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A Pilot’s Guide to ILS PRM Approaches

Introduction

This page provides an overview of Precision Runway Monitor (PRM) operations at Sydney (Kingsford-Smith) Airport (YSSY/SYD).

Pilot training may include viewing of the following video as required by CASA, other National Aviation Authorities, or company operations manuals.

Note: The PRM video is currently under production. Download this presentation as necessary to supplement pilot training.

The last change (23 May 2019) to PRM operations was removal of separate ILS PRM approach plates. Refer to AIC H15/19 for more information

Purpose of PRM operations

During periods of the day with peak arrival demand and inclement weather, capacity at Sydney Airport can be maintained with the use of PRM operations. A highly accurate surveillance system allows ATC to precisely monitor aircraft tracking on their approach paths and permit independent parallel instrument approaches.

Flying into Sydney during PRM operations

When “PRM OPERATIONS IN PROGRESS” is notified from ATC by voice or ATIS, special procedures and notification requirements apply.

  • PRM capable
    • Training has met the legislative requirements of CASA 24/18
    • Dual VHF
      • COM1 – TWR (RX & TX)
      • COM2 – PRM (RX only) selected when transferred to TWR
    • Expect instrument approach annotated with “PRM OPS”
    • Approach brief to include “PRM User Instructions”
  • Not PRM capable
    • Notify ATC at least 120 NM from YSSY
    • Expect additional delay

Aircraft separation during PRM operations

ATC maintains separation (e.g. 1000FT or 3NM) between aircraft until they are established inbound on the instrument approach.
Once established, ATC will monitor aircraft clear of the “No Transgression Zone” (NTZ), which is a 610m-wide safety buffer between the parallel approaches.
ATC will warn pilots if they are observed deviating towards the NTZ. If an aircraft penetrates the NTZ, ATC will “break-out” that aircraft and any conflicting aircraft on the adjacent approach in order to establish separation.

Break-out procedure

A break-out is an immediate evasive manoeuvre instructed by ATC to turn an aircraft on final approach away from another aircraft. Although a break-out is used to abort an approach, it is entirely different procedure to a missed approach. Key differences:

  • Track & level. Pilots will be issued with an immediate heading and level, typically involving an initial climbing turn away from centreline. In unusual circumstances, descending break-out instructions may be given but this will not be an altitude below the minimum vectoring altitude (MVA).
  • Hand flown. A break-out instruction can be given with little or no advance warning. Time is critical. Simulation studies have consistently demonstrated that to obtain the quickest response, all break-out procedures must be hand flown.
  • Example phraseology: ‘BREAKOUT ALERT, (callsign) TURN LEFT IMMEDIATELY HEADING 110, CLIMB TO MAINTAIN 3000’

FAQs

  • Why dual VHF? Due to the close spacing between the parallel runways at Sydney, delay in giving break-out instructions must be minimised. At times this may require the PRM controller to over-transmit other aircraft or the TWR controller. The PRM frequency will always be clear for pilots to receive instructions even if the TWR frequency is blocked.
  • Why do TWR transmissions also come through the PRM frequency? This permits the volume of COM2 to be set correctly.
  • The circuit sometimes seems so much longer compared to IVAs, is this really efficient? If PRM operations aren’t used, and the weather doesn’t permit IVAs, arrival capacity at Sydney is reduced by up to 25%. PRM operations permit maximum sustained capacity in these conditions. The circuit is longer due to specific requirements when vectoring for independent parallel instrument approaches.
  • Why does the BOREE PAPA STAR have a long level segment at 3000FT? To maintain separation with traffic being vectored for 16L, arrivals via BOREE to 16R need to be pushed down to 3000 FT much earlier than normal. Compliance with all level restrictions on this STAR are critical for separation.
  • What separation is provided with aircraft outside controlled airspace under the circuit to 16R? ATC will often vector aircraft with a 500FT buffer from the base of class C airspace while positioning for the 16R approach at 3000FT. It is not uncommon for uncontrolled aircraft to transit underneath the circuit at 2500FT.

Environmental considerations

In implementing PRM in the runway 16 direction at Sydney, Airservices has provided assurance that it will, consistent with the overriding concern for air safety, take action to limit the northern extent downwind leg and to minimise the length of time that aircraft maintain 3000 FT. Controller training is designed to meet these objectives. It is essential that aircrew are aware of these objectives and assist by bearing in mind the following factors:

  • Descent profile should be maintained in accordance with the distance to run to touchdown or the ‘base turn’ point notified by ATC.
  • On a right circuit for a PRM approach to runway 16R, aircraft must generally reach 3000FT by the base turn, and at least 6NM from the initial approach fix. Likewise, a right circuit to runway 34R requires aircraft to be near 2000ft before a base turn. Controllers will provide information to pilots when expedited descent is required.