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. CONTROLLED AIRSPACE

Controlled airspace is airspace of defined dimensions within which ATC service is provided to IFR and VFR ­flights in accordance with the airspace classification. Within controlled airspace, all aircraft operators are subject ­to certain qualification, operating, and aircraft equipage requirements (see Title 14 CFR part 91). Controlled ­airspace in the United States is designated in 14 CFR part 71 as follows:

  1. CLASS A AIRSPACE. That airspace from 18,000 feet MSL to 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.
  2. CLASS B AIRSPACE. Generally, that airspace from the surface to 10,000 feet 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."
  3. CLASS C AIRSPACE. 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.
  4. CLASS D AIRSPACE. 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, ­except as noted in FAA Orders JO 7110.65, Air Traffic Control; and JO 7210.3, Facility Operation and ­Administration.
  5. CLASS E AIRSPACE. Class E airspace is controlled airspace that is designated to serve a variety of ­terminal or en route purposes as described in this paragraph. Class E airspace consists of:
    1. The airspace extending upward from 14,500 feet MSL to, but not including, 18,000 feet MSL overlying ­the 48 contiguous States, the District of Columbia and Alaska, including the waters within 12 NM from the coast ­of the 48 contiguous States and Alaska; excluding the Alaska Peninsula west of longitude 160º00'00''W., and ­the airspace below 1,500 feet above the surface of the earth. (The 1,500 feet above the surface exclusion from ­Class E airspace above 14,500 feet MSL would apply in mountainous terrain areas.)
    2. The airspace above FL 600.
    3. Surface area designation for an airport where a control tower is not in operation and for non-towered ­airports. Class E surface areas extend upward from the surface to a designated altitude, or to the adjacent or ­overlying controlled airspace. When designated, the airspace will be configured to contain all instrument ­procedures.
    4. Extension to a surface area. Airspace designated as extensions to Class C, Class D, and Class E surface ­areas. Class E airspace extensions begin at the surface and extend upward to the overlying controlled airspace. ­The extensions provide controlled airspace to contain standard instrument approach procedures without ­imposing communication requirements on pilots operating in visual meteorological conditions.
    5. Airspace used for transition. Airspace extending upward from either 700 feet or 1,200 feet AGL to the ­overlying controlled airspace designated for transitioning aircraft to/from the terminal or en route environments.
    6. Federal airways and low-altitude RNAV routes. Federal airways and low-altitude RNAV routes are ­Class E airspace and unless otherwise specified, extend upward from 1,200 feet AGL to, but not including, ­18,000 feet MSL.
    7. Offshore/Control Airspace Areas. Airspace designated in international airspace, extending outward ­from 12 NM from the coast of the United States to the CTA/FIR boundary, in accordance with the criteria in 14 ­CFR part 71, within which the United States applies domestic ATC procedures.
    8. En Route Domestic Airspace. Airspace extending upward from a specified altitude to, but not including, ­18,000 feet MSL designated for providing IFR en route ATC services where the Federal airway system is ­inadequate.

14-1-3. UNCONTROLLED AIRSPACE

Airspace that is not designated in 14 CFR part 71 as Class A, Class B, Class C, Class D, or Class E controlled ­airspace is Class G (uncontrolled) airspace.

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 must be converted to the next higher 0.1-mile increment.

14-1-5. AIRSPACE LEGAL DESCRIPTION

  1. A text header must be used and include the following information:
    1. On line one:
      1. FAA routing symbol of the region.
      2. Two-letter abbreviation of the state.
      3. Type of airspace.
      4. Location (City, State)
    2. On line two: Enter the name of the airport (Name, State) for which the airspace is designated.
    3. On line three: Enter the geographic coordinates for the airport for which the airspace is designated.
    4. If applicable, on subsequent lines: Enter the name of any NAVAID or airport, point of origin, or other ­reference used in the legal description. Include the NAVAID or airport geographic coordinates on the line ­following the name.
  2. State vertical limits in the first sentence of the text.
  3. Do not restate geographic coordinates used in the text header in the legal description text.
  4. If applicable, use a semicolon to separate the description of geographically separate sub-areas.

14-1-6. EXAMPLES OF TERMINAL AIRSPACE LEGAL DESCRIPTIONS

  1. EXAMPLE 1-
    ANE MA B BOSTON, MA
    Logan International Airport, MA (Primary Airport)
    (lat. 42_21'51"N., long. 70_59'22"W.)
    Boston VORTAC
    (lat. 42_21'27"N., long. 70_59'22"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.

  2. EXAMPLE 2-
    ANM MT C Billings, MT
    Billings Logan International Airport, MT
    (lat. 45_48'30"N., long. 108_32'38"W.)

    That airspace extending upward from the surface to and including 7,700 feet MSL within a 5-mile radius of the ­Billings Logan International Airport; and that airspace extending upward from 4,900 feet MSL to and including ­7,700 feet MSL within a 10-mile radius of the airport
  3. EXAMPLE 3-
    AGL MN D Duluth, MN
    Duluth International Airport, MN
    (lat. 46_50'32"N., long. 92_11'38"W.)

    That airspace extending upward from the surface to and including 3,900 feet MSL within a 4.9-mile radius of ­Duluth International Airport.
  4. EXAMPLE 4-
    AEA VA E2 Danville, VA
    Danville Regional Airport, VA
    (lat. 36_34'22''N., long. 79_20'10''W.)

    That airspace extending upward from the surface within a 5-mile radius of Danville Regional Airport and within ­2.4-miles each side of a 208_ bearing from the airport, extending from the 5-mile radius to 7 miles southwest ­of the airport, and within 2.4-miles each side of a 016_ bearing from the airport, extending from the 5-mile ­radius to 7 miles northeast of the airport.