(b) A Class E surface area may also be designated to accommodate part-time operations at a Class C or
Class D airspace location (for example, those periods when the control tower is not in operation).
(c) Pilots should refer to the airport page in the applicable Chart Supplement U.S. for surface area status
information.
2. Extension to a surface area. Class E airspace may be designated as extensions to Class B, Class C,
Class D, and Class E surface areas. Class E airspace extensions begin at the surface and extend up to the overlying
controlled airspace. The extensions provide controlled airspace to contain standard instrument approach
procedures without imposing a communications requirement on pilots operating under VFR. Surface arerrival
extensions become part of the surface arend are in effect during the same times as the surface area.
NOTE-
When a Class C or Class D surface area is not in effect continuously (for example, where a control tower only operates
part-time), the surface areirspace will change to either a Class E surface area or Class G airspace. In such cases, the
"Airspace" entry for the airport in the Chart Supplement U.S. will state "other times Class E" or "other times Class G."
When a part-time surface area changes to Class E airspace, the Class E arrival extensions will remain in effect as Class
E airspace. If a part"time Class C, Class D, or Class E surface area becomes Class G airspace, the arrival extensions will
change to Class G at the same time.

3. Airspace used for transition. Class E airspace areas may be designated for transitioning aircraft
to/from the terminal or en route environment.
(a) Class E transition areas extend upward from either 700 feet AGL (shown as magenta vignette on
sectional charts) or 1,200 feet AGL (blue vignette) and are designated for airports with an approved instrument
procedure.
(b) The 700-foot/1200-foot AGL Class E airspace transition areas remain in effect continuously,
regardless of airport operating hours or surface area status.
NOTE-
Do not confuse the 700-foot and 1200-foot Class E transition areas with surface areas or surface area extensions.

4. En Route Domestic Areas. There are Class E airspace areas that extend upward from a specified
altitude and are en route domestic airspace areas that provide controlled airspace in those areas where there is
a requirement to provide IFR en route ATC services but the Federal airway system is inadequate.
5. Federal Airways and Low-Altitude RNAV Routes. Federal airways and low-altitude RNAV routes are
Class E airspace areas and, unless otherwise specified, extend upward from 1,200 feet AGL to, but not
including,18,000 feet MSL.
(a) Federal airways consist of Low/Medium Frequency (L/MF) airways (colored Federal airways) and
VOR Federal airways.
(1) L/MF airways are based on non-directional beacons (NDB) and are identified as green, red, amber,
or blue.
(2) VOR Federal airways are based on VOR/VORTAC facilities and are identified by a "V" prefix.
(b) Low-altitude RNAV routes consist of T-routes and helicopter RNAV routes (TK-routes).
NOTE-
See AIM paragraph 5-3-4, Airways and Route Systems, for more details and charting information.

6. Offshore Airspace Areas. There are Class E airspace areas that extend upward from a specified altitude
to, but not including, 18,000 feet MSL and are designated as offshore airspace areas. These areas provide
controlled airspace beyond 12 miles from the coast of the U.S. in those areas where there is a requirement to
provide IFR en route ATC services and within which the U.S. is applying domestic procedures.
f. Separation for VFR Aircraft. No separation services are provided to VFR aircraft.

Controlled Airspace

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