3/21/24 

AIM 

Additionally available at U.S. 

http://www.fly.faa.gov/Products/Coded_Departure_Routes/NFDC_Preferred_Routes_Database/nfdc_preferred_routes_database.html

. 

6. 

ATC may issue a SID or a STAR, as appropriate. 

REFERENCE

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AIM, Para 5

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2

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9, Instrument Departure Procedures (DP) 

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Obstacle Departure Procedures (ODP) and Standard Instrument Departures (SID), and 

Diverse Vector Areas (DVA). 

AIM, Para 5

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4

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1, Standard Terminal Arrival (STAR) Procedures. 

NOTE

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Pilots not desiring an RNAV SID or RNAV STAR should enter in Item #18, PBN code: NAV/RNV A0 and/or D0. 

c.  Direct Flights 

1. 

All or any portions of the route which will not be flown on the radials or courses of established airways 

or routes, such as direct route flights, must be defined by indicating the radio fixes over which the flight will pass. 

Fixes selected to define the route must be those over which the position of the aircraft can be accurately 

determined. Such fixes automatically become compulsory reporting points for the flight, unless advised 

otherwise by ATC. Only those navigational aids established for use in a particular structure; i.e., in the low or 

high structures, may be used to define the en route phase of a direct flight within that altitude structure. 

2. 

The azimuth feature of VOR aids and the azimuth and distance (DME) features of VORTAC and TACAN 

aids are assigned certain frequency protected areas of airspace which are intended for application to established 

airway and route use, and to provide guidance for planning flights outside of established airways or routes. These 

areas of airspace are expressed in terms of cylindrical service volumes of specified dimensions called “class 

limits” or “categories.” 

REFERENCE

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AIM, Para 1

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1

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8, Navigational Aid (NAVAID) Service Volumes. 

3. 

An operational service volume has been established for each class in which adequate signal coverage and 

frequency protection can be assured. To facilitate use of VOR, VORTAC, or TACAN aids, consistent with their 

operational service volume limits, pilot use of such aids for defining a direct route of flight in controlled airspace 

should not exceed the following: 

(a) 

Operations above FL 450 

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 Use aids not more than 200 NM apart. These aids are depicted on en route 

high altitude charts. 

(b) 

Operation off established routes from 18,000 feet MSL to FL 450 

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 Use aids not more than 260 NM 

apart. These aids are depicted on en route high altitude charts. 

(c) 

Operation off established airways below 18,000 feet MSL 

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 Use aids not more than 80 NM apart. 

These aids are depicted on en route low altitude charts. 

(d) 

Operation off established airways between 14,500 feet MSL and 17,999 feet MSL in the 

conterminous U.S. 

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 (H) facilities not more than 200 NM apart may be used. 

4. 

Increasing use of self

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contained airborne navigational systems which do not rely on the 

VOR/VORTAC/TACAN system has resulted in pilot requests for direct routes which exceed NAVAID service 

volume limits. 

5. 

At times, ATC will initiate a direct route in a surveillance environment which exceeds NAVAID service 

volume limits. Pilots must adhere to the altitude specified in the clearance. 

6. 

Appropriate airway or jet route numbers may also be included to describe portions of the route to be 

flown. 

EXAMPLE

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MDW V262 BDF V10 BRL STJ SLN GCK Spelled out: from Chicago Midway Airport via Victor 262 to Bradford, Victor 10 

to Burlington, Iowa, direct St. Joseph, Missouri, direct Salina, Kansas, direct Garden City, Kansas. 

NOTE

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When route of flight is described by radio fixes, the pilot will be expected to fly a direct course between the points named. 

Preflight 

5

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1

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13