4/20/23
AIM
obvious reply and there is no possibility for misunderstandings.
You should acknowledge all callups or
clearances
unless the controller or FSS specialist advises otherwise. There are some occasions when controllers
must issue time-critical instructions to other aircraft, and they may be in a position to observe your response,
either visually or on radar. If the situation demands your response, take appropriate action or immediately advise
the facility of any problem. Acknowledge with your aircraft identification, either at the beginning or at the end
of your transmission, and one of the words “Wilco,” “Roger,” “Affirmative,” “Negative,” or other appropriate
remarks; e.g., “PIPER TWO ONE FOUR LIMA, ROGER.” If you have been receiving services; e.g., VFR traffic
advisories and you are leaving the area or changing frequencies, advise the ATC facility and terminate contact.
d. Acknowledgement of Frequency Changes.
1.
When advised by ATC to change frequencies, acknowledge the instruction. If you select the new
frequency without an acknowledgement, the controller’s workload is increased because there is no way of
knowing whether you received the instruction or have had radio communications failure.
2.
At times, a controller/specialist may be working a sector with multiple frequency assignments. In order
to eliminate unnecessary verbiage and to free the controller/specialist for higher priority transmissions, the
controller/specialist may request the pilot “(Identification), change to my frequency 134.5.” This phrase should
alert the pilot that the controller/specialist is only changing frequencies, not controller/specialist, and that initial
callup phraseology may be abbreviated.
EXAMPLE
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“United Two Twenty
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Two on one three four point five” or “one three four point five, United Two Twenty
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Two.”
e. Compliance with Frequency Changes.
When instructed by ATC to change frequencies, select the new frequency as soon as possible unless instructed
to make the change at a specific time, fix, or altitude. A delay in making the change could result in an untimely
receipt of important information. If you are instructed to make the frequency change at a specific time, fix, or
altitude, monitor the frequency you are on until reaching the specified time, fix, or altitudes unless instructed
otherwise by ATC.
REFERENCE
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AIM, Para 5
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4. Aircraft Call Signs
a. Precautions in the Use of Call Signs.
1.
Improper use of call signs can result in pilots executing a clearance intended for another aircraft. Call
signs should
never be abbreviated on an initial contact or at any time when other aircraft call signs have similar
numbers/sounds or identical letters/number;
e.g., Cessna 6132F, Cessna 1622F, Baron 123F, Cherokee 7732F,
etc.
EXAMPLE
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Assume that a controller issues an approach clearance to an aircraft at the bottom of a holding stack and an aircraft with
a similar call sign (at the top of the stack) acknowledges the clearance with the last two or three numbers of the aircraft’s
call sign. If the aircraft at the bottom of the stack did not hear the clearance and intervene, flight safety would be affected,
and there would be no reason for either the controller or pilot to suspect that anything is wrong. This kind of “human factors”
error can strike swiftly and is extremely difficult to rectify.
2.
Pilots, therefore, must be certain that aircraft identification is complete and clearly identified before
taking action on an ATC clearance. ATC specialists will not abbreviate call signs of air carrier or other civil
aircraft having authorized call signs. ATC specialists may initiate abbreviated call signs of other aircraft by using
the
prefix and the last three digits/letters
of the aircraft identification after communications are established. The
pilot may use the abbreviated call sign in subsequent contacts with the ATC specialist. When aware of
similar/identical call signs, ATC specialists will take action to minimize errors by emphasizing certain
numbers/letters, by repeating the entire call sign, by repeating the prefix, or by asking pilots to use a different
call sign temporarily. Pilots should use the phrase “VERIFY CLEARANCE FOR (your complete call sign)” if
doubt exists concerning proper identity.
Radio Communications Phraseology
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