Section 4. Route Assignment

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  • Section 4. Route Assignment

    4-4-1. ROUTE USE

    Clear aircraft via routes consistent with the altitude stratum in which the operation is to be conducted by one or more of the following:

    NOTE: Except for certain NAVAIDs/routes used by scheduled air carriers or authorized for specific uses in the control of IFR aircraft, Air Traffic Service (ATS) routes, and NAVAIDs established for use at specified altitudes are shown on U.S. government charts or DOD FLIP charts.

    1. Designated ATS routes.
      • VIA:
      • VICTOR (color) (airway number)(the word Romeo when RNAV for existing Alaska routes),
      • or
      • J (route number) (the word Romeo when RNAV for existing Alaska routes),
      • or
      • Q (route number)
      • or
      • Tango (route number)
      • or
      • SUBSTITUTE (ATS route) FROM (fix) to (fix),
      • or
      • IR (route number).
      • CROSS/JOIN VICTOR/(color) (airway number), (number of miles) MILES (direction) OF (fix).
    2. Radials, courses, azimuths to or from NAVAIDs.
      • VIA:
      • (name of NAVAID) (specified) RADIAL/COURSE/AZIMUTH,
      • or
      • (fix) AND (fix),
      • or
      • RADIALS OF (ATS route) AND (ATS route).
    3. Random routes.
      1. When not being radar monitored, GNSS-equipped RNAV aircraft on random RNAV routes must be cleared via or reported to be established on a point-to-point route.
        1. (a) The points must be published NAVAIDs, waypoints, fixes or airports recallable from the aircraft's navigation database. The points must be displayed on controller video maps or depicted on the controller chart displayed at the control position. When applying nonradar separation the maximum distance between points must not exceed 500 miles.
        2. (b) Protect 4 miles either side of the route centerline.
        3. (c) Assigned altitudes must beat or above the highest MIA along the projected route segment being flown, including the protected airspace of that route segment.
      2. Impromptu
        • DIRECT (name of NAVAID/waypoint/fix/airport)

        NOTE: A random impromptu routing is a direct course initiated by ATC or requested by the pilot during flight. Aircraft are cleared from their present position to a NAVAID, waypoint, fix, or airport.

      3. Point-to-Point
        • After (fix) proceed direct (fix)

        NOTE: A point-to-point route segment begins and ends with a published NAVAID, waypoint, fix, or airport.

    4. DME arcs of NAVAIDS.
    5. Radials, courses, azimuths, and headings of departure or arrival routes.
    6. SIDs/STARs.
    7. Vectors.
    8. Fixes defined in terms of degree-distance from NAVAIDs for special military operations.
    9. Courses, azimuths, bearings, quadrants, or radials within a radius of a NAVAID.
      • CLEARED TO FLY (general direction from NAVAID) OF (NAVAID name and type) BETWEEN (specified) COURSES TO/BEARINGS FROM/RADIALS (NAVAID name when a NDB) WITHIN (number of miles) MILE RADIUS,
      • or
      • CLEARED TO FLY (specified) QUADRANT OF (NAVAID name and type) WITHIN (number of miles) MILE RADIUS.
      • EXAMPLE
      • 1. “Cleared to fly east of Allentown VORTAC between the zero four five and the one three five radials within four zero mile radius.”
      • 2. “Cleared to fly east of Crystal Lake radio beacon between the two two five and the three one five courses to Crystal Lake within three zero mile radius.”
      • 3. “Cleared to fly northeast quadrant of Philipsburg VORTAC within four zero mile radius.”
    10. Fixes/waypoints defined in terms of:
      1. Published name; or
      2. Degree-distance from NAVAIDs; or
      3. Latitude/longitude coordinates, state the latitude and longitude in degrees and minutes including the direction from the axis such as North or West; or
      4. Offset from published or established ATS route at a specified distance and direction for random (impromptu) RNAV Routes.
        • DIRECT (fix/waypoint)
        • DIRECT TO THE (facility) (radial) (distance) FIX.
        • DIRECT (number degrees) DEGREES, (number minutes) MINUTES (north or south), (number degrees) DEGREES, (number minutes) MINUTES (east or west).
        • OFFSET (distance) RIGHT/LEFT OF (route).
        • EXAMPLE
        • “Direct SUNOL.”
        • “Direct to the Appleton three one zero radial two five mile fix.”
        • “Direct 32 degrees, 45 minutes north, 105 degrees, 37 minutes west.”
        • “Offset eight miles right of Victor six.”


    To effect transition within or between route structures, clear an aircraft by one or more of the following methods, based on NAVAIDs or RNAV:

    1. Vector aircraft to or from radials, courses, or azimuths of the ATS route assigned.
    2. Assign a SID/STAR.
    3. Clear departing or arriving aircraft to climb or descend via radials, courses, or azimuths of the ATS route assigned.
    4. Clear departing or arriving aircraft directly to or between the NAVAIDs forming the ATS route assigned.
    5. Clear aircraft to climb or descend via the ATS route on which flight will be conducted.
    6. Clear aircraft to climb or descend on specified radials, courses, or azimuths of NAVAIDs.
    7. Clear RNAV aircraft between designated or established ATS routes via random RNAV routes to a NAVAID, waypoint, airport or fix on the new route. Provide radar monitoring to aircraft transitioning via random RNAV routes.
    8. Provide radar monitoring to RNAV equipped aircraft transitioning via random RNAV routes.

    EXCEPTION. GNSS-equipped aircraft /G, /L, /S, and /V on point-to-point routes, or transitioning between two point-to-point routes via an impromptu route.



    1. Do not accept a military flight plan whose route or route segments do not coincide with designated Air Traffic Service routes or with a direct course between NAVAIDs unless it is authorized in subparagraph b and meets the following degree-distance route definition and procedural requirements:
      1. The route or route segments must be defined in the flight plan by degree-distance fixes composed of:
        1. (a) A location identifier;
        2. (b) Azimuth in degrees magnetic; and
        3. (c) Distance in miles from the NAVAID used.
        • EXAMPLE
        • “MKE 030025.”
      2. The NAVAIDs selected to define the degree-distance fixes must be those authorized for use at the altitude being flown and at a distance within the published service volume area.
      3. The distance between the fixes used to define the route must not exceed:
        1. (a) Below FL 180- 80 miles;
        2. (b) FL 180 and above- 260 miles; and
        3. (c) For celestial navigation routes, all altitudes- 260 miles.
      4. Degree-distance fixes used to define a route must be considered compulsory reporting points except that an aircraft may be authorized by ATC to omit reports when traffic conditions permit.
      5. Military aircraft using degree-distance route definition procedures must conduct operations in accordance with the following:
        1. (a) Unless prior coordination has been effected with the appropriate air traffic control facility, flight plan the departure and the arrival phases to conform with the routine flow of traffic when operating within 75 miles of the departure and the arrival airport. Use defined routes or airways or direct courses between NAVAIDs or as otherwise required to conform to the normal flow of traffic.
        2. (b) Flight plans must be filed at least 2 hours before the estimated time of departure.
    2. The following special military operations are authorized to define routes, or portions of routes, by degree-distance fixes:
      1. Airborne radar navigation, radar bomb scoring (RBS), and airborne missile programming conducted by the USAF, USN, and RAF.
      2. Celestial navigation conducted by the USAF, USN, and RAF.
      3. Target aircraft operating in conjunction with air defense interceptors, and air defense interceptors while en route to and from assigned airspace.
      4. Missions conducted above FL 450.
      5. USN fighter and attack aircraft operating in positive control airspace.
      6. USN/USMC aircraft, TACAN equipped, operating within the Honolulu FIR/Hawaiian airways area.
      7. USAF/USN/USMC aircraft flight planned to operate on MTRs.
      8. USAF Air Mobility Command (AMC) aircraft operating on approved station-keeping equipment (SKE) routes in accordance with the conditions and limitations listed in FAA Exemption No. 4371 to 14 CFR Section 91.177(a)(2) and 14 CFR Section 91.179(b)(1).


    When any part of an airway or route is unusable because of NAVAID status, clear aircraft that are not RNAV capable via one of the following alternative routes:

    1. A route depicted on current U.S. Government charts/publications. Use the word “substitute” immediately preceding the alternative route in issuing the clearance.
    2. A route defined by specifying NAVAID radials, courses, or azimuths.
    3. A route defined as direct to or between NAVAIDs.
    4. Vectors.

    NOTE: Inform area navigation aircraft that will proceed to the NAVAID location of the NAVAID outage.


    Include routes through Class G airspace only when requested by the pilot.

    • NOTE:
    • 1. Separation criteria are not applicable in Class G airspace. Traffic advisories and safety alerts are applicable within Class G airspace to aircraft that are in direct communication with ATC.
    • 2. Flight plans filed for random RNAV routes through Class G airspace are considered a request by the pilot.
    • 3. Flight plans containing MTR segments in/through Class G airspace are considered a request by the pilot.


    1. Unless operational necessity dictates, do not issue a routing clearance that will take an aircraft off of its flight plan route if:
      1. The aircraft is part of a known traffic management initiative.
      2. The part of the route under consideration for the direct routing is within a protected segment. If a flight routing within a protected segment is amended, coordination must be accomplished as follows:
        1. (a) ATCS: with TMU.
        2. (b) Terminal facility TMU: with overlying ARTCC TMU.
        3. (c) ARTCC TMU (for amendments outside their facility): with ATCSCC.
    2. EN ROUTE. Do not issue revised routing clearances that will take an aircraft off its flight plan route past the last fix in your facility's airspace, unless requested by the pilot or operational necessity dictates.

    NOTE: Nothing in this paragraph must preclude a controller from issuing a routing clearance that conforms to a letter of agreement or standard operating procedure within their own facility or between facilities, is required to maintain separation or comply with traffic flow management initiatives.

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