Section 5. Radar Separation

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    Section 5. Radar Separation

    5-5-1. APPLICATION

    1. Radar separation must be applied to all RNAV aircraft operating at and below FL450 on Q routes or random RNAV routes, excluding oceanic airspace.

      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.

    2. Radar separation may be applied between:
      1. Radar identified aircraft.
      2. An aircraft taking off and another radar identified aircraft when the aircraft taking off will be radar-identified within 1 mile of the runway end.
      3. A radar-identified aircraft and one not radar-identified when either is cleared to climb/descend through the altitude of the other provided:
        1. (a) The performance of the radar system is adequate and, as a minimum, primary radar targets or ASR-9/Full Digital Radar Primary Symbol targets are being displayed on the display being used within the airspace within which radar separation is being applied; and
        2. (b) Flight data on the aircraft not radar- identified indicate it is a type which can be expected to give adequate primary/ASR-9/Full Digital Radar Primary Symbol return in the area where separation is applied; and
        3. (c) The airspace within which radar separation is applied is not less than the following number of miles from the edge of the radar display:
          1. (1) When less than 40 miles from the antenna- 6 miles;
          2. (2) When 40 miles or more from the antenna- 10 miles;
          3. (3) Narrowband radar operations- 10 miles; and
        4. (d) Radar separation is maintained between the radar-identified aircraft and all observed primary, ASR-9/Full Digital Radar Primary Symbol, and secondary radar targets until nonradar separation is established from the aircraft not radar identified; and
        5. (e) When the aircraft involved are on the same relative heading, the radar-identified aircraft is vectored a sufficient distance from the route of the aircraft not radar identified to assure the targets are not superimposed prior to issuing the clearance to climb/descend.
      4. A radar-identified aircraft and one not radar-identified that is in transit from oceanic airspace or non-radar offshore airspace into an area of known radar coverage where radar separation is applied as specified in Paragraph 8-5-5, Radar Identification Application, until the transiting aircraft is radar-identified or the controller establishes other approved separation in the event of a delay or inability to establish radar identification of the transiting aircraft.

    5-5-2. TARGET SEPARATION

    Apply radar separation:

    1. Between the centers of primary radar targets; however, do not allow a primary target to touch another primary target or a beacon control slash.
    2. Between the ends of beacon control slashes.
    3. Between the end of a beacon control slash and the center of a primary target.
    4. All-digital displays. Between the centers of digital targets; do not allow digital targets to touch.

    5-5-3. TARGET RESOLUTION

    1. A process to ensure that correlated radar targets or digitized targets do not touch.
    2. Mandatory traffic advisories and safety alerts must be issued when this procedure is used.

      NOTE: This procedure must not be provided utilizing mosaic radar systems.

    3. Target resolution must be applied as follows:
      1. Between the edges of two primary targets or the edges of primary digitized targets.
      2. Between the end of the beacon control slash and the edge of a primary target or primary digitized target.
      3. Between the ends of two beacon control slashes.

    5-5-4. MINIMA

    Separate aircraft by the following minima:

    1. TERMINAL. Single Sensor ASR or Digital Terminal Automation System (DTAS):
      • NOTE:
      • 1. Includes single sensor long range radar mode.
      • 2. ADS-B and WAM are not selectable sources when in Single Sensor Mode.
        1. When less than 40 miles from the antenna- 3 miles.
        2. When 40 miles or more from the antenna- 5 miles.
        3. For single sensor ASR-9 with Mode S, when less than 60 miles from the antenna- 3 miles.
        4. For single sensor ASR-11 MSSR Beacon, when less than 60 miles from the antenna- 3 miles.
      1. When less than 40 miles from the antenna- 3 miles.
      2. When 40 miles or more from the antenna- 5 miles.
      3. For single sensor ASR-9 with Mode S, when less than 60 miles from the antenna- 3 miles.
      4. For single sensor ASR-11 MSSR Beacon, when less than 60 miles from the antenna- 3 miles.

        5. NOTE: Wake turbulence procedures specify increased separation minima required for certain classes of aircraft because of the possible effects of wake turbulence.

      5. If TRK appears in the data block, handle in accordance with paragraph 5-3-7, Identification Status, subparagraph b, and take appropriate steps to establish nonradar separation.

        NOTE: TRK appears in the data block whenever the aircraft is being tracked by a radar site other than the radar currently selected. Current equipment limitations preclude a target from being displayed in the single sensor mode; however, a position symbol and data block, including altitude information, will still be displayed. Therefore, low altitude alerts must be provided in accordance with paragraph 2-1-6, Safety Alert.

    2. TERMINAL. FUSION:
      1. Fusion target symbol- 3 miles.
      2. When displaying ISR in the data block- 5 miles.

        NOTE: In the event of an unexpected ISR on one or more aircraft, the ATCS working that aircraft must transition from 3-mile to 5-mile separation, or establish some other form of approved separation as soon as feasible. This action must be timely, but taken in a reasonable fashion, using the controller's best judgment, as not to reduce safety or the integrity of the traffic situation. For example, if ISR appears when an aircraft is established on final with another aircraft on short final, it would be beneficial from a safety perspective to allow the trailing aircraft to continue the approach and land rather than terminate a stabilized approach.

      3. If TRK appears in the data block, handle in accordance with Paragraph 5-3-7, Identification Status, subparagraph b, and take appropriate steps to establish non-radar separation.
      4. The ADS-B Computer Human Interface (CHI) may be implemented by facilities on a sector by sector or facility wide basis when the determination is made that utilization of the ADS-B CHI provides an operational advantage to the controller.
    3. STARS Multi-Sensor Mode - 5 miles

      NOTE: STARS Multi-Sensor Mode displays target symbols derived from radar, ADS-B, and WAM.

    4. ERAM:
      1. Below FL 600- 5 miles.
      2. At or above FL 600- 10 miles.
      3. Up to and including FL 230 where all the following conditions are met - 3 miles:
        1. (a) Within the 3 NM separation area, and:
          1. (1) Within 40 NM of the preferred radar; or
          2. (2) Within 60 NM of the preferred radar when using ASR-9 with Mode S or ASR-11 MSSR Beacon; or
          3. When operating in track-based display mode.
        2. (b) The preferred sensor and/or ADS-B is providing reliable targets.
        3. (c) Facility directives specifically define the 3 NM separation area.
        4. (d) The 3 NM separation area is displayable on the video map.
        5. (e) Involved aircraft are displayed using the 3 NM target symbol.

        NOTE: ADS-B allows the expanded use of 3 NM separation in approved areas. It is not required for and does not affect the use of radar for 3 NM separation.

      4. When transitioning from terminal to en route control, 3 miles increasing to 5 miles or greater, provided:
        1. (a) The aircraft are on diverging routes/courses, and/or
        2. (b) The leading aircraft is and will remain faster than the following aircraft; and
        3. (c) Separation constantly increasing and the first center controller will establish 5 NM or other appropriate form of separation prior to the aircraft departing the first center sector; and
        4. (d) The procedure is covered by a letter of agreement between the facilities involved and limited to specified routes and/or sectors/positions.
        • REFERENCE
        • FAA Order JO 7210.3, Para 8-2-1, Three Mile Airspace Operations.
        • FAA Order JO 7210.3, Para 11-8-15, Single Site Coverage ATTS Operations.
    5. MEARTS Mosaic Mode:
      1. Below FL 600- 5 miles.
      2. At or above FL 600- 10 miles.
      3. For areas meeting all of the following conditions - 3 miles:
        1. (a) Radar site adaptation is set to single sensor mode.
          • NOTE:
          • 1. Single Sensor Mode displays information from the radar input of a single site.
          • 2. Procedures to convert MEARTS Mosaic Mode to MEARTS Single Sensor Mode at each PVD/MDM will be established by facility directive.
        2. (b) Significant operational advantages can be obtained.
        3. (c) Within 40 NM of the sensor or within 60 NM of the sensor when using ASR-9 with Mode S or ASR-11 MSSR Beacon and within the 3 NM separation area.
        4. (d) Up to and including FL230.
        5. (e) Facility directives specifically define the area where the separation can be applied and define the requirements for displaying the area on the controller's PVD/MDM.
      4. MEARTS Mosaic Mode Utilizing Single Source Polygon (San Juan CERAP and Honolulu Control Facility only) when meeting all of the following conditions- 3 miles:
        1. (a) Up to and including FL230 within 40 miles from the antenna or within 60 NM when using ASR-9 with Mode S or ASR-11 MSSR Beacon and targets are from the adapted sensor.
        2. (b) The single source polygon must be displayed on the controller's PVD/MDM.
        3. (c) Significant operational advantages can be obtained.
        4. (d) Facility directives specifically define the single source polygon area where the separation can be applied and specify procedures to be used.
        5. (e) Controller must commence a transition to achieve either vertical separation or 5 mile lateral separation in the event that either target is not from the adapted sensor.

      WAKE TURBULENCE APPLICATION

    6. Separate aircraft operating directly behind or following an aircraft conducting an instrument approach by the minima specified and in accordance with the following:

      NOTE: Consider parallel runways less than 2,500 feet apart as a single runway because of the possible effects of wake turbulence.

      1. When operating within 2,500 feet of the flight path of the leading aircraft over the surface of the earth and less than 1,000 feet below:
        1. (a) TERMINAL. Behind super:
          1. (1) Heavy - 6 miles.
          2. (2) Large - 7 miles.
          3. (3) Small - 8 miles.
        2. (b) EN ROUTE. Behind super - 5 miles, unless the super is operating at or below FL240 and below 250 knots, then:
          1. (1) Heavy - 6 miles.
          2. (2) Large - 7 miles.
          3. (3) Small - 8 miles.
        3. (c) Behind heavy:
          1. (1) Heavy - 4 miles.
          2. (2) Large or small - 5 miles.
      2. Separate small aircraft behind a B757 by 4 miles when operating within 2,500 feet of the flight path of the leading aircraft over the surface of the earth and/or less than 500 feet below.
      3. TERMINAL. When departing parallel runways separated by less than 2,500 feet, the 2,500 feet requirement in subparagraph 2 is not required when a small departs the parallel runway behind a B757. Issue a wake turbulence cautionary advisory and instructions that will establish lateral separation in accordance with subparagraph 2. Do not issue instructions that will allow the small to pass behind the B757.
        • NOTE:
        • 1. The application of Paragraph 5-8-3, Successive or Simultaneous Departures, satisfies this requirement.
        • 2. Consider runways separated by less than 700 feet as a single runway because of the possible effects of wake turbulence.

      WAKE TURBULENCE APPLICATION

    7. In addition to subpara f, separate an aircraft landing behind another aircraft on the same runway, or one making a touch-and-go, stop-and-go, or low approach by ensuring the following minima will exist at the time the preceding aircraft is over the landing threshold:

      NOTE: Consider parallel runways less than 2,500 feet apart as a single runway because of the possible effects of wake turbulence.

      1. Small behind large- 4 miles.
      2. Small behind heavy- 6 miles.

      If the landing threshold cannot be determined, apply the above minima as constant or increasing at the closest point that can be determined prior to the landing threshold.

    8. TERMINAL. When NOWGT is displayed in an aircraft data block, provide 10 miles separation behind the preceding aircraft and 10 miles separation to the succeeding aircraft.
    9. TERMINAL. 2.5 nautical miles (NM) separation is authorized between aircraft established on the final approach course within 10 NM of the landing runway when operating in FUSION, or single sensor slant range mode if aircraft remains within 40 miles of the antenna and:
      1. The leading aircraft's weight class is the same or less than the trailing aircraft;
      2. Super and heavy aircraft are permitted to participate in the separation reduction as the trailing aircraft only;
      3. An average runway occupancy time of 50 seconds or less is documented;
      4. CTRDs are operational and used for quick glance references;
      5. Turnoff points are visible from the control tower.

    5-5-5. VERTICAL APPLICATION

    interpretation 3

    Aircraft not laterally separated, may be vertically separated by one of the following methods:

    1. Assign altitudes to aircraft, provided valid Mode C altitude information is monitored and the applicable separation minima is maintained at all times.
    2. Assign an altitude to an aircraft after the aircraft previously at that altitude has been issued a climb/descent clearance and is observed (valid Mode C), or reports leaving the altitude.
      • NOTE:
      • 1. Consider known aircraft performance characteristics, pilot furnished and/or Mode C detected information which indicate that climb/descent will not be consistent with the rates recommended in the AIM.
      • 2. It is possible that the separation minima described in para 4-5-1, Vertical Separation Minima, para 7-7-3, Separation, para 7-8-3, Separation, or para 7-9-4, Separation, might not always be maintained using subpara b. However, correct application of this procedure will ensure that aircraft are safely separated because the first aircraft must have already vacated the altitude prior to the assignment of that altitude to the second aircraft.

    5-5-6. EXCEPTIONS

    1. Do not use Mode C to effect vertical separation with an aircraft on a cruise clearance, contact approach, or as specified in paragraph 5-14-4, System Requirements, subparagraph f3.
    2. Assign an altitude to an aircraft only after the aircraft previously at that altitude is observed at or passing through another altitude separated from the first by the appropriate minima when:
      1. Severe turbulence is reported.
      2. Aircraft are conducting military aerial refueling.
      3. The aircraft previously at that altitude has been issued a climb/descent at pilot's discretion.
    3. EN ROUTE. When the position symbol associated with the data block falls more than one history behind the actual aircraft target or there is no target symbol displayed, the Mode C information in the data block must not be used for the purpose of determining separation.

    5-5-7. PASSING OR DIVERGING

    1. TERMINAL. In accordance with the following criteria, all other approved separation may be discontinued and passing or diverging separation applied when:
      1. Single Site ASR or FUSION Mode
        1. (a) Aircraft are on opposite/reciprocal courses and you have observed that they have passed each other; or aircraft are on same or crossing courses/assigned radar vectors and one aircraft has crossed the projected course of the other, and the angular difference between their courses/assigned radar vectors is at least 15 degrees.

          NOTE: Two aircraft, both assigned courses and/or radar vectors with an angular difference of at least 15 degrees, is considered a correct application of this paragraph.

        2. (b) The tracks are monitored to ensure that the primary targets, beacon control slashes, FUSION target symbols, or full digital terminal system primary and/or beacon target symbols will not touch.
      2. EN ROUTE, TERMINAL (when STARS Multi-Sensor Mode is selected). Vertical separation between aircraft may be discontinued when they are on opposite courses as defined in para 1-2-2, Course Definitions; and
        1. You are in communications with both aircraft involved; and
        2. You tell the pilot of one aircraft about the other aircraft, including position, direction, type; and
        3. One pilot reports having seen the other aircraft and that the aircraft have passed each other; and
        4. You have observed that the radar targets have passed each other; and
        5. You have advised the pilots if either aircraft is classified as a super or heavy aircraft.
        6. Although vertical separation may be discontinued, the requirements of Para 5-5-4, Minima, subparagraph g must be applied when wake turbulence separation is required.
        • EXAMPLE
        • “Traffic, twelve o'clock, Boeing Seven Twenty Seven, opposite direction. Do you have it in sight?”
        • (If the answer is in the affirmative):
        • “Report passing the traffic.”
        • (When pilot reports passing the traffic and the radar targets confirm that the traffic has passed, issue appropriate control instructions.)

    5-5-8. ADDITIONAL SEPARATION FOR FORMATION FLIGHTS

    Because of the distance allowed between formation aircraft and lead aircraft, additional separation is necessary to ensure the periphery of the formation is adequately separated from other aircraft, adjacent airspace, or obstructions. Provide supplemental separation for formation flights as follows:

    1. Separate a standard formation flight by adding 1 mile to the appropriate radar separation minima.
    2. Separate two standard formation flights from each other by adding 2 miles to the appropriate separation minima.
    3. Separate a nonstandard formation flight by applying the appropriate separation minima to the perimeter of the airspace encompassing the nonstandard formation or from the outermost aircraft of the nonstandard formation whichever applies.
    4. If necessary for separation between a nonstandard formation and other aircraft, assign an appropriate beacon code to each aircraft in the formation or to the first and last aircraft in-trail.

    NOTE: The additional separation provided in Paragraph 5-5-8, Additional Separation for Formation Flights, is not normally added to wake turbulence separation when a formation is following a heavier aircraft since none of the formation aircraft are likely to be closer to the heavier aircraft than the lead aircraft (to which the prescribed wake turbulence separation has been applied).

    5-5-9. SEPARATION FROM OBSTRUCTIONS

    interpretation 21
    1. TERMINAL. Separate aircraft from prominent obstructions depicted on the radar display by the following minima:
      1. When less than 40 miles from the antenna- 3 miles.
      2. When 40 miles or more from the antenna- 5 miles.
      3. For single sensor ASR-9 with Mode S, when less than 60 miles from the antenna - 3 miles.
      4. For single sensor ASR-11 MSSR Beacon, when less than 60 miles from the antenna - 3 miles.
      5. FUSION:
        1. (a) Fusion target symbol - 3 miles.
        2. (b) When ISR is displayed - 5 miles.

        NOTE: When operating in FUSION, distances from the antenna listed in paragraph 5-5-9, a1 through a4, do not apply.

      6. STARS Multi-Sensor Mode - 5 miles.
    2. TERMINAL. Vertical separation of aircraft above a prominent obstruction depicted on the radar display and contained within a buffer area may be discontinued after the aircraft has passed the obstruction.
    3. EAS. Apply the radar separation minima specified in Para 5-5-4, Minima.

    5-5-10. ADJACENT AIRSPACE

    1. If coordination between the controllers concerned has not been effected, separate radar-controlled aircraft from the boundary of adjacent airspace in which radar separation is also being used by the following minima:
      1. When less than 40 miles from the antenna- 1 1/2 miles.
      2. When 40 miles or more from the antenna- 2 1/2 miles.
      3. EAS:
        1. (a) Below Flight Level 600- 2 1/2 miles.
        2. (b) Flight Level 600 and above- 5 miles.
    2. Separate radar-controlled aircraft from the boundary of airspace in which nonradar separation is being used by the following minima:
      1. When less than 40 miles from the antenna- 3 miles.
      2. When 40 miles or more from the antenna- 5 miles.
      3. EAS:
        1. (a) Below Flight Level 600- 5 miles.
        2. (b) Flight Level 600 and above- 10 miles.
    3. The provisions of subparas a and b do not apply to VFR aircraft being provided Class B, Class C, or TRSA services. Ensure that the targets of these aircraft do not touch the boundary of adjacent airspace.
    4. VFR aircraft approaching Class B, Class C, Class D, or TRSA airspace which is under the control jurisdiction of another air traffic control facility should either be provided with a radar handoff or be advised that radar service is terminated, given their position in relation to the Class B, Class C, Class D, or TRSA airspace, and the ATC frequency, if known, for the airspace to be entered. These actions should be accomplished in sufficient time for the pilot to obtain the required ATC approval prior to entering the airspace involved, or to avoid the airspace.

    5-5-11. EDGE OF SCOPE

    Separate a radar-controlled aircraft climbing or descending through the altitude of an aircraft that has been tracked to the edge of the scope/display by the following minima until nonradar separation has been established:

    1. When less than 40 miles from the antenna- 3 miles from edge of scope.
    2. When 40 miles or more from the antenna- 5 miles from edge of scope.
    3. EAS:
      1. Below Flight Level 600- 5 miles.
      2. Flight Level 600 and above- 10 miles.

    5-5-12. BEACON TARGET DISPLACEMENT

    When using a radar target display with a previously specified beacon target displacement to separate a beacon target from a primary target, adjacent airspace, obstructions, or terrain, add a 1 mile correction factor to the applicable minima. The maximum allowable beacon target displacement which may be specified by the facility air traffic manager is 1/2 mile.

    • REFERENCE
    • FAA Order JO 7210.3, Para 3-6-4, Monitoring of Mode 3/A Radar Beacon Codes.
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