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Greg Arehart
09-07-2014, 11:27 AM
So I've been planning a flight from Phoenix area to western Colorado, which goes near the far east end of the Grand Canyon. I'm looking at the chart (Las Vegas sectional) on Skyvector and at the NE end of the canyon near Page, AZ there is a funky airspace indicated by a black outline that looks a lot like the boundaries of Class E airspace, except it is black. The area is very narrow and linear (actually 2 areas) and no explanation on my older (2010) sectional. I also had a look at the Grand Canyon special VFR chart, and the areas are not marked on that chart at all. And I looked at the FAA Aeronautical Chart User's Guide online, and don't see what this is in there either.

So, any knowledge of what this is?

Greg

JDA_BTR
09-07-2014, 11:45 AM
I don't know but I'm curious now too. When I look at the IFR charts the area coincides with the line demarcating the boundary between the Las Vegas and Denver ATCSS?...

jrs14855
09-07-2014, 11:59 AM
Similar markings on ABQ chart near Santa Fe and SW of ABQ

JDA_BTR
09-07-2014, 12:20 PM
I don't think the two shaded areas on the sectional are covered by the GCN chart. And the ones around Santa Fe and Albequerque aren't labelled special either. Hmmmmm.. The closest thing I know like that is a TSRA, but this doesn't look quite like that.

mburch
09-07-2014, 12:33 PM
I believe what you're seeing here is the edge of Class E airspace that abuts Class G. If you look in the vicinity of KLMT, you can see a lot of this type of airspace. If you toggle over to the IFR low chart, you'll see that the same areas are shaded brown, which indicates uncontrolled airspace.

On VFR charts these lines are supposed to be shaded blue, not grey, so maybe there was a printing problem or a color translation issue with Skyvector. Or we all need to calibrate our monitors...

mcb

az_gila
09-07-2014, 12:33 PM
Yes... a TRSA does not have the grey area shaded.

It didn't make the User Guide either -

http://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/aero_guide/media/Chart_Users_Guide_12thEd.pdf

rv699jb
09-07-2014, 05:30 PM
The Magenta shading points out the "E" airspace drops to 700 feet above the ground, rather than the 1200 feet adjacent to it. The Magenta shading can be assumed to continue across the map, until it meets another Magenta line. On older VFR sectional maps, there used to be a blue shaded area adjacent to and touching the magenta shading going in the other direction. This deplicted 1200 feet. You could also assume the blue shading continued across the map until it contacted another blue shading, or another type airspace marking. Because it was always assumed that the blue lines butted up against Magenta lines, and that E airspace started at 1200 feet, unless shown different (magenta lines for one), the blue shading was removed from the charts. So, assume there is now that grey shading against all magenta lines. Now, we have that grey line (used to be blue), showing 1200 feet around all airports just outside the magenta line, but just not there because it is assumed. However, the specific spot you are talking about 'is' different. E airspace does not go over that sliver of land between the grey lines. At the grey line right west of Page, the E airspace is 1200 feet. Right at the darkest part of the first grey line, the E airspace goes vertical to the next airspace above it (in this case to 14,500 feet). Then, between the two grey lines, you have G airspace from the ground up to 14,500 feet! You can also see this same airspace marked around Prescott. Away from the dark grey line is 1200 feet floor of E airspace, and inside it the G airspace goes vertical from the ground to the next airspace above. I don't think you will find any of this G airspace from the surface to 14,500 feet east of the Rockies. A trivia question: Can you fly IFR in this airspace (G), between the dark grey lines, say at 9000 feet, in the clouds, without a IFR Clearance, or talking to Center on a radio?

Good questions!

Jim Baker
CFI-IA
RV-6

n5lp
09-07-2014, 05:50 PM
...A trivia question: Can you fly IFR in this airspace (G), between the dark grey lines, say at 9000 feet, in the clouds, without a IFR Clearance, or talking to Center on a radio?

Good questions!

Jim Baker
CFI-IA
RV-6

Instrument rated and equipped, yes. That is the main reason for IFR altitudes as altitudes are assigned in controlled airspace. When I was with FAA I knew of 135 operators that would fly IFR without flight plans or clearances (in very remote areas).

az_gila
09-07-2014, 05:54 PM
The Magenta shading points out the "E" airspace drops to 700 feet above the ground, rather than the 1200 feet adjacent to it. The Magenta shading can be assumed to continue across the map, until it meets another Magenta line. On older VFR sectional maps, there used to be a blue shaded area adjacent to and touching the magenta shading going in the other direction. This deplicted 1200 feet. You could also assume the blue shading continued across the map until it contacted another blue shading, or another type airspace marking. Because it was always assumed that the blue lines butted up against Magenta lines, and that E airspace started at 1200 feet, unless shown different (magenta lines for one), the blue shading was removed from the charts. So, assume there is now that grey shading against all magenta lines. Now, we have that grey line (used to be blue), showing 1200 feet around all airports just outside the magenta line, but just not there because it is assumed. However, the specific spot you are talking about 'is' different. E airspace does not go over that sliver of land between the grey lines. At the grey line right west of Page, the E airspace is 1200 feet. Right at the darkest part of the first grey line, the E airspace goes vertical to the next airspace above it (in this case to 14,500 feet). Then, between the two grey lines, you have G airspace from the ground up to 14,500 feet! You can also see this same airspace marked around Prescott. Away from the dark grey line is 1200 feet floor of E airspace, and inside it the G airspace goes vertical from the ground to the next airspace above. I don't think you will find any of this G airspace from the surface to 14,500 feet east of the Rockies. A trivia question: Can you fly IFR in this airspace (G), between the dark grey lines, say at 9000 feet, in the clouds, without a IFR Clearance, or talking to Center on a radio?

Good questions!

Jim Baker
CFI-IA
RV-6

So the official FAA Charts Users guide has missing information even though it is the Oct 2013 edition?

BobTurner
09-07-2014, 06:04 PM
The explanation that it is class G makes sense if you change 'blue' to 'gray' in the chart symbol index. But when did that happen?

Greg Arehart
09-07-2014, 06:43 PM
I believe what you're seeing here is the edge of Class E airspace that abuts Class G. If you look in the vicinity of KLMT, you can see a lot of this type of airspace. If you toggle over to the IFR low chart, you'll see that the same areas are shaded brown, which indicates uncontrolled airspace.

On VFR charts these lines are supposed to be shaded blue, not grey, so maybe there was a printing problem or a color translation issue with Skyvector. Or we all need to calibrate our monitors...

mcb

I'm going to go with this explanation for now. But it's a bit of an odd shape (at least the one near Page AZ) - such a tiny wedge of space.

Nothing like spending Sunday looking at charts!

Greg

PCHunt
09-07-2014, 08:19 PM
If you can find a really old, say 1960's sectional, you will find large areas of uncontrolled airspace in the western US.

The small triangles are just what is left over after all the airways and other airspace became "controlled" airspace. [old terminology].

The VFR wx requirements are just about the only thing that changes in that airspace. (and yes, you can legally fly IFR [technically IMC] in that airspace without a clearance or comm. But you can't go very far!! :rolleyes:

JDA_BTR
09-07-2014, 11:35 PM
So V293 is cutting a path through a sliver of uncontrolled airspace west of Page right on the border of the Denver/LasVegas approach areas?.. weird vestige!

BobTurner
09-08-2014, 12:57 AM
So V293 is cutting a path through a sliver of uncontrolled airspace west of Page right on the border of the Denver/LasVegas approach areas?.. weird vestige!

I do not think so. Northwest of Page V293 has a dog leg to avoid the uncontrolled airspace; southwest it misses it, too.