Aeronautical Information Manual (AIM), page 325

Index   324 -- Page 325 -- 326

The exchange of information between an aircraft and an
ARTCC through an FSS is quicker than relay via company
radio because the FSS has direct interphone lines to the
responsible ARTCC sector. Accordingly, when circum-
stances dictate a choice between the two, during an
ARTCC frequency outage, relay via FSS radio is

5-3-2. Position Reporting

The safety and effectiveness of traffic control
depends to a large extent on accurate position
reporting. In order to provide the proper separation
and expedite aircraft movements, ATC must be able
to make accurate estimates of the progress of every
aircraft operating on an IFR flight plan.
a. Position Identification.

1. When a position report is to be made passing
a VOR radio facility, the time reported should be the

time at which the first complete reversal of the

"to/from" indicator is accomplished.

2. When a position report is made passing a
facility by means of an airborne ADF, the time
reported should be the time at which the indicator
makes a complete reversal.
3. When an aural or a light panel indication is
used to determine the time passing a reporting point,
such as a fan marker, Z marker, cone of silence or
intersection of range courses, the time should be
noted when the signal is first received and again when
it ceases. The mean of these two times should then be
taken as the actual time over the fix.

4. If a position is given with respect to distance
and direction from a reporting point, the distance and

direction should be computed as accurately as
5. Except for terminal area transition purposes,

position reports or navigation with reference to aids

not established for use in the structure in which flight
is being conducted will not normally be required by

b. Position Reporting Points. CFRs require

pilots to maintain a listening watch on the appropriate
frequency and, unless operating under the provisions
of subparagraph c, to furnish position reports passing
certain reporting points. Reporting points are
indicated by symbols on en route charts. The

designated compulsory reporting point symbol is a
solid triangle and the "on request" reporting

point symbol is the open triangle . Reports
passing an "on request" reporting point are only
necessary when requested by ATC.
c. Position Reporting Requirements.

1. Flights Along Airways or Routes. A
position report is required by all flights regardless of

altitude, including those operating in accordance with
an ATC clearance specifying "VFR-on-top," over
each designated compulsory reporting point along the
route being flown.
2. Flights Along a Direct Route. Regardless
of the altitude or flight level being flown, including
flights operating in accordance with an ATC
clearance specifying "VFR-on-top," pilots must
report over each reporting point used in the flight plan
to define the route of flight.

3. Flights in a Radar Environment. When

informed by ATC that their aircraft are in "Radar

Contact," pilots should discontinue position reports
over designated reporting points. They should
resume normal position reporting when ATC advises
4. Flights in an Oceanic (Non-radar) Envir-
onment. Pilots must report over each point used in
the flight plan to define the route of flight, even if the
point is depicted on aeronautical charts as an "on
request" (non-compulsory) reporting point. For
aircraft providing automatic position reporting via an
Automatic Dependent Surveillance-Contract
(ADS-C) logon, pilots should discontinue voice
position reports.

ATC will inform pilots that they are in "radar contact":
(a) when their aircraft is initially identified in the ATC
system; and
(b) when radar identification is reestablished after

radar service has been terminated or radar contact lost.
Subsequent to being advised that the controller has
established radar contact, this fact will not be repeated to
the pilot when handed off to another controller. At times,
the aircraft identity will be confirmed by the receiving

controller; however, this should not be construed to mean
that radar contact has been lost. The identity of
transponder equipped aircraft will be confirmed by asking
the pilot to "ident," "squawk standby," or to change codes.
Aircraft without transponders will be advised of their
position to confirm identity. In this case, the pilot is

En Route Procedures 5-3-3

Page 325 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures

Index   324 -- Page 325 -- 326