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Overview
Air Route Traffic Control Centers (ARTCCs), known to pilots as "Centers," are
capable of direct communications with IFR air traffic on certain frequencies.
Maximum communications coverage is possible through the use of Remote Center Air/Ground
(RCAG) sites comprised of both VHF and UHF transmitters and receivers. These sites are
located throughout the US. Although they may be several hundred miles away from the ARTCC,
they are remoted to the various ARTCCs by land lines or microwave links.
Since IFR operations are expedited through the use of direct communications, pilots are
requested to use these frequencies strictly for communications pertinent to the control of
IFR aircraft. Flight plan filing, en route weather, weather forecasts and similar data
should be requested through FSSs, company radio, or appropriate military facilities
capable of performing these services.
ATC Frequency Change Procedures
An ARTCC is divided into sectors. Each sector is handled by one controller or, in some cases,
a team of controllers and has its own discrete sector frequency. As a flight progresses from
one sector to another, ATC will ask the pilot to change to the appropriate sector frequency.
ATC will use the following phraseology to instruct the pilot to make a frequency change:
(Aircraft Identification), contact (facility name or location name and terminal
function) on (frequency) at (time, fix or altitude).
When advised by ATC to change frequencies, first acknowledge the instruction.
If you select the new frequency without an acknowledgment, the controller's work load is
increased because he or she has no way of knowing whether you received the instruction or
have had radio communications failure.
If you are instructed to make the frequency change at a specific time, fix, or altitude,
continue to monitor the frequency you are on until reaching the point specified for the
frequency change. ATC will omit frequency change restrictions whenever pilot compliance is
expected upon receipt. If there are no frequency change restrictions, therefore, you should
select the new frequency as soon as possible after acknowledging the
instruction. A delay in making the change could cause you to miss important information.
When you make the frequency change, change, you should first listen on the new
frequency. If you hear someone else talking, attempting to transmit will "step on"
(jam) someone else's attempt to transmit, causing a need to repeat the call and wasting time
for everyone. Make sure the frequency is clear before you attempt to transmit.
Your initial call after being handed off to a new controller can be very brief. Examples:
With VFR Flight Following:Salt Lake Center, Skylane 54321, four
thousand, five hundred, VFR.
On IFR Flight Plan:Jacksonville Center, Skylane 54321, five
thousand, assigned heading two three zero.
Position Reports
To make an IFR position report, use the following phraseology:
(Name) CENTER,
(aircraft identification), (position), (time), (time to next fix), (time to following fix).
For example:
(Name) Center, (aircraft identification), estimating (reporting point and time) at (altitude
or flight level) climbing (or descending) to (altitude or flight level).
Note that exact altitude or flight level means to the nearest 100 foot increment. Exact
altitude or flight level reports on initial contact provide ATC with information
required prior to using MODE C altitude information for separation purposes. At times,
controllers will ask pilots to verify that altitude. The phraseology used will be:
"Verify at (altitude)."
In climbing or descending situations, controllers may ask pilots to "Verify
assigned altitude as (altitude)." Pilots should confirm that they are at
the altitude stated by the controller or that the assigned altitude is correct as stated.
If this is not the case, they should inform the controller of the actual altitude being
maintained or the different assigned altitude. Important: Pilots should
not take action to change actual altitude or different assigned altitude to the
altitude stated in the controller's verification request, unless the controller specifically
authorizes a change.
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