MVAs in AZ

[Dan[_1_]]

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

--Dan

[Newps]

You would need to call all the facilities whose airspace you are
interested in.



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

[Sam Spade]

Dan wrote:
> Does anyone with an ATC "in" know how one might get a map/description
> of the minimum vectoring altitudes in Arizona?
>
> --Dan
>
Unless you have them on a moving map they won't do you much good.

I can overlay one of the TRACON's MVAs on a sectional but it requires a
bit of work. Tell me which one. There are only three, PHX, TUS, and YUM.

ABQ or LAX Centers provide radar services outside the TRACON areas.
Those are MIAs and much less accessible than MVAs.

[Sam Spade]

Dan wrote:
> I suppose I was more interested in MIAs then, however I'd take any MVA
> info you have (specifically interested in PHX)

Is this a valid email address?

[Dan[_1_]]

Yes.

dsfh at
cox.net

Sam Spade wrote:
> Dan wrote:
> > I suppose I was more interested in MIAs then, however I'd take any MVA
> > info you have (specifically interested in PHX)
>
> Is this a valid email address?

[Sam Spade]

It has been sent.

Dan wrote:
> Yes.
>
> dsfh at
> cox.net
>
> Sam Spade wrote:
>
>>Dan wrote:
>>
>>>I suppose I was more interested in MIAs then, however I'd take any MVA
>>>info you have (specifically interested in PHX)
>>
>>Is this a valid email address?
>

[Mike Adams[_2_]]

Sam Spade > wrote:

> It has been sent.
>
> Dan wrote:
>> Yes.
>>
>> dsfh at
>> cox.net
>>
>> Sam Spade wrote:
>>
>>>Dan wrote:
>>>
>>>>I suppose I was more interested in MIAs then, however I'd take any MVA
>>>>info you have (specifically interested in PHX)
>>>
>>>Is this a valid email address?
>>

Please post here also, or send a reference. The rest of us Arizonans are interested.

thanks,
Mike

[Sam Spade]

Mike Adams wrote:

> Sam Spade > wrote:
>
>
>>It has been sent.
>>
>>Dan wrote:
>>
>>>Yes.
>>>
>>>dsfh at
>>>cox.net
>>>
>>>Sam Spade wrote:
>>>
>>>
>>>>Dan wrote:
>>>>
>>>>
>>>>>I suppose I was more interested in MIAs then, however I'd take any MVA
>>>>>info you have (specifically interested in PHX)
>>>>
>>>>Is this a valid email address?
>>>
>
> Please post here also, or send a reference. The rest of us Arizonans are interested.
>
> thanks,
> Mike
It is not possible to post a binary file here.

[Sam Spade]

Mike Adams wrote:

> Sam Spade > wrote:
>
>
>>It has been sent.
>>
>>Dan wrote:
>>
>>>Yes.
>>>
>>>dsfh at
>>>cox.net
>>>
>>>Sam Spade wrote:
>>>
>>>
>>>>Dan wrote:
>>>>
>>>>
>>>>>I suppose I was more interested in MIAs then, however I'd take any MVA
>>>>>info you have (specifically interested in PHX)
>>>>
>>>>Is this a valid email address?
>>>
>
> Please post here also, or send a reference. The rest of us Arizonans are interested.
>
> thanks,
> Mike

I uploaded it to:
alt.binaries.pictures.aviation

Title: PHX MAV (I made a typo in the, which Steve will tell you makes
it all invalid. ;-)

It is an Acrobat file.

[Mike Adams[_2_]]

Sam Spade > wrote:

> I uploaded it to:
> alt.binaries.pictures.aviation
>

Got it. Thanks.

Mike

[Robert M. Gary]

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

[Sam Spade]

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

[Newps]

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.

[Dan[_1_]]

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.

[Sam Spade]

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.

[Sam Spade]

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.

[Steven P. McNicoll[_1_]]

"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]

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.

[Sam Spade]

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.
>
>

[Steven P. McNicoll[_1_]]

"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.

[Steven P. McNicoll[_1_]]

"Sam Spade" > wrote in message
news:DP9tg.659$_M.553@fed1read04...
>
> Also, his point is well taken.

His point was incorrect.


>
> 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.
>

Irrelevant. You can only be worked by one facility at any time.

[Robert M. Gary]

Steven P. McNicoll wrote:
> Distance from antenna has nothing to do with MIAs. MIAs and MVAs are
> established without regard to distance from antenna.

Are you going to leave us in suspense? What is the MIA based on?

I'm not a controller so I don't know what you call it but I know that
when Lemoore approach is open I can fly over Harris Ranch IFR at 2,000
feet but when they close and Oakland center takes over the min is 8000
feet (quite a difference).

-Robert

[Sam Spade]

Steven P. McNicoll wrote:
> "Sam Spade" > wrote in message
> news:DP9tg.659$_M.553@fed1read04...
>
>>Also, his point is well taken.
>
>
> His point was incorrect.
>
>
>
>>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.
>>
>
>
> Irrelevant. You can only be worked by one facility at any time.
>
>
Yes, but two (or more) radar sites can serve a facility.

[Steven P. McNicoll[_1_]]

"Sam Spade" > wrote in message
news:BNbtg.661$_M.236@fed1read04...
>
> Yes, but two (or more) radar sites can serve a facility.
>

But two (or more) radar sites have no effect on a facility's MIA or MVA.

[Sam Spade]

Steven P. McNicoll wrote:

> "Sam Spade" > wrote in message
> news:BNbtg.661$_M.236@fed1read04...
>
>>Yes, but two (or more) radar sites can serve a facility.
>>
>
>
> But two (or more) radar sites have no effect on a facility's MIA or MVA.
>
>
Check out the PDF I uploaded to aviation binaries for the Palm Springs area.

[Sam Spade]

Robert M. Gary wrote:

> Steven P. McNicoll wrote:
>
>>Distance from antenna has nothing to do with MIAs. MIAs and MVAs are
>>established without regard to distance from antenna.
>
>
> Are you going to leave us in suspense? What is the MIA based on?
>
> I'm not a controller so I don't know what you call it but I know that
> when Lemoore approach is open I can fly over Harris Ranch IFR at 2,000
> feet but when they close and Oakland center takes over the min is 8000
> feet (quite a difference).
>
> -Robert
>
Most controllers do not design MIAs or MVAs. It is a specialty, which
requires airspace training beyond what is required to control traffic.

Steve is commenting in the abstract, rather than from real-world practices.

In alt.binaries.pictures.aviation I have posted a two page PDF that
shows both the MIAs (LA Center) and MVAs (Palm Springs TRACON) for an
identical portion of the airspace around Palm Springs.

The title of the posting is:

Palm Springs MIAs MVAs for IFR Group

The file is:

PSP MIAs and MVAs.pdf

Note in particular how much higher the MIA is for the valley floor.
This is because the specialist at Los Angeles Center know they have no
radar coverage down in that valley, thus the MIA design in this case
takes into substantial consideration the center's radar coverage in that
area.

It's a facility call to design MIAs in accordance with what they
consider to be the best fit for their airspace and terrain.

[Steven P. McNicoll[_1_]]

"Sam Spade" > wrote in message
news:xlctg.663$_M.332@fed1read04...
>
> Check out the PDF I uploaded to aviation binaries for the Palm Springs
> area.
>

Check it for what?

[Sam Spade]

Steven P. McNicoll wrote:
> "Sam Spade" > wrote in message
> news:xlctg.663$_M.332@fed1read04...
>
>>Check out the PDF I uploaded to aviation binaries for the Palm Springs
>>area.
>>
>
>
> Check it for what?
>
>
To see how much higher the MIAs are over the Palm Springs valley than
the MVAs.

[Newps]

Sam Spade wrote:

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

That's exactly where Salt Lake has the advantage on us, in the
mountains. Several thousand feet.

[Steven P. McNicoll[_1_]]

"Robert M. Gary" > wrote in message
ps.com...
>
> Are you going to leave us in suspense? What is the MIA based on?
>

MIAs are established in accordance with FAA Order 7210.37 En Route Minimum
IFR Altitude Sector Charts:



1. PURPOSE. Establishes amended procedures and criteria to develop MIA
sector charts for en route air traffic facilities.

2. DISTRIBUTION. Distributed to offices in Washington and Regional
headquarters, FAA Technical Center, Mike Monroney Aeronautical Center, air
traffic facilities, and Flight Inspection Field Offices.

3. CANCELLATION. Order 7210. 37A, dated March 7, 1980, is canceled. Joint
AFO-700/AAT-300 letter dated May 18, 1981, subject: En Route IFR Altitude
Sector Charts is canceled.

4. ACTION. Each air route traffic control center shall develop and
implement MIA sector charts using these procedures/criteria. Use Appendix 1
for facility status accounting and FIFO chart data review and approval.

5. MIA SECTOR CHARTS. MIA sector charts provide minimum IFR altitude
information for off-airway operations. MIA charts and associated clearance
altitudes are established without respect to normal radar coverage within
the area concerned. It is the controllers responsibility to determine if a
target return is adequate for radar control.

6. MIA SECTOR CHARTING CRITERIA. Establish MIA's with respect to all
surface
areas in delegated airspace as well as adjacent areas where control
responsibility is assumed because of early handoff or track initiation.
Divide the MIA charts into areas (referred to as MIA areas) as required to
accommodate different MIA's without respect to sector or facility
boundaries, as follows:

a. Establish the lateral boundaries of MIA areas:

(1) Using sectional aeronautical charts. The Maximum Elevation
Figures (MEF)
located in sectional quads may be used as a guide to establishing the MIA.

(2) Using geographical points defined by latitude and longitude to
the nearest second.

(3) Addressing operational requirements (i.e., normal traffic
flows, minimum en route altitudes (MEA) where lower than MIA), where
possible.

(4) A minimum of 5 nautical miles (NM) from the terrain/obstruction
used to establish the MIA for each MIA area, except where such
terrain/obstruction is located within 5NM of the lateral limits of an
airway, (or Part 95 direct route or documented non-Part 95 off-airway
route). For the latter, the limits of the airway (or route) will serve as
the associated MIA area boundary.

b. Establish the MIA for each area:

(1) By applying the appropriate mountainous or nonmountainous
obstruction
clearance criteria per Orders 8260.19 and 8260.3. Round the altitudes to
the nearest 100-foot increment.

(2) Within controlled airspace, by ensuring that the depicted MIA
is at least 300 feet above the floor of controlled airspace.

(3) Within uncontrolled airspace, by applying the appropriate
mountainous/nonmountainous clearance criteria without respect to overlying
controlled airspace in paragraph 6.b.(2) above.

Note. - The existence of a MIA in uncontrolled airspace relates to
terrain/obstruction clearance only, it does not constitute authority to
conduct IFR operations within uncontrolled airspace.

Reference. - 7110.65 - Uncontrolled Airspace and Application (Vectoring).

(4) Where an airway MEA is below an adjacent MIA area altitude, it
may be necessary to adapt the airway or an appropriate block of airspace
containing the airway as a separate MIA area to preclude E-MSAW nuisance
alerts. MEA's shall be obtained from en route low altitude charts and thus
become the adopted E-MSAW alerting altitude for an MIA area that defines an
airway. Since radar vectoring along an airway, or radial thereof, requires
greater lateral obstruction/terrain clearance than would normally be imposed
on a flight that has been specifically cleared via the airway, an
independent
check must be made to ensure that vectoring within an MIA defined airway
would not result in reduction of the appropriate clearance criteria.

c. Where small contiguous MIA areas with different altitudes do not
serve an operational need, combine them using the highest applicable MIA.

d. To avoid a large MIA area with an excessively high altitude due to
an isolated prominent obstruction, enclose the obstruction within its own
MIA area. When the isolated obstruction is terrain, evaluate related slopes
or ridge lines to ensure appropriate obstruction clearance criteria is
applied.

e. Each MIA area shall have the terrain/obstruction that constitutes
the basis for the MIA, in addition to its elevation, highlighted in such a
manner that would allow it to be easily found by a controller, but not
clutter the MIA chart. Large MIA areas with irregular or precipitous or
multiple obstructions may have more than one elevation highlighted.

f. MIA areas should be labeled with respect to the E-MSAW area
identification criteria. The identifier has three letters and two digits
(LLLdd), to identify areas relative to significant geographical points or
fixes.

7. MIA SECTOR CHART DISPLAY. Applicable portions of the facility's MIA
chart shall be displayed at each low altitude sector. This MIA sector chart
shall accommodate operational requirements. Air traffic managers shall
determine the appropriate method of displaying this information at the
sector. MIA's shall be displayed with each associated MIA area. For an
airway adapted as a MIA area, (reference paragraph 6.b.(4)):

a. If the MEA is sufficient for vectoring, the MIA and the MEA shall be
depicted as one altitude for that area.

b. If a higher altitude is required for vectoring, then both the
adopted E-MSAW alerting altitude (MEA) and the vectoring altitude shall be
displayed on the MIA sector chart, associated with the proper area, and
separated by a slash (i.e., 90/70). Each sector chart or facility directive
shall contain an explanation of these split altitudes to the effect that:

(1) The higher altitude on the left of the slash is the appropriate
altitude for off-airway operations (radar vectoring).

(2) The lower altitude to the right of the slash is the adopted
E-MSAW alerting altitude.

8. MIA SECTOR CHART PROCESSING. Process MIA charts and altitude reduction
requests per Order 8260.3 criteria as follows:

a. Draw MIA sector charts directly on current sectional charts.

b. Prepare MIA sector chart and chart data record in duplicate.
Indicate amount of obstacle clearance reduction in ALT ADJ (altitude
adjustment) column. This column is also used to document the difference in
required altitude and round-off altitude. Use REMARKS column for
explanation.

c. Forward charts and chart data records to the FIFO for certification
and annual review. One copy of each chart and chart data record with the
FIFO manager's signature will be returned to the facility.

d. Monitor available sources including the weekly National Flight Data
Digest (NFDD) pertaining to construction notices that may affect specific
MIA areas. When needed, revise the affected charts.

e. Verify that the altitude information adapted in the NAS E-MSAW
polygons agree with the MIA sector charts.



>
> I'm not a controller so I don't know what you call it but I know that
> when Lemoore approach is open I can fly over Harris Ranch IFR at 2,000
> feet but when they close and Oakland center takes over the min is 8000
> feet (quite a difference).
>

That may not be due to the MIA. What's your route? If you're operating
off-airways and beyond normal usable navaid limits radar monitoring must be
provided. If 8000 is required to remain within radar contact with Oakland
then 8000 becomes the minimum altitude even if the MIA is significantly
lower.

[Steven P. McNicoll[_1_]]

"Sam Spade" > wrote in message
news:nrctg.664$_M.186@fed1read04...
>
> Most controllers do not design MIAs or MVAs. It is a specialty, which
> requires airspace training beyond what is required to control traffic.
>
> Steve is commenting in the abstract, rather than from real-world
> practices.
>
> In alt.binaries.pictures.aviation I have posted a two page PDF that shows
> both the MIAs (LA Center) and MVAs (Palm Springs TRACON) for an identical
> portion of the airspace around Palm Springs.
>
> The title of the posting is:
>
> Palm Springs MIAs MVAs for IFR Group
>
> The file is:
>
> PSP MIAs and MVAs.pdf
>
> Note in particular how much higher the MIA is for the valley floor. This
> is because the specialist at Los Angeles Center know they have no radar
> coverage down in that valley, thus the MIA design in this case takes into
> substantial consideration the center's radar coverage in that area.
>
> It's a facility call to design MIAs in accordance with what they consider
> to be the best fit for their airspace and terrain.
>

What do you base that on? FAA Order 7210.3 says MVAs are established
irrespective of the flight-checked radar coverage, that they are based on
obstruction clearance criteria only. FAA Order 7210.37 says MIAs are to be
established without respect to normal radar coverage. Have these orders
been rescinded?

[Steven P. McNicoll[_1_]]

"Sam Spade" > wrote in message
news:_Actg.665$_M.641@fed1read04...
>
> To see how much higher the MIAs are over the Palm Springs valley than the
> MVAs.
>

Why? What's your point?

[Sam Spade]

Steven P. McNicoll wrote:
> "Sam Spade" > wrote in message
> news:nrctg.664$_M.186@fed1read04...
>
>>Most controllers do not design MIAs or MVAs. It is a specialty, which
>>requires airspace training beyond what is required to control traffic.
>>
>>Steve is commenting in the abstract, rather than from real-world
>>practices.
>>
>>In alt.binaries.pictures.aviation I have posted a two page PDF that shows
>>both the MIAs (LA Center) and MVAs (Palm Springs TRACON) for an identical
>>portion of the airspace around Palm Springs.
>>
>>The title of the posting is:
>>
>>Palm Springs MIAs MVAs for IFR Group
>>
>>The file is:
>>
>>PSP MIAs and MVAs.pdf
>>
>>Note in particular how much higher the MIA is for the valley floor. This
>>is because the specialist at Los Angeles Center know they have no radar
>>coverage down in that valley, thus the MIA design in this case takes into
>>substantial consideration the center's radar coverage in that area.
>>
>>It's a facility call to design MIAs in accordance with what they consider
>>to be the best fit for their airspace and terrain.
>>
>
>
> What do you base that on? FAA Order 7210.3 says MVAs are established
> irrespective of the flight-checked radar coverage, that they are based on
> obstruction clearance criteria only. FAA Order 7210.37 says MIAs are to be
> established without respect to normal radar coverage. Have these orders
> been rescinded?
>
>
No, the orders are guidance, but no one is going to criticize a center
for using radar coverage as a floor in a terrain-laden area like the
Palm Springs area.

The MVA and MIA charts I posted a couple of months ago for that area
made that quite clear.

[Sam Spade]

Steven P. McNicoll wrote:

> "Sam Spade" > wrote in message
> news:_Actg.665$_M.641@fed1read04...
>
>>To see how much higher the MIAs are over the Palm Springs valley than the
>>MVAs.
>>
>
>
> Why? What's your point?
>
>
That obstacle clearance was not the driving factor for ZLA's MIAs in the
Palm Springs area; center radar coverage was.

[Steven P. McNicoll[_1_]]

"Sam Spade" > wrote in message
...
>
> No, the orders are guidance, but no one is going to criticize a center for
> using radar coverage as a floor in a terrain-laden area like the Palm
> Springs area.
>

FAA orders are guidance? They're not mandatory for those affected? What in
the wide, wide world of sports do you base that on?

Why wouldn't someone who knows how it's supposed to be done criticize a
center for doing it improperly?


>
> The MVA and MIA charts I posted a couple of months ago for that area made
> that quite clear.
>

Made what quite clear? That FAA orders are only guidance material, or that
no one is going to criticize a center for using radar coverage as a floor in
a terrain-laden area like the Palm Springs area?

[Steven P. McNicoll[_1_]]

"Sam Spade" > wrote in message
...
>
> That obstacle clearance was not the driving factor for ZLA's MIAs in the
> Palm Springs area; center radar coverage was.
>

How can you make that conclusion? Based on what you posted all we can know
for certain is at least one of the maps was made improperly.

[Sam Spade]

Steven P. McNicoll wrote:
> "Sam Spade" > wrote in message
> ...
>
>>That obstacle clearance was not the driving factor for ZLA's MIAs in the
>>Palm Springs area; center radar coverage was.
>>
>
>
> How can you make that conclusion? Based on what you posted all we can know
> for certain is at least one of the maps was made improperly.
>
>
You should let the Western-Pacific Region know that. That seems to be
the right thing for an FAA employee to do.