Charting controlled airspace
Answered By AOPA
Does anyone know what year the FAA changed the way they depicted controlled airspace from 1200 to 700 feet? Here is an example of an older depiction.

2 Replies
AOPA Staff Answer
Hi Andy,

No luck on finding the information for you. Do you know when the example you used was printed? You can always email the charting office with your question, they may have an answer for you. You can make aeronautical inquiries with the charting office by clinking on the "create a new Aeronautical Inquiry" button on this page.

Very old aeronautical charts are hard to come by because they are typically thrown away once they're out of date. The Library of Congress does have electronic records of older aeronautical charts, but the series is incomplete, a lot of them aren't available online and it's difficult to go through them when you don't have a starting date. You can find that listing here. There is also a NOAA historical chart website, where you can select aeronautical charts as an option, plenty of charts there as well.

About 1993, possibly done in conjunction with the change to ICAO lettered airspace classes.

I have a June 25, 1992, Green Bay sectional that indicates blue vignette means "Floor 1200 feet above surface".  Airspace is depicted as in your attachment. 

The June 23, 1994, Green Bay sectional shows "Class E Airspace with floor 1200 ft. or greater above surface that abuts Class G Airspace."  Magenta vignette stands alone where the adjacent Class E airspace has a floor 1200 AGL.