Boundaries between Approach/Departure and Center

-----Original Message-----
From: Sam Spade ]
Posted At: Sunday, January 21, 2007 1:44 PM
Posted To: rec.aviation.ifr
Conversation: Boundaries between Approach/Departure and Center
Subject: Boundaries between Approach/Departure and Center

Good answer. Next question: why isn't all airspace in the United
States
controlled airspace?


Let me guess: we haven't paid enough taxes yet and don't own it all?

Sam Spade writes:

Good answer. Next question: why isn't all airspace in the United States
controlled airspace?

Why should it be?

The main reason for controlled airspace is to keep aircraft from
hitting each other when they cannot see each other. A lesser reason
is to optimize traffic flow in areas of heavy traffic. If traffic is
not heavy and aircraft can maintain visual separation, they don't need
controlled airspace.

--
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I don't know, but I'm afarid we'll get there one day
as the reaches of the federal government continues
to grow. There is a control tower being built right
now at my local airport.

What's the reason?

Ronnie

"Sam Spade" wrote in message
...
Good answer. Next question: why isn't all airspace in the United States
controlled airspace?

Ronnie wrote:

The Air Traffic Control System Command Center owns all controlled
airsapce in the US. They allocate authority to 21 ATC Centers via
letters
of authorization (LOA) that specify the lateral and vertical boundaries
of each
center's airspace. The centers divide their airspace up into high
alititude
and low altitude areas with each sub-divided into multiple sectors. The
laterial
and vertical boundaries of each sector are designed to handle the
particular
geographical area and traffic flows.

Centers delegate authority to the approach / departure radar facilities
(TRACONs)
within their airspace via letters of authorization that define the
lateral and vertical
boundaries of the TRACON's airspace. There are 197 TRACONs in the US as
of
the last time I checked.

TRACONs in turn grant airspace autority via LOA to the tower facilities
within
their airspace. Again, laterial and vertical boundaries are defined in
the LOA.

Handoffs occur when a flight crosses a boundary between facilities or
sectors.
None of the charts show all these boundaries. Sectionals show controlled
airspace
associated with an airport terminal area, but there usually multiple
sectors within a
large TRACON. Low altitude IFR En Route charts show the center
boundaries,
but not the sector boundaries. Frequencies as charted for the various
sectors in a
general area, but these are not always the frequencies that a flight will
be given during
a handoff. Instrument flights deal with this by simply following the
instructions
given by ATC; eg. "N54321 contact Memphis Center on 134.25." We don't
concern our selves about where the boundaries are, because we will be
prompted
during the hand-off. Also, you may be given a hand-off before or after
you cross
an ATC boundary, depending on controller work load, his ability to
coordinate with
the receiving controller, and aircraft speed.

Should you miss a hand-off or get out of range before a hand-off occurs,
simply find
a center frequency or TRACON frequency within range and call to
re-establish
communication. If you are not on the correct frequency, the controller
will get you
to the correct one.



"Mxsmanic" wrote in message
...

What determines the boundaries between airspace managed by an en-route
ATC center and an approach or departure center? I don't see any clear
indication of which is which on sectionals. There are boxes saying
who to contact for approach, but nothing that shows where the handoffs
between terminal control and center usually occur. Is there a general
rule?

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Ronnie writes:

I don't know, but I'm afarid we'll get there one day
as the reaches of the federal government continues
to grow. There is a control tower being built right
now at my local airport.

What's the reason?

It's being built to help you, of course.

--
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Ronnie wrote:
I don't know, but I'm afarid we'll get there one day
as the reaches of the federal government continues
to grow. There is a control tower being built right
now at my local airport.

What airport?




What's the reason?

It may have nothing to do with the federal government. Most new towers
these days are built because the owners of the airport(city, county,
etc) want one.

JOBS

Newps wrote:
Ronnie wrote:
I don't know, but I'm afarid we'll get there one day
as the reaches of the federal government continues
to grow. There is a control tower being built right
now at my local airport.

What airport?




What's the reason?

It may have nothing to do with the federal government. Most new towers
these days are built because the owners of the airport(city, county,
etc) want one.

Ronnie wrote:

I don't know, but I'm afarid we'll get there one day
as the reaches of the federal government continues
to grow. There is a control tower being built right
now at my local airport.

What's the reason?

Ronnie

Beats me.

That's Class D airspace.

I should have been more specific: why isn't all airspace that isn't
Class A, B, C, or D made into Class E airspace? That would make random
IFR operations easier and would impose no communications or control
requirement on VFR aircraft, although VFR weather minimums below 10,000
are affected.

Sam Spade writes:

I should have been more specific: why isn't all airspace that isn't
Class A, B, C, or D made into Class E airspace?

That is practically the case already in much of the U.S.

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Thought most all IFR handoffs were automated?
Al


"Ronnie" wrote in message
et...
The Air Traffic Control System Command Center owns all controlled
airsapce in the US. They allocate authority to 21 ATC Centers via letters
of authorization (LOA) that specify the lateral and vertical boundaries of
each
center's airspace. The centers divide their airspace up into high
alititude
and low altitude areas with each sub-divided into multiple sectors. The
laterial
and vertical boundaries of each sector are designed to handle the
particular
geographical area and traffic flows.

Centers delegate authority to the approach / departure radar facilities
(TRACONs)
within their airspace via letters of authorization that define the lateral
and vertical
boundaries of the TRACON's airspace. There are 197 TRACONs in the US as
of
the last time I checked.

TRACONs in turn grant airspace autority via LOA to the tower facilities
within
their airspace. Again, laterial and vertical boundaries are defined in
the LOA.

Handoffs occur when a flight crosses a boundary between facilities or
sectors.
None of the charts show all these boundaries. Sectionals show controlled
airspace
associated with an airport terminal area, but there usually multiple
sectors within a
large TRACON. Low altitude IFR En Route charts show the center
boundaries,
but not the sector boundaries. Frequencies as charted for the various
sectors in a
general area, but these are not always the frequencies that a flight will
be given during
a handoff. Instrument flights deal with this by simply following the
instructions
given by ATC; eg. "N54321 contact Memphis Center on 134.25." We don't
concern our selves about where the boundaries are, because we will be
prompted
during the hand-off. Also, you may be given a hand-off before or after
you cross
an ATC boundary, depending on controller work load, his ability to
coordinate with
the receiving controller, and aircraft speed.

Should you miss a hand-off or get out of range before a hand-off occurs,
simply find
a center frequency or TRACON frequency within range and call to
re-establish
communication. If you are not on the correct frequency, the controller
will get you
to the correct one.



"Mxsmanic" wrote in message
...
What determines the boundaries between airspace managed by an en-route
ATC center and an approach or departure center? I don't see any clear
indication of which is which on sectionals. There are boxes saying
who to contact for approach, but nothing that shows where the handoffs
between terminal control and center usually occur. Is there a general
rule?

--
Transpose mxsmanic and gmail to reach me by e-mail.

Ronnie writes:

The Air Traffic Control System Command Center owns all controlled
airsapce in the US. [...]

Thanks for the excellent explanation!

Are the boundaries fixed at all times, or can they vary by time of
day, day of week, etc.?

Are the LOAs confidential, or simply not generally published?

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