17480 Federal Register / Vol. 62, No. 68 / Wednesday, April 9, 1997 / Rules and Regulations

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.

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: 9–NPRM–

CMTS@faa.dot.gov. 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 preRVSM 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/suldocs 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
Federal Register / Vol. 62, No. 68 / Wednesday, April 9, 1997 / Rules and Regulations 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 altitudekeeping 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 altitudekeeping 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
17482 Federal Register / Vol. 62, No. 68 / Wednesday, April 9, 1997 / Rules and Regulations

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).
Federal Register / Vol. 62, No. 68 / Wednesday, April 9, 1997 / Rules and Regulations 17483

• 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 altitudekeeping performance that meets RVSM

standards. This will be achieved by:

• Identifying and eliminating any

causes of out-of-tolerance altitudekeeping performance, in general or for

specific aircraft groups; and

• Monitoring a sample of RVSMapproved 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 altitudemonitoring 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
17484 Federal Register / Vol. 62, No. 68 / Wednesday, April 9, 1997 / Rules and Regulations

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 § 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 fuelefficient 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 § 91.703(a)(4) and

continues to require that operations

conducted within airspace designated as

MNPS airspace be conducted in

accordance with § 91.705. The rule also

requires that operations conducted

within airspace designated as Reduced

Vertical Separation Airspace be

conducted in accordance with a new

§ 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 § 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
Federal Register / Vol. 62, No. 68 / Wednesday, April 9, 1997 / Rules and Regulations 17485

control aircraft altitude to within

specified limits (in non-turbulent, nongust 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 inservice aircraft, the FAA divides the

flight envelope into two parts to provide

a reasonable method for applying the

above criteria to currently typecertificated 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
17486 Federal Register / Vol. 62, No. 68 / Wednesday, April 9, 1997 / Rules and Regulations

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

§ 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 § 91.705. When

operating within airspace designated as

Reduced Vertical Separation Minimum

(RVSM) airspace, comply with § 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. § 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:

§ 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 § 91.706 is added to read as

follows:

§ 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.
17488 Federal Register / Vol. 62, No. 68 / Wednesday, April 9, 1997 / Rules and Regulations

(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 § 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
Federal Register / Vol. 62, No. 68 / Wednesday, April 9, 1997 / Rules and Regulations 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 altitudekeeping errors in RVSM airspace;

(b) Failing to make an effective and timely

response to identify and correct an altitudekeeping 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]

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