"leadfoot" wrote in message
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On Feb 11, 9:35 pm, John Godwin wrote:
Sam Spade wrote in news:l1Qzh.11876$c%2.1737
@newsfe12.phx:



It wasn't PAR?

In those days, it was GCA

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Please explain the difference between GCA and PAR.......


PAR is part of the GCA

http://en.wikipedia.org/wiki/Precision_Approach_Radar

http://en.wikipedia.org/wiki/Ground-Controlled_Approach

I worked as a Radio Repairman at Williams AFB in the late 70's . Our GCA
was located beside the Control tower. It had 2 PAR Positions and three
ASR positions. It does not actually control airspace it only provides
guidance for landing. If a GCA like the one at Williams was to control
airspace it would not be a GCA it would be a RAPCON (Runway APproach
CONtrol)

A brief note on ASR approaches. ASR does not determine Altitude
information. That is coming from the Aircrafts altimeter through the
aircraft transponder and the decoded by the radars IFF reciever which then
places that information on the Controllors ASR scope. Most of you already
know this but I though I'd add it for those who don't




John Hairell )
former GCA/PAR controller


As others have noted back in the Berlin Airlift days GCA was the term used
to describe what we now call PAR. At the time if the equipment and
personnel were available for ASR approaches then odds are PAR was also
available. Probably not much demand for ASR-only approaches so calling a
PAR a GCA didn't cause any problems.

It wasn't until around the mid-70s or so that there was a real push to use
the terms "PAR" or "ASR" and stop using the term "GCA" which could be
either.

Today "GCA" is the name given to any terminal radar ATC facility that
doesn't provide approach control services.

-Some GCAs are temporarily or permanently delegated a portion of the parent
approach control's airspace to run the radar pattern(s)
-Some provide only final control service and are technically RFCs (Radar
Final Control)
-The one at Randolph AFB used to only provide radar monitoring of ILSs and
was technically a RMF (Radar Monitor Facility)

All three answer to the name of "GCA"

Only USAF approach controls are called RAPCONs. The Navy calls them RATCFs,
the Army uses the term ARAC; and the FAA TRACON. No good reason for any of
it; people just like to be different :-/