NOTE-
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-
AIM, Para 1-1-8, 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 - 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 - 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 - 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. - (H) facilities not more than 200 NM apart may be used.
4. Increasing use of self-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-
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-
When route of flight is described by radio fixes, the pilot will be expected to fly a direct course between the points named.

7. Pilots are reminded that they are responsible for adhering to obstruction clearance requirements on those
segments of direct routes that are outside of controlled airspace and ATC surveillance capability. The MEAs and
other altitudes shown on IFR en route charts pertain to those route segments within controlled airspace, and those
altitudes may not meet obstruction clearance criteria when operating off those routes.
NOTE-
Refer to 14 CFR 91.177 for pilot responsibility when flying random point to point routes.

Preflight

5-1-13