Definition
Controlled airspace that is not Class A, B, C, or D. Class E airspace exists to provide air traffic control service to instrument flight rules (IFR) traffic and supports the transition between the terminal environment and the en route structure. It typically begins at 700 feet or 1,200 feet above ground level (or another designated altitude) and extends up to, but not including, 18,000 feet mean sea level, with airspace above flight level 600 also classified as Class E.
Plain English
A general type of controlled airspace that fills in the gaps between the busier, more tightly controlled airspaces around big airports and the high-altitude airspace used by airliners. It is the most common kind of controlled airspace pilots fly through.
Context Anchor
Pilots encounter CEAS in airspace descriptions, chart notes, and NOTAM contractions that describe changes or conditions affecting Class E airspace.
Derivation
CEAS is built from Class E AirSpace. The letter E is just the assigned category in the airspace system; it does not stand for another word.
Why Pilots Care
Knowing Class E helps pilots determine when radio calls are required and what weather minimums apply for visual flight.
Intuition Check
Do not assume Class E means empty or uncontrolled. It is controlled airspace, but it usually has fewer entry requirements for visual flight than Classes A, B, C, or D.
Example Sentence 1
After departing the Class D airspace, the pilot climbed into Class E airspace and continued the cross-country flight.
Example Sentence 2
The pilot requested an instrument clearance while operating in Class E airspace near the non-towered airport.