Chapter 20. Air Navigational Routes
Section 1. General
a. This chapter prescribes procedures and criteria for
the designation/establishment of Air Traffic Service (ATS)
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 must only be established in controlled
b. Where necessary, regions/service area offices must
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 must be forwarded to Airspace
Regulations and ATC Procedures Group for processing.
20-1-3. WHEN TO DESIGNATE AIR NAVIGATION ROUTES
routes should be designated to serve en route operations
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
2. Users will benefit from charted information
pertaining to navigational guidance, minimum en route
altitudes, and changeover points.
a. Service area office:
1. Must 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
2. Early coordination should be effected with Flight
Operations to ensure timeliness of input.
3. Must 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 FPT must process ATS routes requests in
accordance with appropriate FAA Orders.
designation of ATS routes must be avoided. All alpha-numeric
ATS route identifications must be assigned by Airspace
Regulations and ATC Procedures Group as follows:
a. Identify ATS routes based on L/MF NAVAIDs by color
names (e.g. Amber, Blue, Green, and Red) followed by a
1. Designate those routes extending east and west as
Green or Red.
2. Designate those extending north and south as Amber
ATS routes based on VOR NAVAIDs as follows:
lettering must be as follows:
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.
numbering must 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 must follow the guidelines detailed
in paragraph 20-1-5.b.1.(a)
d. Route segments must be listed from West to East for
even numbered ATS routes, or South to North for odd numbered
20-1-6. CHANGEOVER POINTS
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
must include the location in the proposal.
a. The base of an ATS route must 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
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
c. The criteria for surface area size shown in
FIG 17-2-1 and
FIG 17-2-2 must 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 must 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
action is initiated to raise the base of transitional
airspace associated with a route segment, care must be taken
to designate, in accordance with applicable criteria,
sufficient airspace to encompass IFR procedures prescribed
for airports which underlie the route. Additionally, care
must 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.