When did the phrase "Class E" or "Class E airspace" first appear on the legend of US VFR sectional charts, to identify the meaning of the thin dashed magenta line? I'd like to narrow down the date as precisely as possible. Currently I'm aware that this phrase DID appear on the legend of a sectional chart (Hawaiian Islands) effective November 11, 1993, and did NOT appear on the legend of a sectional chart effective August 19 1993. Please post the "effective date" of any US VFR sectional chart that you are aware of before November 11 1993 in which the phrase "Class E" or "Class E airspace" does appear on the legend, or the "effective date" of any US VFR sectional chart that you aware of after August 19 1993 in which the phrase "Class E" or "Class E airspace" does not appear on the legend.

Basically this question is just asking when the current "alphabet" system of airspace classification first appeared on US VFR sectional charts-- presumably the terms "Class A", "Class B", "Class C", "Class D", and "Class E" were all introduced at the same time.

When answering this question please disregard any reference to foreign (e.g. Canadian) airspace on the legend of the US VFR sectional chart-- the transition to the "alphabet" system of airspace classification may not have been simultanous between the US and all bordering countries.

  • $\begingroup$ It was in place in the US already when I started flying in April of 1994. But hadn't been for very long at that point. Long enough tho to make into the text books. $\endgroup$
    – CrossRoads
    Commented Nov 1, 2018 at 12:21
  • $\begingroup$ The date will an AIRAC cycle date. Changes to airspace and procedures are only introduced on cycles of 28 days. The current AIRAC cycle started at 11 October 2018, the next will be 08 November 2018. In 1993 this gives the following options after 19 August 1993: 16 September, 14 October, 11 November. So you can now narrow your search to these three dates. $\endgroup$
    – DeltaLima
    Commented Nov 1, 2018 at 15:20
  • $\begingroup$ That is very helpful. Looks like it had to be either the September date or the October date, and seems most likely to have been the September date based on one of the answers below. $\endgroup$ Commented Nov 1, 2018 at 15:25

2 Answers 2


According to this AOPA article, the change was made in Sept, 1993

In a move to simplify airspace classification, the FAA will rename the different airspace categories on Sept. 16, 1993. In order to fall in line with ICAO (International Civil Aviation Organization) practices, it will replace descriptive titles, such as Terminal Control Area, with alphabetical designators, such as Class B Airspace. This change will be phased in gradually. Charts and references will carry both designations until pilots get used to the transition.


And some more background

A Brief History of Aeronautical Charting

To understand the change that GIS has brought to the National Geospatial-Intelligence Agency (NGA), it is helpful to be familiar with the history of aeronautical charting.

Shortly after the Wright brothers made their historic first flights, the skies began to fill with aircraft. Visibility was the key navigational tool at that time. Aircraft were limited to short flights in clear weather and used transportation routes to navigate by, flying low to the railroads during reduced visibility. Early pilots began making personal notes to help them navigate to and land at increasingly distant airports, and enterprising pilots sold these notes to other pilots, but air travel remained limited by visibility.

In the 1930s, radio technology made it possible for pilots to navigate farther distances through unfamiliar surroundings in reduced visibility. In 1941, the first instrument approach and landing charts were developed, serving pilots with the need to land in low visibility.

By this time, aviation was a matter of interest worldwide. Many organizations began drafting standards for aviation-related maps, charts, and information. During World War II, the demand for charts increased dramatically. By 1943, production had increased from around 500,000 per year to more than 11 million. The U.S. Army and Navy air forces each built their own custom charts to fit their wartime needs.

By the end of the war, it was clear that standardized products and symbology were needed to support international air travel. The following years saw the establishment and maturity of many of the aeronautical- and aviation-related agencies and associations that we see today, such as the U.S. Federal Aviation Administration and the United Nations International Civil Aviation Organization (ICAO), each mandated to ensure the safe, efficient, and orderly evolution of international civil aviation.

Today, these organizations and others drive the look and feel of aviation products worldwide. They have also mandated an update cycle to ensure that all aircraft are flying on the same data. Depending on the region of the world, this cycle is effective every 28 days or multiples of 28 days. It is easy to see how a map of the world's airports and airways, updated every 28 days and limited by international standards, can become a huge challenge. This challenge is the mission of NGA's Aeronautical Division.


  • $\begingroup$ PS I would really interested to know if anyone comes across a sectional chart on which the dashed magenta line is identified BOTH as "Class E" or "Class E airspace", AND as "Control Zone at airport without control tower and Control Zone extension without communications requirement" or something to that effect, It appears that this would have only happened-- if ever-- sometime after August 19 1993 and before November 11 1993. But, that's really a new question isn't it. $\endgroup$ Commented Nov 1, 2018 at 15:23
  • $\begingroup$ @quietflyer -Btw, I started as a CFI in 1974 and the only place where a SVFR clearance could be issued was in a "control zone" and this included control zone extensions (they looked just like the current class e surface area extensions do today). Control Zones would start from the surface and extend upward to the overlaying airspace. $\endgroup$
    – user22445
    Commented Nov 1, 2018 at 15:32
  • $\begingroup$ Well that is very interesting. Can give you give a specific airport or region where this was considered to be the case? Also it seems you might want to post your comment as answer to this related question -- aviation.stackexchange.com/questions/48106/… -- I see you were active in that discussion in comments but didn't post an answer. Even if it is superceded by later information it is an interesting data point. Anyway thanks for the note. $\endgroup$ Commented Nov 1, 2018 at 15:38
  • $\begingroup$ @quietflyer- Control Zones were all over the U.S., and were replaced (generally) by Class D airspace and Class E surface areas (and their extensions). Prior to 1993 "Airport Traffic Areas" (ATA) were 5 sm up to 2500 agl (best of my memory). The ATA's were not "controlled airspace" by definition. They were only "controlled airspace" if they were located inside a "Control Zone," which most were. $\endgroup$
    – user22445
    Commented Nov 1, 2018 at 15:45
  • $\begingroup$ Btw re "airport traffic areas" -- here is something I noticed while looking through old sectional charts etc -- "Also by that time (1974), an "Airport Traffic" area was a different thing from a "Control Zone", requiring radio communication with the tower for entry, with a smaller, standardized diameter and a much smaller, standardized vertical height." $\endgroup$ Commented Nov 1, 2018 at 16:13

As indicated by CrossRoads it was on September 16, 1993 that the airspace classification structure changed. The decision was made in 1991, as can be seen in the US Library of Congress: Federal Register: 56 Fed. Reg. 65415 (Dec. 17, 1991).


This final rule amends the Federal Aviation Regulations (FAR) to adopt certain recommendations of the National Airspace Review (NAR) concerning changes to regulations and procedures in regard to airspace classifications. These changes are intended to: (1) Simplify airspace designations; (2) achieve international commonality of airspace designations; (3) increase standardization of equipment requirements for operations in various classifications of airspace; (4) describe appropriate pilot certificate requirements, visual flight rules (VFR) visibility and distance from cloud rules, and air traffic services offered in each class of airspace; and (5) satisfy the responsibilities of the United States as a member of the International Civil Aviation Organization (ICAO). The final rule also amends the requirement for minimum distance from clouds in certain airspace areas and the requirements for communications with air traffic control (ATC) in certain airspace areas; eliminates airport radar service areas (ARSAs), control zones, and terminal control areas (TCAs) as airspace classifications; and eliminates the term "airport traffic area." The FAA believes simplified airspace classifications will reduce existing airspace complexity and thereby enhance safety.


These regulations become effective September 16, 1993, except that ...


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