Simultaneous close parallel (independent) ILS PRM
approaches are authorized for use at airports that have
parallel runways separated by at least 3,400 feet and no
more than 4,300 feet. [Figure 5-44 on page 5-54] They
are also approved for airports with parallel runways separated
by at least 3,000 feet with an offset LOC where
the offset angle is at least 2.5 degrees but no more
than 3 degrees. The offset LOC approaches are
referred to as Simultaneous Offset Instrument
Approaches (SOIA) and are discussed in depth later
in this chapter.
The PRM system provides the ability to accomplish
simultaneous close parallel (independent) ILS
approaches and enables reduced delays and fuel
savings during reduced visibility operations. It is also
the safest method of increasing ILS capacity through
the use of parallel approaches. The PRM system
incorporates high-update radar with one second or
better update time and a high resolution ATC radar
display that contains automated tracking software that
can track aircraft in real time. Position and velocity is
updated each second and a ten second projected position
is displayed. The system also incorporates visual
and aural alerts for the controllers.
Approval for ILS PRM approaches requires the airport
to have a precision runway monitoring system and a
final monitor controller who can only communicate
with aircraft on the final approach course. Additionally,
two tower frequencies are required to be used and the
controller broadcasts over both frequencies to reduce
the chance of instructions being missed. Pilot training
is also required for pilots using the PRM system. Part
121 and 135 operators are required to complete training
that includes the viewing of one of two videos
available from the FAA through the Flight Standards
District Office (FSDO) or current employer:
“RDU Precision Runway Monitor: A Pilot’s
“ILS PRM Approaches, Information for Pilots.”
When pilots or flight crews wish to decline a PRM
approach, ATC must be notified immediately and the
flight will be transitioned into the area at the convenience
of ATC. Flight crews should advise ATC within
200 NM of the landing airport if they are not qualified
or not equipped to fly a PRM approach.
The approach chart for the PRM approach typically
requires two pages and outlines pilot, aircraft, and procedure
requirements necessary to participate in PRM
operations. [Figure 5-45] Pilots need to be aware of the
differences associated with this type of ILS approach:
Immediately follow break out instructions as
soon as safety permits.
Listen to both tower frequencies to avoid missed
instructions from stuck mikes or blocked transmissions.
The final ATC controller can override
the radio frequency if necessary.
Broadcast only over the main tower frequency.
Disengage the autopilot for breakouts because
hand-flown breakouts are quicker.
Set the Traffic Alert and Collision Avoidance
System (TCAS) to the appropriate TA (traffic
advisory) or RA (resolution advisory) mode in
compliance with current operational guidance on
the attention all users page (AAUP), or other
authorized guidance, i.e., approved flight manual,
flight operations manual.
It is important to note that descending breakouts may
be issued. Additionally, flight crews will never be
issued breakout instructions that clear them below the
MVA, and they will not be required to descend at more
than 1,000 FPM.