U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL AVIATION ADMINISTRATION

Part 4. Terminal and
En Route Airspace

Chapter 14. Designation of Airspace Classes

Section 1. General

14-1-1. PURPOSE

In addition to the policy guidelines and procedures detailed in Part 1. of this order, this part prescribes specific policies and procedures for managing terminal and en route airspace cases.

14-1-2. DEFINITIONS

a. CONTROLLED AIRSPACE. An airspace of defined dimensions within which ATC service is provided to IFR flights and to VFR flights in accordance with the airspace classification.

1. Controlled airspace is a generic term that covers Class A, Class B, Class C, Class D, and Class E airspace areas.

2. Controlled airspace is also that airspace within which all aircraft operators are subject to certain pilot qualifications, operating rules, and equipment requirements in 14 CFR part 91 (for specific operating requirements, please refer to 14 CFR part 91). For IFR operations in any class of controlled airspace, a pilot must file an IFR flight plan and receive an appropriate ATC clearance. Each Class B, Class C, and Class D airspace area designated for an airport contains at least one primary airport around which the airspace is designated (for specific designations and descriptions of the airspace classes, please refer to 14 CFR part 71).

3. Controlled airspace in the United States is designated as follows:

(a) CLASS A AIRSPACE AREA. Generally, that airspace from 18,000 feet MSL up to and including FL 600, including the airspace overlying the waters within 12 nautical miles (NM) of the coast of the 48 contiguous States and Alaska. Unless otherwise authorized, all persons must operate their aircraft under IFR.

(b) CLASS B AIRSPACE AREA. Generally, that airspace from the surface to 10,000 feet mean sea level (MSL) surrounding the nation's busiest airports in terms of airport operations or passenger enplanements. The configuration of each Class B airspace area is individually tailored and consists of a surface area and two or more layers, and is designed to contain all published instrument procedures. An ATC clearance is required for all aircraft to operate in the area, and all aircraft that are so cleared receive separation services within the airspace. The cloud clearance requirement for VFR operations is "clear of clouds."

(c) CLASS C AIRSPACE AREA. Generally, that airspace from the surface to 4,000 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower, are serviced by a radar approach control, and that have a certain number of IFR operations or passenger enplanements. Although the configuration of each Class C area is individually tailored, the airspace usually consists of a surface area with a 5 NM radius, an outer circle with a 10 NM radius that extends from no lower than 1,200 feet up to 4,000 feet above the airport elevation. Each person must establish two-way radio communications with the ATC facility providing air traffic services prior to entering the airspace and thereafter maintain those communications while within the airspace.

(d) CLASS D AIRSPACE AREA. Generally, that airspace from the surface to 2,500 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower. The configuration of each Class D airspace area is individually tailored and when instrument procedures are published, the airspace will normally be designed to contain the procedures. Arrival extensions for instrument approach procedures may be Class D or Class E airspace. Unless otherwise authorized, each person must establish two-way radio communications with the ATC facility providing air traffic services prior to entering the airspace and thereafter maintain those communications while in the airspace. No separation services are provided to VFR aircraft.

(e) CLASS E AIRSPACE AREA. Generally, if the airspace is not Class A, Class B, Class C, or Class D, and it is controlled airspace, it is Class E airspace. The types of Class E airspace areas are:

(1) Surface Area Designated for an Airport - When designated as a surface area for an airport, the airspace will be configured to contain all instrument procedures.

(2) Extension to a Surface Area - There are Class E airspace areas that serve as extensions to Class B, Class C, Class D, and Class E surface areas designated for an airport. Such airspace provides controlled airspace to contain standard instrument approach procedures without imposing a communications requirement on pilots operating under VFR.

(3) Airspace Used for Transition - There are Class E airspace areas beginning at either 700 or 1,200 feet AGL used to transition to/from the terminal or en route environment.

(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 - The Federal airways are Class E airspace areas and, unless otherwise specified, extend upward from 1,200 feet to, but not including, 18,000 feet MSL. The colored airways are green, red, amber, and blue. The VOR airways are classified as Domestic, Alaskan, and Hawaiian.

(6) Unless designated at a lower altitude, Class E airspace begins at 14,500 feet MSL to, but not including 18,000 feet MSL overlying: the 48 contiguous States including the waters within 12 miles from the coast of the 48 contiguous States; the District of Columbia; Alaska, including the waters within 12 miles from the coast of Alaska, and that airspace above FL 600; excluding the Alaska peninsula west of long. 160�'00"W., and the airspace below 1,500 feet above the surface of the earth unless specifically so designated.

(7) Offshore/Control Airspace Areas. Airspace areas beyond 12 NM from the coast of the United States, wherein ATC services are provided.

b. UNCONTROLLED AIRSPACE.

1. CLASS G AIRSPACE AREA. Airspace that has not been designated as Class A, Class B, Class C, Class D, or Class E airspace.

14-1-3. GOVERNING CRITERIA

Controlled airspace in terminal areas shall be designated, modified, or discontinued in accordance with the policy, procedures, and criteria contained herein.

14-1-4. FRACTIONAL MILES

Unless otherwise stated, all distances are nautical miles. When figuring the size of surface areas and Class E airspace or their extensions, any fractional part of a mile shall be converted to the next higher 0.1 mile increment.

EXAMPLE-
3.62 miles would be considered to be 3.7 miles.

14-1-5. AIRSPACE LEGAL DESCRIPTION

a. A text header shall be used and include the following information:

1. On line one:

(a) FAA routing symbol of the region.

(b) Two letter abbreviation of the state.

(c) Type of airspace.

2. On line two: Enter the name of the airport and, if different, preceded by the name of the city.

3. If applicable, on line three: Enter the geographic coordinates for the reference used to describe the airspace, that is, geographic position, airport reference point, NAVAID, etc.

4. If applicable, on subsequent lines: Enter any NAVAID or airport, including geographic coordinates, used in the legal description.

b. State vertical limits in the first sentence of the text.

c. Do not restate geographic coordinates used in the text header in the legal description text.

d. If applicable, the way to distinguish between the classes is to separate the description of basic radius from the extension description by using a semi-colon.

NOTE-
Do not include a vertical limit for any extension(s) that will become Class E airspace. See examples of airspace legal descriptions below.

EXAMPLES OF AIRSPACE LEGAL DESCRIPTIONS

ANE MA B BOSTON, MA
Logan International Airport (Primary Airport)
(lat. 42�'51"N., long. 70�'22"W.)

Boundaries.

Area A. That airspace extending upward from the surface to and including 7,000 feet MSL within an 8-mile radius of the Boston VORTAC.

Area B. That airspace extending upward from 2,000 feet MSL to and including 7,000 feet MSL within a 10.5-mile radius of the Boston VORTAC, excluding Area A.

Area C. That airspace extending upward from 3,000 feet MSL to and including 7,000 feet MSL within a 20-mile radius of the Boston VORTAC, excluding Areas A and B previously described and that airspace within and underlying Area D described hereinafter.

Area D. That airspace extending upward from 4,000 feet MSL to and including 7,000 feet MSL between the 15- and 20-mile radii of the Boston VORTAC extending from the Boston VORTAC 230' radial clockwise to the Boston VORTAC 005' radial.

ASW LA C SHREVEPORT REGIONAL AIRPORT, LA
Shreveport Regional Airport, LA
(lat. 32�'48"N., long. 93�'33"W.)
Barksdale AFB, LA
(lat. 32�'07"N., long. 93�'46"W.)

That airspace extending upward from the surface to and including 4,300 feet MSL within a 5-mile radius of the Shreveport Regional Airport, and that airspace extending upward from 1,600 feet MSL to and including 4,300 feet MSL within a 10-mile radius of the airport, excluding that airspace designated as the Barksdale AFB, LA, Class C airspace area east of the points where the 10-mile radius from Shreveport Regional Airport intersects the 10-mile radius from Barksdale AFB.

AEA VA D MANASSAS MUNICIPAL
Harry P. Davis Airport, Manassas, VA
(lat. 38�'17"N., long. 77�'56"W.)

That airspace extending upward from the surface to and including 2,000 feet MSL within a 4-mile radius of the Manassas Municipal/Harry P. Davis Airport; and that airspace extending upward from the surface within 2.6 miles either side of a bearing 025� from the airport extending from the 4-mile radius to 7.5 miles northeast of the airport and excluding that airspace within the Washington Tri-Area Class B area.