Re: parallel runways on airports

Date:         25 Mar 97 03:38:09 
From: (Paulo Santos)
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In article <airliners.1997.791@ohare.Chicago.COM>,
Kenneth W. Saunders <> wrote:
>The FAA has an on-going project to use high resolution displays and more
>accurate surveillance systems (radar or other means) to reduce the 4300 ft
>spacing.  Some studies have shown that 3400 ft spacing is safe with the
>Parallel Runway Monitor system.  To my knowledge, there's no operational PRM
>controlling traffic in the US.

The first set has been proposed, for MSP (Minneapolis-St. Paul).  I have a
copy of the TERPS forms for those approaches.  The PRM remarks are quite
interesting, so I am going to transcribe them here.


Before initiating a simultaneous close parallel ILS PRM approach, PILOTS

1. ATIS: When the ATIS broadcast advises ILS PRM approaches are in progress,
pilots will NOTIFY ATC on initial contact if they cannot meet the requirements
on this information page.

2. Dual VHF Communication required: To avoid blocked transmissions, pilots will
be assigned the tower frequency as primary and a secondary frequency (listen
only) for the PRM controller.

3. TCAS: Prior to beginning the approach in TCAS equipped aircraft, pilots
should select TA only (not TA/RA) to avoid possible RA commands.

4. All ATC directed "breakouts" are to be HAND FLOWN: Pilots, when directed
to breakoff an approach, must assume that an aircraft is blundering toward
their course and a breakout must be initiated immediately.  The breakout must
be hand flown to assure it is accomplished in the shortest amount of time.
Controllers may give a descending breakout but in no case will the descent be
below minimum vectoring altitude (MVA).

5. Phraseology - "TRAFFIC ALERT": If an aircraft enters the "NO TRANSGRESSION
ZONE" (NTZ), the controller will breakout the threatened aircraft on the
adjacent approach.  The phraseology for the breakout will be: "TRAFFIC ALERT,
(aircraft call sign) TURN (left/right) IMMEDIATELY, HEADING (degrees),

>I don't know how much the FAA relaxes these rules in VMC, although I've flown
>into airports (e.g. Denver Stapleton) with closely spaced parallel runways
>in VMC where the two aircraft on approach were not staggered.  I'm not sure
>if the FAA allows approaches to runways spaced closer than 2000 ft apart in
>VMC, but there may be special case airports where this is allowed.

In VMC, the controller, after confirming that the aircraft involved have
each other in sight, can issue instructions for the pilots to "maintain
visual separation with that traffic, cleared for the visual approach
runway 35 right".  If the pilots accept the clearance, it becomes
their responsibility to maintain the separation.  Minimum separation
will then be whatever the pilots and the operations rules of their airlines

Paulo Santos