Old Mountain West Sectional

[luvflyin]

Largely due to regulatory requirements (See FAR Part 73 and the FAA Order 7400.11 series ferinstance). The default is uncontrolled. The FAA goes through the regulatory process when creating, modifying, removing areas of controlled airspace. There is supposed to be a traffic and safety rationale. If you think of "controlled airspace" as airspace in which ATC has the authority to control traffic, and the basic idea that government interference should be minimal (yeah, I know), you can get a picture of the reason why this is the case.

So it's been done piecemeal through the years. There are leftovers although they get fewer and fewer. At some point, I expect there will be a final "cleanup" to get rid of the rest, except perhaps in some special use areas.

Almost all, if not all, went away with an Aeronautical Chart Bulletin effective 8 NOV 2018. It covered all the sky in Los Angeles Centers Airspace. See the Bulletins for the Grand Canyon, Las Vegas, Phoenix and San Francisco Sectionals in the Southwest Chart Supplement. Pages 393-401

 

[luvflyin]

The IFR regs require at least 2000 AGL in mountainous terrain. 91.177.

Don't forget 91.179. Sometimes it looks like you can do it because 1000/2000 AGL will be below overlying Controlled Airspace, but the requirement to Cruise at Cardinal Altitudes for direction of flight will put you up in it

 

[midlifeflyer]

Don't forget 91.179. Sometimes it looks like you can do it because 1000/2000 AGL will be below overlying Controlled Airspace, but the requirement to Cruise at Cardinal Altitudes for direction of flight will put you up in it

How could I ever forget 91.179?

Thanks for the suggestions. The problem with most remaining Class G abive 1200 is either the small size of the area or its proximity to special use airspace.