U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL AVIATION ADMINISTRATION

Chapter 20. Air Navigational Routes

Section 1. General

20-1-1. PURPOSE

a. This chapter prescribes procedures and criteria for the designation/establishment of Air Traffic Service (ATS) routes.

b. An ATS route is defined as a route designed for the management of air traffic operations or for the provision of air traffic services.

c. An ATS route may be a low/medium frequency (L/MF) route (which includes colored Federal airways); Very High Frequency Omnidirectional Range (VOR) Federal airways and jet routes; or an area navigation (RNAV) route.

d. Criteria and procedures for the development of an air navigation route(s) are contained in FAAO 8260.3, Terminal Instrument Procedures, and FAAO 8260.19, Flight Procedures and Airspace, unless otherwise specified.

20-1-2. CONTROLLED AIRSPACE

a. ATS routes shall only be established in controlled airspace.

b. Where necessary, regions/service area offices shall initiate the required action to designated controlled airspace of sufficient dimension to encompass the airspace to be protected and any associated course changes for ATS routes. This information shall be forwarded to Airspace and Rules for processing.

20-1-3. WHEN TO DESIGNATE AIR NAVIGATION ROUTES

ATS routes should be designated to serve en route operations when:

a. The route is predicated upon NAVAIDs that are suitable for inclusion in the system.

b. The benefits of the designation should outweigh any adverse effects to other airspace users, and:

1. The route is a normal extension of an existing airway; or

2. Users will benefit from charted information pertaining to navigational guidance, minimum en route altitudes, and changeover points.

20-1-4. RESPONSIBILITIES

a. Service area office:

1. Shall coordinate ATS routes with appropriate offices to determine if operational requirements and air traffic warrant a rulemaking action (e.g., ATC facilities, adjacent regional/service area offices, and regional Frequency Management Offices).

2. Early coordination should be effected with Flight Operations to ensure timeliness of input.

3. Shall maintain a program of systematic review of all ATS routes in their respective regions and initiate action to designate or adjust these routes as necessary.

b. Regional FPO shall process ATS routes requests in accordance with appropriate FAA Orders.

20-1-5. ROUTE IDENTIFICATION

Dual designation of ATS routes shall be avoided. All alpha-numeric ATS route identifications shall be assigned by Airspace and Rules as follows:

a. Identify ATS routes based on L/MF NAVAIDs by color names (e.g. Amber, Blue, Green, and Red) followed by a number designation.

1. Designate those routes extending east and west as Green or Red.

2. Designate those extending north and south as Amber or Blue.

b. Identify ATS routes based on VOR NAVAIDs as follows:

1. Route lettering shall be as follows:

(a) The letter "V" will prefix low altitude ATS routes below FL 180.

(b) The letter "J" will prefix high altitude ATS routes at FL 180 through FL 450.

2. Route numbering shall be as follows:

(a) Assign even numbers for those ATS routes extending east and west.

(b) Assign odd numbers for those ATS routes extending north and south.

c. Identify advanced RNAV ATS routes as follows:

1. The letter "T" will prefix low altitude RNAV ATS routes below FL 180, and the letter "Q" for RNAV routes FL 180 and above.

2. Route numbering shall follow the guidelines detailed in paragraph 20-1-5.b.1.(a) and b.2.

d. Route segments shall be listed from West to East for even numbered ATS routes, or South to North for odd numbered routes.

20-1-6. CHANGEOVER POINTS

When it is anticipated that the location of a changeover point will affect the lateral extent of an airway, en route domestic airspace area, offshore airspace area, or airspace to be protected for a jet route, the service area office shall include the location in the proposal.

20-1-7. BASE ALTITUDES

a. The base of an ATS route shall be at least 1,200 feet above the surface and at least 500 feet below the minimum en route altitude (MEA) except that route floors may be established no less than 300 feet below the MEA when:

1. The 500-foot buffer would result in the loss of a cardinal altitude; or

2. A definite operational advantage would exist.

b. The route floor should conform, as closely as possible to the floor of transitional airspace.

20-1-8. MINIMUM EN ROUTE ALTITUDES (MEA)

a. Procedures for establishing MEAs are set forth in FAAO 8260.3, TERPS, and FAAO 8260.19, Flight Procedures and Airspace.

b. When rounding off MEA to the nearest hundred feet results in vertical separation of not less than 451/251 feet between the floor of controlled airspace and the MEA, such separation is considered in compliance with the 500/300 feet specified.

c. The criteria for surface area size shown in FIG 17-2-1 and FIG 17-2-2 shall be used for determining airspace required for climb from the surface to 500/300 feet below the MEA/MOCA.

d. Use the criteria and procedures contained in appropriate FAA Orders for determining the airspace required for climb from one MEA to 500 feet below the higher MEA.

20-1-9. PROCEDURAL REQUIREMENTS

Procedural requirements may dictate designation of airspace lower than 500 feet below the MEA or MRA in certain en route radar vectoring areas or when necessary to accommodate climb or descent operations. Such airspace shall not be designated for the specific purpose of including a MOCA unless use of the MOCA is procedurally required.

20-1-10. ACTION TO RAISE BASE OF TRANSITIONAL AREAS

When action is initiated to raise the base of transitional airspace associated with a route segment, care shall be taken to designate, in accordance with applicable criteria, sufficient airspace to encompass IFR procedures prescribed for airports which underlie the route. Additionally, care shall be taken to ensure that controlled airspace, such as transition airspace or lower floor of control area, is provided for aircraft climbing from one minimum en route altitude to a higher one.