Mxsmanic wrote:
There are some mysteries that I've encountered while learning to read
VFR charts:

1. I see airports with dashed cyan circles around them that I presume
indicate Class D airspace (based on the chart legend). However, the
circles are not always the same size, and I don't see any indication
of their radii; how do I determine how far out the Class D circle
extends (short of measuring it by hand)? Also, is there a convention
for the center of the Class D circle (tower, or whatever?)? They
don't seem to be centered on anything easily identifiable.

The nominal diameter is 4.3 NM (5 SM). There
may be extensions either as class D or class E surface area that
accomodate the instrumetn approaches. They're centered on the
airport reference point.


2. The legend doesn't appear to explain lines that consist of a solid
cyan line with cyan dots inside. It seems to outline things like
wildlife refuges or parks and stuff like that. Is this just an extra
line style used for things that don't otherwise have line styles
assigned, or what? Are there any restrictions or other things to know
about spaces enclosed by these lines, or are they for information
only?


Symbols are explained more in the Aeronautical Chart User's Guide.
http://www.naco.faa.gov/index.asp?xm...ine/aero_guide

The blue line with the dots indicates a conservation area (wilelife
refuge, national park ,etc.).

Pilots are requested to stay 2000' above these (but it's not
mandatory).

3. I'm confused about Class E airspace. If I understand correctly,
the absence of any other indication on the chart means that Class E
starts at 1200' AGL, and extends to 18,000' MSL. If the shaded purple
border encloses an area, it's Class E starting at 700' AGL and still
extending to 18,000' MSL. If it's a shaded cyan border, it means ...
Class E starts at 1200' AGL and extends to 18,000' MSL?? (The chart
says "abuts Class G," but I'm not sure what they mean.)

Originally there was a lot less controlled airspace than there is
now. If you're out in parts of the country which is much more
desolate you'll fine the 1200' floors under airway, and the 700'
floors around airports that have instrument approaches that don't
have class E to the ground (transition areas). In most places
now, the 1200 stuff pretty much just overlaps everything and there
are magenta vignettes to take it down to 700'.

Originally, the magenta vignette was abutted with a blue vignette
showing the step up to 1200. Now they don't show the blue vignette
when it's bumping up against 700' or surface area boundaries, only
when it bumps up against uncontrolled airspace.



4. The cyan chain-link Class E border confuses me. Which side is
inside the Class E? The altitude is the floor of the Class E and it
still extends to 18,000' MSL, right? If there are different altitudes
on each side of the chain link, what does that mean, and where do I
look for the other border of the airspace? For example, just west of
Buckeye on the Phoenix sectional, there are chain links and stuff all
over the place, and I'm having trouble figuring out what the floors
are and where. Around Western Sky airport (W 113° 40' N 33° 46'
roughly), I see the shaded cyan border for Class E at 1200' AGL, but
in that area I see 7000 MSL, and a chain link on the right and bottom.
There are chain links next to airways, too. I don't know which
altitude applies where.

The zig/zag class E borders are used only in bizarre mountainous
area. The side with the text is the non-standard controlled
airspace floor.