Radar Approaches


  • Radar approaches are a kind of Ground Control Approach (GCA) using radar vice aircraft equipment to provide approach services to pilots
  • The radar controller vectors the aircraft to align it with the runway centerline and continues the vectors to keep the aircraft on course until the pilot can complete the approach and landing by visual reference to the surface
  • Two classes of radar approaches:

KNUC San Clemente Radar Approach Minimums
Figure 1: KNUC San Clemente Radar Approach Minimums


  • The only airborne radio equipment required for radar approaches is a functioning radio transmitter and receiver
  • Approach minimums are published in the front of the approach plates
  • PAR and ASR minimums are published on separate pages in the FAA Terminal Procedures Publication (TPP)
  • A radar approach may be given to any aircraft upon request and may be offered to pilots of aircraft in distress or to expedite traffic, however, an ASR might not be approved unless there is an ATC operational requirement, or in an unusual or emergency situation
    • Acceptance of a PAR or ASR by a pilot does not waive the prescribed weather minimums for the airport or for the particular aircraft operator concerned
    • The decision to make a radar approach when the reported weather is below the established minimums rests with the pilot
  • Radar can be used to advise pilots on other approaches so long as they are coincident with the PAR final and the PAR is in service

Surveillance Approach Radar (ASR):

  • An ASR is a non-precision approach which provides lateral course guidance (azimuth) only, no glide slope
  • The lack of vertical guidance results in higher approach minimums, as you would expect with a non-precision approach
    • If requested by the pilot, recommended altitudes will be issued at each mile, based on the descent gradient established for the procedure, down to the last mile that is at or above the MDA
  • The radar itself scans 360° of azimuth
  • Ultimately is used to provide aircraft locations over an area around an airport
  • Published minimums will be issued prior to descent
  • The pilot is furnished headings to fly to align the aircraft with the extended centerline of the landing runway
  • Since the radar information used for a surveillance approach is considerably less precise than that used for a precision approach, the accuracy of the approach will not be as great and higher minimums will apply
  • Upon commencing the approach at the Final Approach Fix (FAF), the pilot will be advised when to commence descent to the Minimum Descent Altitude (MDA) or, if appropriate, to an intermediate step-down fix Minimum Crossing Altitude and subsequently to the prescribed MDA
  • In addition, the pilot will be advised of the location of the Missed Approach Point (MAP) prescribed for the procedure and the aircraft's position each mile on final from the runway, airport or heliport or MAP, as appropriate
  • Normally, navigational guidance will be provided until the aircraft reaches the MAP
  • At the completion of the approach, controllers will terminate radar services and instruct the pilot to execute a missed approach unless at the MAP the pilot has the runway, airport or heliport in sight or, for a helicopter point-in-space approach, the prescribed visual reference with the surface is established
  • Also, if, at any time during the approach the controller considers that safe guidance for the remainder of the approach cannot be provided, the controller will terminate guidance and instruct the pilot to execute a missed approach
  • Similarly, guidance termination and missed approach will be effected upon pilot request and, for civil aircraft only, controllers may terminate guidance when the pilot reports the runway, airport/heliport or visual surface route (point-in-space approach) in sight or otherwise indicates that continued guidance is not required
  • Radar service is automatically terminated at the completion of a radar approach
  • The published MDA for straight-in approaches will be issued to the pilot before beginning descent
    • When a surveillance approach will terminate in a circle-to-land maneuver, the pilot must furnish the aircraft approach category to the controller
    • The controller will then provide the pilot with the appropriate MDA

Precision Approach Radar (PAR):

  • A PAR approach is one in which a controller provides highly accurate navigational guidance in azimuth and elevation to a pilot
  • PAR equipment may be used as a primary landing aid, or it may be used to monitor other types of approaches
  • Pilots are given headings to fly, to direct them to, and keep their aircraft aligned with the extended centerline of the landing runway
  • They are told to anticipate glidepath interception approximately 10 to 30 seconds before it occurs and when to start descent
  • The published Decision Height is published in the approach plates and therefore will only be if the pilot requests it [Figure 1]
  • If the aircraft is observed to deviate above or below the glidepath, the pilot is given the relative amount of deviation by use of terms "slightly" or "well" and is expected to adjust the aircraft's rate of descent/ascent to return to the glidepath
  • Trend information is also issued with respect to the elevation of the aircraft and may be modified by the terms "rapidly" and "slowly"; e.g., "well above glidepath, coming down rapidly"
  • Range from touchdown is given at least once each mile
  • If an aircraft is observed by the controller to proceed outside of specified safety zone limits in azimuth and/or elevation and continue to operate outside these prescribed limits, the pilot will be directed to execute a missed approach or to fly a specified course unless the pilot has the runway environment (runway, approach lights, etc.) in sight
  • Navigational guidance in azimuth and elevation is provided the pilot until the aircraft reaches the published Decision Height (DH)
  • Advisory course and glidepath information is furnished by the controller until the aircraft passes over the landing threshold, at which point the pilot is advised of any deviation from the runway centerline
  • Radar service is automatically terminated upon completion of the approach
  • Provides azimuth and glide slope (range and elevation)
  • Two antennas are used, one scanning the vertical and the other horizontal planes
  • Limited to 10 NM range
  • Limited to 20° azimuth
  • Limited to 7° elevation
  • =
  • Each scope is divided into two parts:
    • The upper half presents altitude and distance information, and;
    • The lower half presents azimuth and distance
  • Limits are due to the fact that only the final approach is covered on a PAR
  • Terms like "rapidly" or "slowly" or "well" or "slight" are used to describe position from desired course
  • Should always be paired with an ILS if available as a NORDO/sanity backup

No-Gyro Approach:

  • A no-gyro approach is available to a pilot under radar control who experiences circumstances wherein the directional gyro or other stabilized compass is inoperative or inaccurate
  • When this occurs, the pilot should so advise ATC and request a No−Gyro vector or approach
  • Pilots of aircraft not equipped with a directional gyro or other stabilized compass who desire radar handling may also request a No−Gyro vector or approach
  • The pilot should make all turns at standard rate and should execute the turn immediately upon receipt of instructions
    • For example, "TURN RIGHT," "STOP TURN"
  • When a surveillance or precision approach is made, the pilot will be advised after the aircraft has been turned onto final approach to make turns at half standard rate
Approach Plate Header
Figure 2: Approach Plate Header
  • Rate of descent on final can be determined from glide slope angle and ground speed based on the chart on the back of the approach plates
  • Beside the heading of RADAR is a list of frequencies on which you may use
  • An X indicate that the site is discrete; meaning it has the capability to be used but is not monitored continuously

Approach Plate Header
Figure 3: Approach Plate Header

Lost Communications:

  • If no transmissions are heard after 1 minute being vectored to final
    • 5 seconds on final (PAR) or,
    • 15 seconds on final (ASR)
  • Attempt contact on a secondary frequency if available
  • If unable to establish communication and unable to maintain VMC, proceed with a published IAP or previous instructions
    • This means dial up an ILS if available or a Final Approach Course (FAC) for a VOR/TACAN before you start an approach so you're not scrambling last second
    • Change transponder as appropriate
  • Maintain the last assigned altitude or the MSA/ESA as appropriate
  • ATC will often give you specific missed approach instructions, but in their absence, follow the FIH

Radar Approach Definitions
Figure 5: Radar Approach Definitions
Airport Surveillance Radar (ASR)
Figure 4: Airport Surveillance Radar (ASR)


  • RWY: runway the approach applies
  • GS: glide slope angle
  • TCH: threshold crossing height
  • RPI: runway point of intercept
  • CAT: category of aircraft
  • DH: decision height (PAR)
  • MDA: minimum descent altitude (ASR)
  • VIS: visibility required to shoot the respective approach
  • HAT: height above touchdown (straight in)
  • HATh: height above threshold height
  • HAA: height above airport (circling)
  • CEIL-VIS: ceiling - visibility

Figure 6: Explanation of RADAR Approach Terms
Explanation of RADAR approach terms

Two Phases:

  • Initial Pattern:
    • Guided by surveillance radar
    • Includes all maneuvering up to the point at which your aircraft is inbound on the FAC at approximately 8nm from touchdown
    • During transition to final, the controller will direct your headings and altitudes
    • All controller instructions to initiate turns and descents should be complied with immediately
    • Do not exceed 30° AoB
  • Final Pattern:
    • Angle of Bank (AoB) should approximate the number of degrees to be turned, not to exceed 1/2 standard rate (about 10°)
      • These gates keep you stable and predictable
      • Example: 2° of heading change should use a very shallow 2° AoB


  • Use 30° Angle of Bank (AoB) in pattern (clean)
  • Use 20° AoB turning base to final (dirty)
  • Not to exceed 10° AoB on final or dogleg


  1. Contact approach with your request
    • YOU: "[Facility], [Callsign], [Location], with information [ATIS], request"
      • Example: Meridian Approach, Bobcat 12, 15 miles to the west with information Charlie requesting the ASR, runway 19L"
    • ATC: "[Callsign], [Facility], go ahead"
    • YOU: "[Callsign], requesting [Approach]"
  2. Initiate the request for vectors and expect the following:
    • Type of approach and duty runway
    • "This will be a PAR/ASR approach to runway 5"
    • MDA (ASR Only)
    • Location of missed approach point (ASR Only)
    • Altimeter
    • Ceiling and visibility if below 1000' (or below highest circling minimum, whichever is greater) or visibility less than 3 miles
    • Special weather observations
    • Airport conditions important to the safe operation of the aircraft
    • Lost communication procedures "...if no transmissions received for 30 seconds (not more than 1 minute) in the pattern or five seconds on final, attempt contact on [Frequency] and proceed VFR, if unable, proceed with the TACAN approach"
    • Missed approach instructions
  3. Comply with vectors
    • Maintain situational awareness to what "leg" of the pattern you are on
    • On the downwind, make sure to reference MSL and AGL DH/MDA
    • Set up your system for the approach
    • Perform 15 minute checks as required
  4. Fly the pattern at 200 knots clean or as directed at assigned pattern altitude
  5. Remain clean until within 10 nm of runway and 30 radials of the FAC
    • This should happen on a base leg, configure then set approach/on-speed
    • Expect ATC to remind you to "perform landing checks" if at a Naval installation
    • As part of the landing checklist, lower the LAW to 10% below HAA or HAT as required on an ASR or a HAT for a PAR
    • At the beginning of a PAR final approach, you will be straight and level approach/on-speed and normally at approximately 1,500' AGL
  6. When controller informs you that you are "on glide path" (PAR) or "begin descent" (ASR), extend speed brakes (as appropriate) and begin your descent
    • Your rate of descent is calculated by half your ground speed x10 or by the descent chart on the back of the approach plates
      • GS: 160 then 16/2 = 800 FPM
      • GS: 150 then = 750 FPM
      • GS: 140 then = 700 FPM
      • GS: 130 then = 650 FPM
      • GS: 120 then = 600 FPM
  7. On the ASR final approach, the controller cannot furnish glide slope information
    • It will be up to you to establish and maintain the correct rate of descent
    • Recommended altitudes decrease 300' per mile on approximately a 3° glide slope
    • In order to smoothly level at MDA prior to the MAP, your altitudes should be slightly lower than those recommended
    • Depending on your ground speed, a descent rate of 500-700 FPM, maybe slightly higher than normal, will allow you to descend to the MDA prior to reaching the MAP
      • On an ASR you want to reach the MDA early but remember, ATC will not tell you when to level off
  8. Adjust power as required to establish a descent
    • ICS: "Speed brakes full, landing checklist complete"
  9. When making heading corrections, try to keep the amount of bank angle small so that you don't end up chasing the heading
  10. If you get off heading, don't try to correct to course but use smooth control inputs and return to your last assigned heading
  11. As you near the decision height, begin an inside/outside scan to visually acquire the runway environment
  12. When the runway is in sight and you are sure you can take it from here to a safe landing, call "Taking over visually"
  13. If you do not have the runway environment in sight when you reach the DH/MAP, execute a missed approach when instructed (make the mandatory missed approach call)

Final Approach Abnormalities During Radar Approaches:

  • The controller shall issue instructions to execute a missed approach or to climb and maintain a specific altitude and fly a specified course whenever the completion of a safe approach is questionable, because one or more of the following conditions exist:
    • Safe limits are exceeded or radical aircraft deviations are observed
    • Position or identification of the aircraft is in doubt
    • Radar contact is lost or a malfunctioning radar is suspected
    • Field conditions, conflicting traffic, or other unsafe conditions observed from the tower prevent approach completion

Radar Monitoring of Instrument Approaches:

  • PAR facilities operated by the FAA and the military services at some joint-use (civil and military) and military installations monitor aircraft on instrument approaches and issue radar advisories to the pilot when weather is below VFR minimums (1,000 and 3), at night, or when requested by a pilot
    • This service is provided only when the PAR Final Approach Course coincides with the final approach of the navigational aid and only during the operational hours of the PAR
    • The radar advisories serve only as a secondary aid since the pilot has selected the navigational aid as the primary aid for the approach
  • Prior to starting final approach, the pilot will be advised of the frequency on which the advisories will be transmitted
    • If, for any reason, radar advisories cannot be furnished, the pilot will be so advised
  • Advisory information, derived from radar observations, includes information on:
    • Passing the final approach fix inbound (non-precision approach) or passing the outer marker or fix used in lieu of the outer marker inbound (precision approach)
      • NOTE: At this point, the pilot may be requested to report sighting the approach lights or the runway
    • Trend advisories with respect to elevation and/or azimuth radar position and movement will be provided
      • NOTE: Whenever the aircraft nears the PAR safety limit, the pilot will be advised that the aircraft is well above or below the glidepath or well left or right of course. Glidepath information is given only to those aircraft executing a precision approach, such as ILS. Altitude information is not transmitted to aircraft executing other than precision approaches because the descent portions of these approaches generally do not coincide with the depicted PAR glidepath
    • If, after repeated advisories, the aircraft proceeds outside the PAR safety limit or if a radical deviation is observed, the pilot will be advised to execute a missed approach unless the prescribed visual reference with the surface is established
  • Radar service is automatically terminated upon completion of the approach


  • To learn more about instrument procedures, be sure to check out the Instrument Procedures Handbook online or on paperback