procedures for returning noncompliant aircraft to service.
    (2) For an applicant who operates under part 121 or 135, initial 
and recurring pilot training requirements.
    (3) Policies and Procedures. An applicant who operates under 
part 121 or 135 shall submit RVSM policies and procedures that will 
enable it to conduct RVSM operations safely.
    (c) Validation and Demonstration. In a manner prescribed by the 
Administrator, the operator must provide evidence that:
    (1) It is capable to operate and maintain each aircraft or 
aircraft group for which it applies for approval to operate in RVSM 
airspace; and
    (2) Each pilot has an adequate knowledge of RVSM requirements, 
policies, and procedures.

Section 4. RVSM Operations

    (a) Each person requesting a clearance to operate within RVSM 
airspace shall correctly annotate the flight plan filed with air 
traffic control with the status of the operator and aircraft with 
regard to RVSM approval. Each operator shall verify RVSM 
applicability for the flight planned route through the appropriate 
flight planning information sources.
    (b) No person may show, on the flight plan filed with air 
traffic control, an operator or aircraft as approved for RVSM 
operations, or operate on a route or in an area where RVSM approval 
is required, unless:
    (1) The operator is authorized by the Administrator to perform 
such operations; and
    (2) The aircraft has been approved and complies with the 
requirements of Section 2 of this appendix.

Section 5. Deviation Authority Approval

    The Administrator may authorize an aircraft operator to deviate 
from the requirements of Sec. 91.706 for a specific flight in RVSM 
airspace if that operator has not been approved in accordance with 
Section 3 of this appendix, and if:
    (2) The operator submits an appropriate request with the air 
traffic control center

[[Page 17489]]

controlling the airspace, (request should be made at least 48 hours 
in advance of the operation unless prevented by exceptional 
circumstances); and
    (b) At the time of filing the flight plan for that flight, ATC 
determines that the aircraft may be provided appropriate separation 
and that the flight will not interfere with, or impose a burden on, 
the operations of operators who have been approved for RVSM 
operations in accordance with Section 3 of this appendix.

Section 6. Reporting Altitude-Keeping Errors

    Each operator shall report to the Administrator each event in 
which the operator's aircraft has exhibited the following altitude-
keeping performance:
    (a) Total vertical error of 300 feet or more;
    (b) Altimetry system error of 245 feet or more; or
    (c) Assigned altitude deviation of 300 feet or more.

Section 7. Removal or Amendment of Authority

    The Administrator may amend operations specifications to revoke 
or restrict an RVSM authorization, or may revoke or restrict an RVSM 
letter of authorization, if the Administrator determines that the 
operator is not complying, or is unable to comply, with this 
appendix or subpart H of this part. Examples of reasons for 
amendment, revocation, or restriction include, but are not limited 
to, an operator's:
    (a) Committing one or more altitude-keeping errors in RVSM 
airspace;
    (b) Failing to make an effective and timely response to identify 
and correct an altitude-keeping error; or
    (c) Failing to report an altitude-keeping error.

Section 8. Airspace Designation

    RVSM may be applied in the following ICAO Flight Information 
Regions (FIR's): New York Oceanic, Gander Oceanic, Sondrestrom FIR, 
Reykjavik Oceanic, Shanwick Oceanic, and Santa Maria Oceanic.
    RVSM may be effective in the Minimum Navigation Performance 
Specification (MNPS) airspace with the NAT. The MNPS airspace within 
the NAT is defined by the volume of airspace FL 285 and FL 420 
extending between latitude 27 degrees north and the North Pole, 
bounded in the east by the eastern boundaries of control areas Santa 
Maria Oceanic, Shanwick Oceanic, and Reykjavik Oceanic and in the 
west by the western boundaries of control areas Reykjavik Oceanic, 
Gander Oceanic, and New York Oceanic, excluding the areas west of 60 
degrees west and south of 38 degrees 30 minutes north.

    Issued in Washington, DC, on March 27, 1997.
Barry L. Valentine,
Acting Administrator.
[FR Doc. 97-8367 Filed 4-8-97; 8:45 am]
BILLING CODE 4910-13-M