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, Tel: (202) 267-3734.
SUPPLEMENTARY INFORMATION: Substantive comments are 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 (Tel: 703-321-3339), the Federal Register's
electronic bulletin board service (Tel: 202-512-1661), or the FAA's Aviation
Rulemaking Advisory Committee Bulletin Board Service (Tel: 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.
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 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.
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 flight-crews 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:
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:
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 implementation.)
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.
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.
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:
The principal purpose of this phase has been to
gain confidence that the operational trial phase can begin.
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.
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 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.
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.
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:
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:
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 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 nongroup
aircraft, because with nongroup 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 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.
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.
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.
The FAA has determined that these amendments do not significantly affect a
substantial number of small entities.
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.
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.
The reporting and record-keeping 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 record-keeping or reporting requirements.
The FAA has determined that the requirements of Title II of the Unfunded
Mandates Reform Act of 1995 do not apply to this rulemaking.
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.
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.
Air-traffic control, Aircraft, Airmen, Airports, Aviation safety, Reporting
and record-keeping requirements.
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
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:
3.
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.
4.
The
airspeed flight envelope extends:
.
From
the airspeed of the slats/flaps-up maximum endurance (holding) airspeed, or the
maneuvering airspeed, whichever is lower;
i.
To
the maximum operating airspeed (Vmo/Mmo), or airspeed limited by cruise thrust
buffet, or other flight limitations, whichever is lower.
5.
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.
(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:
6.
An
identification of the RVSM aircraft group or the nongroup aircraft;
7.
A
definition of the RVSM flight envelopes applicable to the subject aircraft;
8.
Documentation
that establishes compliance with the applicable RVSM aircraft requirements of
this section; and
9.
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:
10.
The
aircraft must be equipped with two operational independent altitude measurement
systems.
11.
The
aircraft must be equipped with at least one automatic altitude control system
that controls the aircraft altitude—
.
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
i.
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.
12.
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:
.
±300
feet for aircraft for which application for type certification was made on or
before April 9, 1997; or
i.
±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:
13.
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.
14.
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.
15.
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.
16.
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.
17.
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:
18.
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.
19.
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:
20.
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.
21.
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.
(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:
22.
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:
.
Periodic
inspections, functional flight tests, and maintenance and inspection
procedures, with acceptable maintenance practices, for ensuring continued
compliance with the RVSM aircraft requirements.
i.
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.
ii.
Procedures
for returning noncompliant aircraft to service.
23.
For
an applicant who operates under part 121 or 135, initial and recurring pilot
training requirements.
24.
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:
25.
It
is capable to operate and maintain each aircraft or aircraft group for which it
applies for approval to operate in RVSM airspace; and
26.
Each
pilot has an adequate knowledge of RVSM requirements, policies, and procedures.
(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:
27.
The
operator is authorized by the Administrator to perform such operations; and
28.
The
aircraft has been approved and complies with the requirements of Section 2 of
this appendix.
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:
(a) The operator submits an appropriate request
with the air traffic control center 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.
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.
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.
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