MVAs in AZ

Not sure about AZ but in California the min altitudes often change with
time of day as well depending on what facility is open.

-Robert

Dan wrote:
Does anyone with an ATC "in" know how one might get a map/description
of the minimum vectoring altitudes in Arizona?

--Dan

MVAs are associated with TRACONs and MIAs are associated with centers.

Both are based primarily on obstacles and containment within controlled
airspace. They don't change at all, except when a periodic review is
conducted.

But, a few TRACONs, such as Palm Springs, CA, close at night so the much
higher center MIAs take effect. The MIAs are higher because they have
larger buffers (less accurate center radar) and usually cover larger areas.

Having said that MVAs and MIAs don't change. Altitudes available for
assignment often change because of airspace agreements between TRACONs
or between TRACONs and centers. But, those restrictions are quite
different than MVAs.

Robert M. Gary wrote:
Not sure about AZ but in California the min altitudes often change with
time of day as well depending on what facility is open.

-Robert

Sam Spade wrote:


But, a few TRACONs, such as Palm Springs, CA, close at night so the much
higher center MIAs take effect. The MIAs are higher because they have
larger buffers (less accurate center radar) and usually cover larger areas.

MIA's are not automatically higher. Radar coverage enters into the
picture so if the center has a radar antenna closer than the TRACON then
the center will have a lower MIA. We use this to our benefit here.

The reason I am curious about the MIAs is to see if there are ways to
get IFR services at something lower than the MORAs listed in huge boxes
on the IFR charts. Out west, these are high, and in some cases seem to
be set higher than might really be needed.

I have a feeling it's probably a futile effort though...

--Dan


Newps wrote:
Sam Spade wrote:


But, a few TRACONs, such as Palm Springs, CA, close at night so the much
higher center MIAs take effect. The MIAs are higher because they have
larger buffers (less accurate center radar) and usually cover larger areas.

MIA's are not automatically higher. Radar coverage enters into the
picture so if the center has a radar antenna closer than the TRACON then
the center will have a lower MIA. We use this to our benefit here.

Newps wrote:


Sam Spade wrote:


But, a few TRACONs, such as Palm Springs, CA, close at night so the
much higher center MIAs take effect. The MIAs are higher because they
have larger buffers (less accurate center radar) and usually cover
larger areas.


MIA's are not automatically higher. Radar coverage enters into the
picture so if the center has a radar antenna closer than the TRACON then
the center will have a lower MIA. We use this to our benefit here.


I didn't mean to suggest that MIAs are always higher than MVAs. In
mountain areas they usually are, though.

Then, there are cases, like NorCal and Potomac TRACONs, where they use a
center ARSR as a backup. The TRACON has MVAs on such a dual-use ARSR
whereas the center has polygonal MIAs. They are quite different because
they pick up different terrain and the TRACON uses 3 mile buffers within
40 miles of the antenna because it is a single-source radar for the TRACON.

Dan wrote:

The reason I am curious about the MIAs is to see if there are ways to
get IFR services at something lower than the MORAs listed in huge boxes
on the IFR charts. Out west, these are high, and in some cases seem to
be set higher than might really be needed.

I have a feeling it's probably a futile effort though...

MORAs are square boxes. The purpose was to keep them simple. MIAs, on
the other hand, are polygons with as many as (as I recall) 11 sides.
They have that limit because of technical limitations of the en route
MSAWS software.

Nonetheless, an 11-sided polygon gives the center airspace folks a lot
of flexibility in the design of MIAs. But, that doesn't mean all MIAs
are used throughout their area of coverage. Communications and radar
coverage come into play as well.

Centers can use MIAs without radar, but that is limited except where
non-radar procedures have been established.

Some industry groups have lobbied to get MIAs into the public domain.
Thus far, there hasn't been a lot of interest. If they were on a
cockpit moving map you would have a great tool; same for MVAs.

"Newps" wrote in message
. ..

MIA's are not automatically higher. Radar coverage enters into the
picture so if the center has a radar antenna closer than the TRACON then
the center will have a lower MIA. We use this to our benefit here.


Radar coverage has nothing to do with MIAs. MIAs and MVAs are established
without regard to radar coverage.

Steven P. McNicoll wrote:

"Newps" wrote in message
. ..

MIA's are not automatically higher. Radar coverage enters into the
picture so if the center has a radar antenna closer than the TRACON then
the center will have a lower MIA. We use this to our benefit here.



Radar coverage has nothing to do with MIAs. MIAs and MVAs are established
without regard to radar coverage.


I suspect he means distance from antenna. I cut him some slack.

Also, his point is well taken. If the MIA that was established without
regard to radar coverage in fact, has radar coverage, that may very well
be at a lower altitude than his more distant TRACON ASR.

Steven P. McNicoll wrote:
"Newps" wrote in message
. ..

MIA's are not automatically higher. Radar coverage enters into the
picture so if the center has a radar antenna closer than the TRACON then
the center will have a lower MIA. We use this to our benefit here.



Radar coverage has nothing to do with MIAs. MIAs and MVAs are established
without regard to radar coverage.

"Sam Spade" wrote in message
news:2M9tg.658$_M.551@fed1read04...

I suspect he means distance from antenna. I cut him some slack.


Distance from antenna has nothing to do with MIAs. MIAs and MVAs are
established without regard to distance from antenna.