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Reduced Vertical Separation Minimums

Introduction:

  • Reduced Vertical Separation Minimum (RVSM) was mandated by the FAA to allow for the heavy flow of traffic
  • In addition to reorganizing airspace, it requires operators and aircraft to have received RVSM authorization from a responsible civil aviation authority
Instrument Flying Handbook. Figure 3-9, Increase in Aircraft Permitted Between FL 180 and FL 410
Figure 1: Instrument Flying Handbook, Increase in Aircraft Permitted Between FL 180 and FL 410

RVSM Applicability:

  • RVSM applies to airspace over the lower 48 states, Alaska, Atlantic, and Gulf of Mexico High Offshore Airspace and airspace in the San Juan FIR where VHF or UHF voice Direct Controller-Pilot Communication (DCPC) is normally available
    • A chart showing the location of offshore airspace is posted on the Domestic U.S. RVSM (DRVSM) Webpage
  • Policies, guidance and direction for RVSM operations in oceanic airspace where VHF or UHF voice DCPC is not available and the airspace of other countries are posted on the FAA "RVSM Documentation" Webpage

RVSM Mandate:

  • At 0901 UTC on January 20, 2005, RVSM was mandated
  • Spanning from FL290 to 410 (inclusive)
  • On the same time and date, RVSM was also introduced into the adjoining airspace of Canada and Mexico to provide seamless environment for aircraft transferring those borders
    • In addition, RVSM was implemented on the same date in the Caribbean and South American regions

RVSM Authorization:

  • In accordance with FAR 91.180, with only limited exceptions, prior to operating in RVSM airspace, operators and aircraft must have received RVSM authorization from a responsible civil aviation authority
    • If the operator or aircraft or both have not been authorized for RVSM operations, the aircraft will be referred to as a "non-RVSM" aircraft
  • ATC provides accommodations of non-RVSM aircraft flown by the DOD, Air Ambulance (MEDEVAC) operations, foreign State governments, and aircraft flown for certification and development
  • ATC provides accommodations for non-RVSM aircraft climbing and descending through RVSM airspace to/from flight levels above RVSM

Benefits of RVSM:

  • Enhances ATC flexibility, mitigates conflict points, enhances sector throughput, reduces controller workload, and enables crossing traffic
  • Operators gain fuel savings and operating efficiency benefits by flying at more fuel efficient flight levels and on more user preferred routings

Flight Level Orientation Scheme

  • Altitude assignments for direction of flight follow a scheme of odd altitude assignments for magnetic courses 000-179° and even altitudes for magnetic courses 180-359° for flights up to and including FL410

Approval Policy/Procedures, RVSM Monitoring and Databases

  • RVSM Authority:

    • FAR 91.180 applies to RVSM operations within the U.S.
    • FAR 91.706 applies to RVSM operations outside the U.S.
    • Both sections require that the operator obtain authorization prior to operating in RVSM airspace
    • FAR 91.180 requires that, prior to conducting RVSM operations within the U.S., the operator obtain authorization from the FAA or from the responsible authority, as appropriate
    • In addition, it requires that the operator and the operator’s aircraft comply with the standards of 14 CFR Part 91 Appendix G (Operations in RVSM Airspace)
  • Sources of Information

    • The FAA RVSM Website Homepage can be accessed at: http://www.faa.gov/about/office_org/ headquarters_offices/ato/service_units/enroute/ rvsm/
    • The "RVSM Documentation" and "Domestic RVSM" web pages are linked to the RVSM Homepage
    • "RVSM Documentation" contains guidance and direction for an operator to obtain aircraft and operator approval to conduct RVSM operations
    • It provides information for DRVSM and oceanic and international RVSM airspace
    • It is recommended that operators planning to operate in Domestic U.S. RVSM airspace first review the following documents to orient themselves to the approval process
      1. Under "Area of Operations Specific Information," the document, "Basic Operator Information on DRVSM Programs," provides an overview of the DRVSM program and the related aircraft and operator approval programs
      2. In the “Getting Started” section, review the "RVSM Approval Checklist - U.S. Operators" or "RVSM Approval Checklist - Non−U.S. Operators" (as applicable). These are job aids or checklists that show aircraft/operator approval process events with references to related RVSM documents published on the website
      3. Under "Documents Applicable to All RVSM Approvals," review "RVSM Area New to the Operator." This document provides a guide for operators that are conducting RVSM operations in one or more areas of operation, but are planning to conduct RVSM operations in an area where they have not previously conducted RVSM operations, such as the U.S.
  • TCAS Equipage:

    • TCAS equipage requirements are contained in FAR 121.356, 125.224, 129.18 and 135.189
    • Part 91 Appendix G does not contain TCAS equipage requirements specific to RVSM, however, Appendix G does require that aircraft equipped with TCAS II and flown in RVSM airspace be modified to incorporate TCAS II Version 7.0 or a later version
  • Aircraft Monitoring:

    • Operators are required to participate in the RVSM aircraft monitoring program
    • The "Monitoring Requirements and Procedures" section of the RVSM Documentation Webpage contains policies and procedures for participation in the monitoring program
    • Ground-based and GPS−based monitoring systems are available for the Domestic RVSM program
    • Monitoring is a quality control program that enables the FAA and other civil aviation authorities to assess the in−service altitude−keeping performance of aircraft and operators
  • Registration on RVSM Approvals Databases:

    • The "Registration on RVSM Approvals Database" section of the RVSM Documentation Webpage provides policies/procedures for operator and aircraft registration on RVSM approvals databases
      1. Purpose of RVSM Approvals Databases:

        • ATC does not use RVSM approvals databases to determine whether or not a clearance can be issued into RVSM airspace
        • RVSM program managers do regularly review the operators and aircraft that operate in RVSM airspace to identify and investigate those aircraft and operators flying in RVSM airspace, but not listed on the RVSM approvals databases
      2. Registration of U.S. Operators:

        • When U.S. operators and aircraft are granted RVSM authority, the FAA Flight Standards office makes an input to the FAA Program Tracking and Reporting Subsystem (PTRS)
        • The Separation Standards Group at the FAA Technical Center obtains PTRS operator and aircraft information to update the FAA maintained U.S. Operator/Aircraft RVSM Approvals Database
        • Basic database operator and aircraft information can be viewed on the RVSM Documentation Webpage by clicking on the appropriate database icon
      3. Registration of Non−U.S. Operators

        • Non−U.S. operators can find policy/procedures for registration on the North American Approvals Registry and Monitoring Organization (NAARMO) database in the "Registration on RVSM Approvals Database" section of RVSM Documentation

Flight Planning into RVSM Airspace:

  • Operators that do not file the correct aircraft equipment suffix on the FAA or ICAO Flight Plan may be denied clearance into RVSM airspace
  • The operator will annotate the equipment block of the FAA or ICAO Flight Plan with an aircraft equipment suffix indicating RVSM capability only after the responsible civil aviation authority has determined that both the operator and its aircraft are RVSM−compliant and has issued RVSM authorization to the operator
  • General Policies for FAA Flight Plan Equipment Suffix. TBL 5−1−2, Aircraft Suffixes, allows operators to indicate that the aircraft has both RVSM and Advanced Area Navigation (RNAV) capabilities or has only RVSM capability
    1. The operator will annotate the equipment block of the FAA Flight Plan with the appropriate aircraft equipment suffix from TBL 5−1−2
    2. Operators can only file one equipment suffix in block 3 of the FAA Flight Plan
      • Only this equipment suffix is displayed directly to the controller
    3. Aircraft with RNAV Capability-For flight in RVSM airspace, aircraft with RNAV capability, but not Advanced RNAV capability, will file "/W"
      • Filing "/W" will not preclude such aircraft from filing and flying direct routes in en route airspace
  • Policy for ICAO Flight Plan Equipment Suffixes:

    1. Operators/aircraft that are RVSM−compliant and that file ICAO flight plans will file "/W" in block 10 (Equipment) to indicate RVSM authorization and will also file the appropriate ICAO Flight Plan suffixes to indicate navigation and communication capabilities
      • The equipment suffixes in TBL 5−1−2 are for use only in an FAA Flight Plan (FAA Form 7233−1)
    2. Operators/aircraft that file ICAO flight plans that include flight in Domestic U.S. RVSM airspace must file "/W" in block 10 to indicate RVSM authorization
  • Importance of Flight Plan Equipment Suffixes:

    • The operator must file the appropriate equipment suffix in the equipment block of the FAA Flight Plan (FAA Form 7233−1) or the ICAO Flight Plan. The equipment suffix informs ATC:
      1. Whether or not the operator and aircraft are authorized to fly in RVSM airspace
      2. The navigation and/or transponder capability of the aircraft (e.g., advanced RNAV, transponder with Mode C)
  • Significant ATC uses of the flight plan equipment suffix information are:

    1. To issue or deny clearance into RVSM airspace
    2. To apply a 2,000' vertical separation minimum in RVSM airspace to aircraft that are not authorized for RVSM, but are in one of the limited categories that the FAA has agreed to accommodate. (See Paragraphs 4−6−10, Procedures for Accommodation of Non−RVSM Aircraft, and 4−6−11, Non−RVSM Aircraft Requesting Climb to and Descent from Flight Levels Above RVSM Airspace Without Intermediate Level Off, for policy on limited operation of unapproved aircraft in RVSM airspace)
    3. To determine if the aircraft has "Advanced RNAV" capabilities and can be cleared to fly procedures for which that capability is required

Pilot RVSM Operating Practices and Procedures:

  • RVSM Mandate:

    • If either the operator or the aircraft or both have not received RVSM authorization (non−RVSM aircraft), the pilot will neither request nor accept a clearance into RVSM airspace unless:
      1. The flight is conducted by a non−RVSM DOD, MEDEVAC, certification/development or foreign State (government) aircraft in accordance with Paragraph 4−6−10, Procedures for Accommodation of Non−RVSM Aircraft
      2. The pilot intends to climb to or descend from FL 430 or above in accordance with Paragraph 4−6−11, Non−RVSM Aircraft Requesting Climb to and Descent from Flight Levels Above RVSM Airspace Without Intermediate Level Off
      3. An emergency situation exists
  • Basic RVSM Operating Practices and Procedures:

    • Appendix 4 of AC 91−85, Authorization of Aircraft and Operators for Flight in Reduced Vertical Separation Minimum Airspace contains pilot practices and procedures for RVSM
      • Operators must incorporate Appendix 4 practices and procedures, as supplemented by the applicable paragraphs of this section, into operator training or pilot knowledge programs and operator documents containing RVSM operational policies
    • Appendix 4 contains practices and procedures for flight planning, preflight procedures at the aircraft, procedures prior to RVSM airspace entry, in-flight (en route) procedures, contingency procedures and post flight
    • The following paragraphs either clarify or supplement Appendix 4 practices and procedures

Regulation:

  • No person may operate a civil aircraft in airspace designed as RVSM airspace unless:
    • The operator complies with the minimums set forth (appendix G)
    • The operator is authorized by the administrator or the country of register to conduct such operations
  • The administrator may authorize a deviation from the requirements of this section
  • Authorization (via clearance) is required prior to entering the RVSM environment
    • In addition, you are required to comply with the standards of Part 91 Appendix G (Operations in RVSM Airspace)
  • Though not mentioned in FARs, appendix G requires TCAS II Version 7.0 or later
  • Aircraft that fail to file the correct equipment suffix on their flight plan may be denied entry
    • Aircraft with RNAV capability with RNAV but not Advanced RNAV will file /W and will not preclude such aircraft from filing and flying direct routes in RVSM
    • The equipment suffix informs ATC:
      • Whether or not the operator and aircraft are authorized to fly in RVSM airspace
      • The navigation and/or transponder capability of the aircraft
      • Clearance issuing into RVSM
      • To apply a 2,000' vertical separation minimum for those aircraft not RVSM equipped
      • To determine if the aircraft has A-RNAV and can be cleared to fly procedures for which that capability is required
  • Between FL 180 and FL 290, the minimum altitude separation is 1,000' between aircraft
  • However, for flight above FL 290 (primarily due to aircraft equipage and reporting capability; potential error) ATC applied the requirement of 2,000' of separation
  • FL 290, an altitude appropriate for an eastbound aircraft, would be followed by FL 310 for a westbound aircraft, and so on to FL 410, or seven FLs available for flight
  • With 1,000' separation, or a reduction of the vertical separation between FL 290 and FL 410, an additional six FLs become available
  • This results in normal flight level and direction management being maintained from FL 180 through FL 410
  • Because it is applied domestically, it is called United States Domestic Reduced Vertical Separation Minimum, or DRVSM
  • However, there is a cost to participate in the DRVSM program, which relates to both aircraft equipage and pilot training
    • For example, altimetry error must be reduced significantly and operators using RVSM must receive authorization from the appropriate civil aviation authority
  • The aircraft must be equipped with at least one automatic altitude control:
    • Within a tolerance band of ± 65' about an acquired altitude when the aircraft is operated in straight-and-level flight
    • Within a tolerance band of ± 130' under no turbulent 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
  • That 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 (in most cases) 200'
  • 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'
  • Most noteworthy, however, is the economization that aircraft can take advantage of by the higher FLs being available to more aircraft

Operating Practices and Procedures:

  • If either the operator or the aircraft, or both, have not received RVSM authorization (non-RVSM aircraft), the pilot will neither request nor accept a clearance into RVSM airspace unless:
    • The flight is conducted by a non-RVSM DOD, Lifeguard, certification/development, or foreign State (government) aircraft in accordance with AIM paragraph 4-6-10
    • The pilot intends to climb to or descend from FL430 or above in accordance with AIM paragraph 4-6-11
    • An emergency situation exists
  • Operators must incorporate Appendix 4 practices and procedures of Guidance 91-RVSM
    • Found on the RVSM Documentation Web page under "Documents Applicable to All RVSM Approvals"

Pilot/Controller Phraseology:

RVSM Phraseology
Figure 1: RVSM Phraseology

Contingency Actions: Weather Encounters and Aircraft System Failures (after entry)

  • Initial Pilot Actions in Contingency Situations:

    • Initial pilot actions when unable to maintain flight level (FL) or unsure of aircraft altitude-keeping capability:
      • Notify ATC and request assistance as detailed below
      • Maintain cleared flight level, to the extent possible, while evaluating the situation
      • Watch for conflicting traffic both visually and by reference to TCAS, if equipped
      • Alert nearby aircraft by illuminating exterior lights (commensurate with aircraft limitations)
  • Severe Turbulence and/or Mountain Wave Activity (MWA) Induced Altitude Deviations of Approximately 200'

    • Pilot Will:

      • When experiencing severe turbulence and/or MWA induced altitude deviations of approximately 200' or greater, pilot will contact ATC and state "Unable RVSM Due (state reason)" (e.g., turbulence, mountain wave)
      • If not issued by the controller, request vector clear of traffic at adjacent FLs
      • If desired, request FL change or re-route
      • Report location and magnitude of turbulence or MWA to ATC
    • Controller Will:

      • Vector aircraft to avoid merging target with traffic at adjacent flight levels, traffic permitting
      • Advise pilot of conflicting traffic
      • Issue FL change or re-route, traffic permitting (AIM 4-6-6) explains "traffic permitting")
      • Issue PIREP to other aircraft
  • Mountain Wave Activity (MWA) Encounters - General:

    • Pilot actions:

      • Contact ATC and report experiencing MWA
      • If so desired, pilot may request a FL change or re-route
      • Report location and magnitude of MWA to ATC
    • Controller actions:

      • Advise pilot of conflicting traffic at adjacent FL
      • If pilot requests, vector aircraft to avoid merging target with traffic at adjacent RVSM flight levels, traffic permitting
      • Issue FL change or re-route, traffic permitting
      • Issue PIREP to other aircraft
      • Note that MWA encounters do not necessarily result in altitude deviations on the order of 200'. The guidance below is intended to address less significant MWA encounters
  • Wake Turbulence Encounters

    • Pilot actions:

      • Contact ATC and request vector, FL change or, if capable, a lateral offset
    • Controller actions:

      • Issue vector, FL change or lateral offset clearance, traffic permitting
  • "Unable RVSM Due Equipment"
    Failure of Automatic Altitude Control System, Altitude Alerter or All Primary Altimeters

    • Pilot actions:

      • Contact ATC and state "Unable RVSM Due Equipment"
      • Request clearance out of RVSM airspace unless operational situation dictates otherwise

    • Controller actions:

      • Provide 2,000' vertical separation or appropriate horizontal separation
      • Clear aircraft out of RVSM airspace unless operational situation dictates otherwise
  • One Primary Altimeter Remains Operational

    • Pilot Will:

      • Cross check stand-by altimeter
      • Notify ATC of operation with single primary altimeter
      • If unable to confirm primary altimeter accuracy, follow actions for failure of all primary altimeters
    • Controller Will:

      • Acknowledge operation with single primary altimeter
  • Transponder Failure

    • Pilot Will:

      • Contact ATC and request authority to continue to operate at cleared flight level
      • Comply with revised ATC clearance, if issued
      • Note that 14 CFR Section 91.215 (ATC transponder and altitude reporting equipment and use) regulates operation with the transponder inoperative
    • Controller Will:

      • Consider request to continue to operate at cleared flight level
      • Issue revised clearance, if necessary

Procedures for Accommodation of Non-RVSM Aircraft:

  • 14 CFR Section 91.180 and Part 91 Appendix G enable the FAA to authorize a deviation to operate a non-RVSM aircraft in RVSM airspace
  • General Policies for Accommodation of Non−RVSM Aircraft:

    • The RVSM mandate calls for only RVSM authorized aircraft/operators to fly in designated RVSM airspace with limited exceptions
    • If either the operator or aircraft or both have not been authorized to conduct RVSM operations, the aircraft will be referred to as a "non-RVSM" aircraft
      • YOU: "[Facility], [Callsign], [Flight Level], negative RVSM"
    • Non-RVSM aircraft flights will be handled on a workload permitting basis
      • The vertical separation standard applied between aircraft not approved for RVSM and all other aircraft shall be 2,000'
  • Categories of Non−RVSM Aircraft that may be Accommodated:

    • Subject to FAA approval and clearance, the following categories of non-RVSM aircraft may operate in domestic U.S. RVSM airspace, provided they have an operational transponder:
      • Department of Defense (DOD) aircraft
      • Flights conducted for aircraft certification and development purposes
      • Active air ambulance flights utilizing a "MEDEVAC" call sign
      • Aircraft climbing/descending through RVSM flight levels (without intermediate level off) to/from FLs above RVSM airspace (Policies for these flights are detailed below
      • Foreign State (government) aircraft
  • Methods for operators of non−RVSM aircraft to request access to RVSM Airspace:
    • LOA/MOU:

      • Enter into a Letter of Agreement (LOA)/Memorandum of Understanding (MOU) with the RVSM facility (the Air Traffic facility that provides air traffic services in RVSM airspace). Operators must comply with LOA/MOU
    • File−and−Fly:

      • File a flight plan to notify the FAA of their intention to request access to RVSM airspace
    • NOTE-Priority for access to RVSM airspace will be afforded to RVSM compliant aircraft, then File−and−Fly flights

Center Phone Numbers:


Non-RVSM Aircraft Requesting Climb to and Descent from Flight Levels Above RVSM Airspace Without Intermediate Level Off:

  • File-and-Fly:

    • Operators of Non-RVSM aircraft climbing to and descending from RVSM flight levels should just file a flight plan
  • Non-RVSM aircraft climbing to and descending from flight levels above RVSM airspace will be handled on a workload permitting basis
    • The vertical separation standard applied in RVSM airspace between non-RVSM aircraft and all other aircraft shall be 2,000'
  • Non-RVSM aircraft climbing to/descending from RVSM airspace can only be considered for accommodation provided:

    • Aircraft is capable of a continuous climb/descent and does not need to level off at an intermediate altitude for any operational considerations and
    • Aircraft is capable of climb/descent at the normal rate for the aircraft
  • Required Pilot Calls: The pilot of non-RVSM aircraft will inform the controller of the lack of RVSM approval in accordance with the direction provided above:
    • YOU: "[Facility], [Callsign], [Flight Level], negative RVSM"

References: