Reduced Vertical Separation Minimum Operations

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