Simultaneous Independent Parallel Approaches

AIM ¶ 5-4-15 Simultaneous Independent Parallel Approaches

AIM 5-4-15 explains simultaneous independent ILS/RNAV/GLS approaches to parallel runways, NTZ monitoring, breakout instructions, and pilot responsibilities.

In Plain English

Simultaneous independent approaches allow aircraft to fly approaches to parallel runways at the same time, with no staggered radar separation between them. They're authorized when runway centerlines are separated by at least 4,300 feet (up to 9,000 ft, or 9,200 ft above 5,000 ft elevation), using a No Transgression Zone (NTZ) monitored by final monitor controllers.

Key points to remember:

  • A chart note identifies approaches authorized for simultaneous use, and ATIS advertises when they're active (without saying "independent" or "parallel").
  • Pilots must immediately advise approach control of any inoperative receivers or if they don't want a simultaneous approach.
  • Only use procedures specifically authorized by chart note — e.g., "LNAV NA during simultaneous operations" means vertical guidance is required.
  • During turn-on, expect 3 NM radar or 1,000 ft vertical separation, intercept angles no greater than 30°, and maintain assigned altitude until glidepath intercept.
  • Final monitor controllers can override tower and issue breakout instructions if an adjacent aircraft threatens the NTZ.
  • Monitoring ends automatically at visual separation, runway/lights in sight, or within 1 NM of threshold — pilots are not advised when it terminates.

When given a choice, always fly a precision approach when possible.

AIM Source Text
FAA AIM ¶ 5-4-15
5-4-15. 5-4-15. Simultaneous Independent ILS/RNAV/GLS Approaches FIG 5-4-22 Simultaneous Independent ILS/RNAV/GLS Approaches System. An approach system permitting simultaneous approaches to parallel runways with centerlines separated by at least 4,300 feet. Separation between 4,300 and 9,000 feet (9,200' for airports above 5,000') utilizing NTZ final monitor controllers. Simultaneous independent approaches require NTZ radar monitoring to ensure separation between aircraft on the adjacent parallel approach course. Aircraft position is tracked by final monitor controllers who will issue instructions to aircraft observed deviating from the assigned final approach course. Staggered radar separation procedures are not utilized. Integral parts of a total system are radar, communications, ATC procedures, and ILS or other required airborne equipment. A chart note identifies that the approach is authorized for simultaneous use. When simultaneous operations are in use, it will be advertised on the ATIS. When advised that simultaneous approaches are in use, pilots must advise approach control immediately of malfunctioning or inoperative receivers, or if a simultaneous approach is not desired. Although non-precision minimums may be published, pilots must only use those procedures specifically authorized by chart note. For example, the chart note “LNAV NA during simultaneous operations,” requires vertical guidance. When given a choice, pilots should always fly a precision approach whenever possible. NOTE- ATC does not use the word independent or parallel when advertising these operations on the ATIS. EXAMPLE- Simultaneous ILS Runway 24 left and ILS Runway 24 right approaches in use. Radar Services. These services are provided for each simultaneous independent approach. During turn on to parallel final approach, aircraft are normally provided 3 miles radar separation or a minimum of 1,000 feet vertical separation. The assigned altitude must be maintained until intercepting the glidepath, unless cleared otherwise by ATC. Aircraft will not be vectored to intercept the final approach course at an angle greater than thirty degrees. NOTE- Some simultaneous operations permit the aircraft to track an RNAV course beginning on downwind and continuing in a turn to intercept the final approach course. In this case, separation with the aircraft on the adjacent final approach course is provided by the monitor controller with reference to an NTZ. The final monitor controller will have the capability of overriding the tower controller on the tower frequency. Pilots will be instructed to contact the tower frequency prior to the point where NTZ monitoring begins. Aircraft observed to overshoot the turn-on or to continue on a track which will penetrate the NTZ will be instructed to return to the correct final approach course immediately. The final monitor controller may cancel the approach clearance, and issue missed approach or other instructions to the deviating aircraft. PHRASEOLOGY- “(Aircraft call sign) YOU HAVE CROSSED THE FINAL APPROACH COURSE. TURN (left/right) IMMEDIATELY AND RETURN TO THE FINAL APPROACH COURSE,” or “(aircraft call sign) TURN (left/right) AND RETURN TO THE FINAL APPROACH COURSE.” If a deviating aircraft fails to respond to such instructions or is observed penetrating the NTZ, the aircraft on the adjacent final approach course (if threatened), will be issued a breakout instruction. PHRASEOLOGY- “TRAFFIC ALERT (aircraft call sign) TURN (left/right) IMMEDIATELY HEADING (degrees), (climb/descend) AND MAINTAIN (altitude).” Radar monitoring will automatically be terminated when visual separation is applied, the aircraft reports the approach lights or runway in sight, or the aircraft is 1 NM or less from the runway threshold. Final monitor controllers will not advise pilots when radar monitoring is terminated. NOTE- Simultaneous independent approaches conducted to runways spaced greater than 9,000 feet (or 9,200' at airports above 5,000') do not require an NTZ. However, from a pilot's perspective, the same alerts relative to deviating aircraft will be provided by ATC as are provided when an NTZ is being monitored. Pilots may not be aware as to whether or not an NTZ is being monitored.
Oral Exam Questions a DPE Might Ask
Q1What is the minimum runway centerline separation for simultaneous independent ILS/RNAV/GLS approaches, and when is an NTZ required?
Per AIM 5-4-15, simultaneous independent approaches require centerlines separated by at least 4,300 feet. NTZ final monitor controllers are used between 4,300 and 9,000 feet (9,200 feet at airports above 5,000 feet elevation). Beyond those distances, an NTZ is not required, though pilots may receive the same deviation alerts and may not know whether an NTZ is being monitored.
Q2What are your responsibilities as a pilot when ATIS advertises that simultaneous approaches are in use?
Per AIM 5-4-15, you must immediately advise approach control of any malfunctioning or inoperative receivers, or if you do not desire a simultaneous approach. You must use only procedures specifically authorized by the chart note — for example, if the note states "LNAV NA during simultaneous operations," you must fly an approach with vertical guidance. When given a choice, always fly a precision approach when possible.
Q3When does radar monitoring during a simultaneous independent approach terminate, and will ATC tell you?
Per AIM 5-4-15, radar monitoring automatically terminates when visual separation is applied, when the pilot reports the approach lights or runway in sight, or when the aircraft is 1 NM or less from the runway threshold. Final monitor controllers will not advise pilots when radar monitoring is terminated.
Related Paragraphs in AIM Chapter 5
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AIM 5-4-15 — Simultaneous Independent ILS/RNAV/GLS