View Full Version : Runway capacity enhancement measures in the US

Flying Lawyer
23rd Mar 2004, 20:14
FODCOM 6/2004
Issued 23 March 2004

The FAA is introducing runway capacity enhancing measures at aerodromes in the United States. This comprises ILS Precision Runway Monitor (ILS/PRM), Localiser type Direction Aid Precision Runway Monitor (LDA/PRM) also known as Simultaneous Offset Instrument Approaches (SOIA).
The FAA requires Part 129 operators (Foreign Air Carriers & Foreign Operators of US-registered aircraft engaged in common carriage) to complete certain training prior to conducting these approaches and for the national aviation authority to confirm this to them. Following the satisfactory FAA presentation of the PRM risk analysis, the CAA accepts that UK operators may conduct ILS/PRM and LDA/PRM (SOIA) approaches in the USA, on completion of the training requirements detailed below.
ILS Precision Runway Monitor (ILS/PRM) and Localiser Type Direction Aid (with glide-slope) Precision Runway Monitor LDA/PRM (Simultaneous Offset instrument Approach – SOIA)
ILS/PRM procedures enable simultaneous independent approaches in instrument meteorological conditions (IMC) to be made to parallel or near-parallel runways whose centre lines are spaced less than 4300 feet apart and more than 3000 feet apart.
LDA/PRM (SOIA) for staggered approaches to runways spaced between 3000 feet and 750 feet. This has all the protection of ILS/PRM up to the visual segment. It consists of one straight-in ILS/PRM approach and one aircraft on an offset approach that requires a cloud ceiling, based on the aircraft’s threshold speed, that will give a nominal 30 seconds to enable the crew to see and identify the landing runway, see the other traffic ahead making an ILS to the parallel runway and inform ATC prior to reaching the MAP. The crew then positions the aircraft visually to the runway centre line, maintaining visual separation from the preceding aircraft, to be stabilised by 500 feet.
Note: The trailing (offset approach) aircraft will always be the heavy, for wake separation purposes. This meansthat UK aircraft will be most likely to conduct the offset approach.

FAA plans:
ILS/PRM procedures - Minneapolis-St Paul, Philadelphia, San Francisco International, St Louis, Cleveland and New York/JFK. Other aerodromes will probably follow.
LDA/PRM (SOIA) - San Francisco International and St Louis.

When these procedures are fully implemented, operators flying to those airports who are not ILS/PRM and LDA/PRM (SOIA) approved are expected to contact the FAA Air Traffic Control System Centre (ATCSCC), prior to departure, to receive a pre-coordinated arrival time.
Note:Operators not able to accept a PRM clearance, who have not called for a pre-coordinated arrival time, can expect delays or to be requested to divert to their alternate airports.

ILS/PRM and LDA/PRM (SOIA) Approval
This approval will be granted by the FAA upon receipt of notification from the CAA of completion of operator training, and the Part 129 approval will be amended accordingly.
To gain approval, operators should introduce a training programme in accordance with the requirements found at http://www.faa.gov/avr/afs/hbat/hbat0303A.pdf
The video can be viewed or downloaded via links on the following page: http://www.faa.gov/avr/afs/prmtraining/

Full details: FODCOM 06/04 (http://www.caa.co.uk/docs/33/FOD200406.pdf)

Tudor Owen

Aaron Kearney
23rd Mar 2004, 20:28
Forgive my ignorance, but what difference does this present when compared to existing regs?

Feather #3
23rd Mar 2004, 20:38
It means that you can do simultaneous dual parallel approaches to closer spaced runways that those at, say, LAX.

G'day ;)

Fright Level
23rd Mar 2004, 21:54
And it seems the Aussies set TA on the PRM approaches (as we already do on SFO/LAX type close parallel approaches) but the FAA has not addressed this issue and is happy for pilots to leave the transponder in RA/TA. (Link to other thread (http://www.pprune.org/forums/showthread.php?s=&threadid=121147)). Our company training is following the "no comment" from the FAA other than to say if a TCAS resolution is triggered during a PRM approach then the heading should be flown according to the PRM controller but the TCAS vertical guidance overrides.

I'm still concerned about using TA on traditional parallel approaches but then not on closer PRM runways. Despite the controllers best efforts, surely the TCAS is going to get twitchy about the other aircraft?

24th Mar 2004, 10:49
Already done the training for this in the sim. The breakout with a climb is pretty straightforward but the instruction to descend and turn from low altitude was interesting to say the least!

24th Mar 2004, 15:15
Have to run and check my Jepps, but I believe the FAA does require operators to put TCAS into RA advisory only to preclude contradictory instructions during breakout.

Of all the approaches listed...the PRM/SOIA into KSTL is definately the most interesting, though traffic conditions into STL hardly warrant it anymore, unfortunately.

25th Mar 2004, 05:28
My only experience of PRM was the initial trials at Minny. During those trials aircraft were allowed to take-off while a PRM aircraft was on approach. Since the localiser signal could be compromised by the departing aircraft, perhaps enough to cause an undetectable track deviation, (localiser bar would stay centered due to the bent beam) this did not seem like a good idea.

Have not looked at this procedure much but it would seem that, to be fully safe, it may not provide much increase in airport capacity. I would think take-offs should be restricted while an aircraft is using the ILS/PRM and that aircraft on the same ILS would need wide longitudinal separation to prevent loc/gs distortion caused by the first aircraft.