ATC Phraseology
Standard radiotelephony phraseology for pilots — aligned with ICAO Annex 10 and UK CAA CAP 413.
Last reviewed: March 2026
Standard phraseology exists to reduce misunderstandings in radio communications. Pilots must read back specific elements of clearances to confirm receipt. When standard phraseology does not cover a situation, plain language may be used — but always be clear, concise, and unambiguous.
Read-Back Requirements
The following items MUST be read back in full when received from ATC: ATC route clearances, clearances and instructions to enter, land on, take off from, hold short of, cross, or taxi on any runway, runway-in-use information, altimeter settings, SSR codes (squawk), level instructions, heading and speed instructions, transition levels.
General Calling Procedure
Standard call structure: WHO YOU ARE CALLING + WHO YOU ARE + YOUR POSITION/LEVEL + WHAT YOU WANT. Always establish two-way communications before transmitting a full message on first contact with a new unit.
Pre-Flight / Clearance Delivery
| Situation | Pilot Says | ATC Responds |
|---|---|---|
| Request IFR clearance | "[callsign], request clearance to [destination], [aircraft type], [departure time]" | "[callsign], cleared to [dest], [route], climb [level], squawk [code]" |
| Read back clearance | "[Read back full clearance], [callsign]" | "Readback correct" or "Negative, [correction]" |
| Request start-up | "[callsign], request start-up" | "[callsign] start-up approved" or "not yet available, expect [time]" |
| Request ATIS | "[callsign], request ATIS information" | "ATIS information [letter], [time], [conditions summary]" |
| Confirm ATIS received | "[callsign], information [letter]" | "[callsign] roger" |
Ground Movement (Taxi)
| Situation | Example Exchange |
|---|---|
| Request taxi | "Speedbird 123, request taxi, information Charlie." ATC: "Speedbird 123, taxi to holding point Runway 27L via Alpha, Bravo." |
| Read-back (mandatory) | "Taxi holding point Runway 27L via Alpha, Bravo, Speedbird 123." Runway and hold-short instructions must always be read back. |
| Hold position | ATC: "Speedbird 123, hold position." Pilot: "Holding, Speedbird 123." |
| Crossing runway | ATC: "Speedbird 123, cross Runway 09." Pilot: "Cross Runway 09, Speedbird 123." |
| Line-up instruction | ATC: "Speedbird 123, line up Runway 27L." Pilot: "Lining up Runway 27L, Speedbird 123." |
Take-Off
| Situation | ATC | Pilot |
|---|---|---|
| Conditional line-up clearance | "Speedbird 123, behind the landing Boeing 737, line up Runway 27L" | "Behind the Boeing 737, lining up Runway 27L, Speedbird 123" |
| Take-off clearance | "Speedbird 123, wind 270 degrees 12 knots, cleared take-off Runway 27L" | "Cleared take-off Runway 27L, Speedbird 123" |
| Take-off abandoned | "Speedbird 123, stop immediately, stop immediately" | "Stopping, Speedbird 123" — declare MAYDAY and squawk 7700 if emergency |
Departure / En-Route
| Situation | Example Call |
|---|---|
| Initial contact after take-off | "[callsign], airborne [time], passing [level], climbing [cleared level]" |
| Level report | "[callsign], maintaining Flight Level [XXX]" |
| Requesting higher level | "[callsign], request Flight Level [XXX]" |
| Reporting position | "[callsign], [position], [level], estimating [next position] at [time]" |
| Requesting direct routing | "[callsign], request direct [waypoint]" |
| Frequency change | ATC: "Contact [unit] [frequency], [callsign]" Pilot: "Contact [unit] [frequency], [callsign]" — read-back required |
Approach & Landing
| Situation | ATC | Pilot |
|---|---|---|
| Descent for approach | "[callsign] descend to [level], expect ILS Runway 27L" | "Descend [level], expect ILS Runway 27L, [callsign]" |
| Speed control | "[callsign] reduce speed to 180 knots" | "Reducing to 180 knots, [callsign]" |
| ILS approach clearance | "[callsign] cleared ILS approach Runway 27L" | "Cleared ILS approach Runway 27L, [callsign]" |
| Landing clearance | "[callsign] wind 270/10, cleared to land Runway 27L" | "Cleared to land Runway 27L, [callsign]" |
| Go-around | "[callsign] go around" | "Going around, [callsign]" — execute published missed approach immediately |
Common Standard Phrases
| Phrase | Meaning |
|---|---|
Roger | I have received all of your last transmission |
Wilco | I understand and will comply (implies "Roger" — do not say "Roger Wilco") |
Affirm | Yes (never use "affirmative" or "yes") |
Negative | No / that is not correct |
Say again | Repeat your last transmission (never use "repeat" — reserved for artillery) |
Stand by | Wait — I will call you (no reply required; not a clearance to act) |
Confirm | Have I correctly received the following… / Is that correct? |
Correct | That is correct |
Approved | Permission granted for the proposed action |
Unable | Cannot comply with the instruction or request |
Words twice | Communication difficult — transmit each phrase twice |
Check | Examine a system or procedure (no reply expected) |
Transponder / Squawk Instructions
| Instruction from ATC | Pilot Action & Read-Back |
|---|---|
| "Squawk [code]" | Set transponder to given 4-digit code. Read back: "Squawk [code], [callsign]" |
| "Squawk IDENT" | Press the IDENT button once. Read back: "Ident, [callsign]" |
| "Squawk standby" | Select transponder standby mode (no reply is transmitted) |
| "Squawk Charlie" | Select Mode C — enable altitude reporting |
| "Stop squawk Charlie" | Turn off Mode C altitude reporting |
Distress and Urgency
MAYDAY MAYDAY MAYDAY — Distress call. Transmit the word three times before the message. Indicates grave and imminent danger requiring immediate assistance. Squawk 7700.
PAN PAN PAN PAN PAN PAN — Urgency call. Transmit three times before the message. Indicates an urgent situation not requiring immediate assistance but needing priority handling.
See Emergency Procedures for full guidance on distress calls, emergency squawk codes, and lost communications procedures.
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