Section 1. General
- En Route Domestic Airspace Areas consist of Class E airspace that extends upward from a specified altitude to provide controlled airspace in those areas where there is a requirement to provide IFR en route ATC services but the Federal airway structure is inadequate. En Route Domestic Airspace Areas may be designated to serve en route operations when there is a requirement to provide ATC service but the desired routing does not qualify for airway designation. Consideration may also be given to designation of En Route Domestic Airspace Areas when:
- The NAVAIDs are not suitable for inclusion in the airway system, but are approved under Part 171, are placed in continuous operation, and are available for public use; or
- Navigation is by means of radar vectoring. En route Domestic Airspace Areas are listed in FAA Order JO 7400.11, Airspace Designations and Reporting Points.
- En Route Domestic Airspace Areas are designated under 14 CFR § 71.71 and are listed in FAA Order JO 7400.11, Airspace Designations and Reporting Points.
- Offshore/Control Airspace Areas are locations designated in international airspace (between the U.S. 12-mile territorial limit and the CTA/FIR boundary, and within areas of domestic radio navigational signal or ATC radar coverage) wherein domestic ATC procedures may be used for separation purposes.
- These areas provide controlled airspace where there is a requirement to provide IFR en route ATC services, and to permit the application of domestic ATC procedures in that airspace.
- Class A Offshore/Control Airspace Areas are identified as “High" (for example, Atlantic High; Control 1154H). Class E areas are identified as “Low" (for example, Gulf of Mexico Low, Control 1141L).
- Since there is no standard established for offshore routes NAVAID spacing, such spacing should be determined on a regional, site-by-site basis.
- In determining which configuration to use, consider user requirements, NAVAID quality and dependability, radar vectoring capabilities, transition to/from offshore airspace areas, requirements of other users for adjacent airspace, and possible future requirements for controlled airspace.
- Offshore/Control areas that require use of one NAVAID for an extended distance should be based on L/MF facilities so that lower MEAs can be established.
Care should be exercised in relocating NAVAIDs on which offshore airspace areas are based so that the desired offshore airspace configuration can be retained.
- Where Offshore/Control Class E airspace is extended to the domestic/oceanic boundary, the diverging lines must terminate at their intersection with the domestic/oceanic boundary.
Offshore control airspace areas are designated in Sections 71.33 and 7l.71. These areas are listed in FAA Order JO 7400.11, Airspace Designations and Reporting Points.
Offshore airspace area rulemaking actions are processed by Rules and Regulations Group. Regions/service area offices may process those domestic cases that are ancillary to a terminal airspace action with approval of Rules and Regulations Group.