Radar Monitoring Instrument Approaches

AIM ¶ 5-4-12 Radar Monitoring Instrument Approaches

AIM 5-4-12 explains PAR radar monitoring of instrument approaches, advisory triggers, glidepath info, and safety limits. Study guide for pilot students.

In Plain English

PAR (Precision Approach Radar) facilities at some joint-use and military airports can monitor your instrument approach and provide radar advisories as a backup to your primary navigation aid (ILS, VOR, etc.).

This service is provided automatically when:

  • Weather is below VFR minimums (1,000 ft ceiling and 3 SM visibility)
  • It's night
  • The pilot requests it

Key limitations:

  • Only available when the PAR final approach course coincides with the navaid's final approach course
  • Only during PAR operational hours
  • Advisories are secondary — your selected navaid is primary

Before final, you'll get the advisory frequency. If radar advisories aren't available, you'll be told. Advisories include:

  • Notification of passing the FAF inbound (nonprecision) or OM/fix in lieu inbound (precision)
  • Trend advisories on azimuth and (for precision approaches) elevation
  • Glidepath info only for precision approaches like ILS — not for nonprecision, since descent profiles don't match the PAR glidepath

If you drift outside the PAR safety limit or deviate radically after repeated advisories, the controller will instruct a missed approach unless you have the required visual reference. Radar service ends automatically when the approach is complete.

AIM Source Text
FAA AIM ¶ 5-4-12
5-4-12. 5-4-12. 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 (nonprecision 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.
Oral Exam Questions a DPE Might Ask
Q1When is PAR radar monitoring of an instrument approach automatically provided?
Per AIM 5-4-12, PAR monitoring is provided when weather is below VFR minimums (1,000 and 3), at night, or when requested by the pilot — and only when the PAR final approach course coincides with the navaid's final approach course and during PAR operational hours.
Q2Why is glidepath (altitude) information given only on precision approaches during PAR monitoring?
Per AIM 5-4-12, altitude information is not transmitted on nonprecision approaches because their descent profiles generally do not coincide with the depicted PAR glidepath. Glidepath advisories are only meaningful for precision approaches like ILS.
Q3What will the controller do if the aircraft proceeds outside the PAR safety limit after repeated advisories?
Per AIM 5-4-12, 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.
Related Paragraphs in AIM Chapter 5
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AIM 5-4-12 — Radar Monitoring of Instrument Approaches