AIM

8/15/19

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15

En Route Procedures

the location and include duration of the anomaly if
necessary.

(i)

Any information relating to the safety of

flight.

2. When not in radar contact.

(a)

When leaving final approach fix inbound

on final approach (nonprecision approach) or when
leaving the outer marker or fix used in lieu of the outer
marker inbound on final approach (precision
approach).

(b)

A corrected estimate at anytime it

becomes apparent that an estimate as previously
submitted is in error in excess of 2 minutes. For
flights in the North Atlantic (NAT), a revised
estimate is required if the error is 3 minutes or more.

b.

Pilots encountering weather conditions which

have not been forecast, or hazardous conditions
which have been forecast, are expected to forward a
report of such weather to ATC.

REFERENCE

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AIM, Paragraph 7

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1

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20 , Pilot Weather Reports (PIREPs)

14 CFR Section 91.183(B) and (C).

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4. Airways and Route Systems

a.

Three fixed route systems are established for air

navigation purposes. They are the Federal airway
system (consisting of VOR and L/MF routes), the jet
route system, and the RNAV route system. To the
extent possible, these route systems are aligned in an
overlying manner to facilitate transition between
each.

1.

The VOR and L/MF (nondirectional radio

beacons) Airway System consists of airways
designated from 1,200 feet above the surface (or in
some instances higher) up to but not including 18,000
feet MSL. These airways are depicted on IFR Enroute
Low Altitude Charts.

NOTE

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The altitude limits of a victor airway should not be
exceeded except to effect transition within or between route
structures.

(a)

Except in Alaska, the VOR airways are:

predicated solely on VOR or VORTAC navigation
aids; depicted in black on aeronautical charts; and
identified by a “V” (Victor) followed by the airway
number (for example, V12).

NOTE

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Segments of VOR airways in Alaska are based on L/MF
navigation aids and charted in brown instead of black on
en route charts.

(1)

A segment of an airway which is

common to two or more routes carries the numbers of
all the airways which coincide for that segment.
When such is the case, pilots filing a flight plan need
to indicate only that airway number for the route filed.

NOTE

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A pilot who intends to make an airway flight, using VOR
facilities, will simply specify the appropriate “victor”
airway(s) in the flight plan. For example, if a flight is to be
made from Chicago to New Orleans at 8,000 feet, using
omniranges only, the route may be indicated as “departing
from Chicago

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Midway, cruising 8,000 feet via Victor 9 to

Moisant International.” If flight is to be conducted in part
by means of L/MF navigation aids and in part on
omniranges, specifications of the appropriate airways in
the flight plan will indicate which types of facilities will be
used along the described routes, and, for IFR flight, permit
ATC to issue a traffic clearance accordingly. A route may
also be described by specifying the station over which the
flight will pass, but in this case since many VORs and L/MF
aids have the same name, the pilot must be careful to
indicate which aid will be used at a particular location.
This will be indicated in the route of flight portion of the
flight plan by specifying the type of facility to be used after
the location name in the following manner: Newark L/MF,
Allentown VOR.

(2)

With respect to position reporting,

reporting points are designated for VOR Airway
Systems. Flights using Victor Airways will report
over these points unless advised otherwise by ATC.

(b)

The L/MF airways (colored airways) are

predicated solely on L/MF navigation aids and are
depicted in brown on aeronautical charts and are
identified by color name and number (e.g., Amber
One). Green and Red airways are plotted east and
west. Amber and Blue airways are plotted north and
south.

NOTE

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Except for G13 in North Carolina, the colored airway
system exists only in the state of Alaska. All other such
airways formerly so designated in the conterminous U.S.
have been rescinded.

(c)

The use of TSO

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C145 (as revised) or

TSO

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C146 (as revised) GPS/WAAS navigation

systems is allowed in Alaska as the only means of
navigation on published air traffic service (ATS)
routes, including those Victor, T

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Routes, and colored

airway segments designated with a second minimum