Standard Radio Phraseology
ICAO standard phraseology is the unified vocabulary of radiotelephony. The phrases have defined meaning, are short, and are understood worldwide.
Source: ICAO Doc 9432 Manual of Radiotelephony (5th ed., 2022), particularly Chapter 2 + Annex A.
Most important phrases
| Phrase | Meaning |
|---|---|
| Affirm | "Yes" / "Confirmed" / "Correct" |
| Negative | "No" / "Permission for proposed action is NOT granted" |
| Approved | "Permission for proposed action is granted" |
| Request | used to introduce a request ("Request taxi", "Request lower altitude") |
| Roger | "I have received all of your last transmission" — confirms complete receipt of previous transmission. Not "yes", not "understood", not "will comply". |
| Wilco | "Will Comply" — "I understand your message and will act accordingly" — understood and will be obeyed |
| Standby | "Wait" / "Stay on the line" |
| Read Back | "Repeat the message" — used when ATC or another party asks the pilot to repeat |
| Say Again | "Repeat the message" |
| Correction | "Correction — the following is the correct information" / "An error has been made in this transmission. The correct version is…" |
| Confirm | used when a message was readable but ambiguous |
| Monitor | "Monitor the frequency/channel" — listen but do not call |
| Disregard | "Ignore the last statement" |
| Out | "End of this transmission" |
| Over | "End of my transmission — your reply" |
| Unable | "Cannot comply" |
| Acknowledge | "Confirm receipt" |
| Cleared | "Cleared" (official clearance phrase) |
| Cancel | "Cancel" (e.g. a clearance) |
| Maintain | "Maintain" (altitude, heading, speed) |
| Climb / descend | "Climb / descend" |
| Hold / holding | "Hold" (position) |
| Hold short | "Hold short of [e.g. runway]" |
| Position and hold / line up and wait | "Line up and wait" on runway |
| Taxi | "Taxi" |
| Final | "Final approach" |
| Going around | "Going around" |
| Caution Wake Turbulence | issued by ATC when a lighter aircraft follows a heavier — pilot warned of possible wake turbulence (see Subject 070) |
| Mayday / Pan Pan | distress / urgency |
"Roger" — important clarification
"Roger" means ONLY: "I have received all of your last transmission".
- NOT "Understood" (that would be "I understand" or read-back).
- NOT "Will comply" (that is Wilco).
- NOT "Yes" (that is Affirm).
If ATC says: "DEMRA, climb to flight level 100", the correct pilot reply is:
- ✅ "Climb to flight level 100, DEMRA" (read-back demonstrates understanding AND readiness)
- ❌ "Roger" alone — only shows receipt, not action or understanding.
"Affirm" vs "Yes" / "Negative" vs "No"
- Affirm is standard. Yes is often accepted in local traffic, but Affirm is unambiguous.
- Negative is standard. No should be avoided — can be confused with "Know".
"Say again" — variants
- Say again — repeat the whole message.
- Say again all after [X] — repeat from the word/item X onward.
- Say again all before [X] — repeat up to the item X.
- Say again [item] — repeat only the named information.
Correction
Correction (used by pilot or ATC):
- "DEMRA climb to flight level 90 — correction — flight level 100."
"Disregard"
ATC uses "disregard" when an instruction is rescinded:
- "DEMRA, turn left heading 270 — disregard the previous instruction."
Pilot then ignores the old instruction and waits for a new one.
Vital phrases
| Phrase | Meaning | When |
|---|---|---|
| Cleared for take-off | Take-off cleared | Tower clearance |
| Hold position | Stop | on traffic conflict |
| Go around | Go-around ordered | usually by tower |
| Traffic in sight | Other traffic seen | after VFR sight call |
| Negative contact | Traffic not seen | when other traffic not visible |
| Looking | Still searching | before confirming |
Altitude / level phrases
- Climb to [altitude/FL] = climb to.
- Descend to [altitude/FL] = descend to.
- Maintain [altitude] = maintain.
- Report leaving [altitude] = report when leaving this altitude.
- Report reaching [altitude] = report on reaching this altitude.
Speed phrases
- Slow down.
- Maintain present speed.
- Adjust speed to [X knots].
Frequency change
- Contact [station] on [frequency] = switch to new frequency and call.
- Monitor [frequency] = listen only, no call.
- Squawk [code] = set transponder code.
- Ident = press IDENT button on transponder.
Read-Back — Mandatory List
ICAO Annex 10 Vol II §5.2.1.7 and Doc 9432 Chapter 3 define items that must be read back verbatim:
Items that ALWAYS require read-back
| Item | Example read-back |
|---|---|
| Runway in use (runway assignment) | "Runway 26, DEMRA" |
| QNH / altimeter setting | "QNH 1015, DEMRA" |
| SSR code (squawk) | "Squawk 4321, DEMRA" |
| SSR mode (e.g. "Squawk Alpha", "Mode Charlie") | "Squawk Mode Charlie, DEMRA" |
| Clearances | verbatim, e.g. "Cleared for take-off runway 26, DEMRA" |
| Heading instructions | "Heading 270, DEMRA" |
| Altitude instructions | "Climb 5000 ft, DEMRA" |
| Speed instructions | "Maintain 90 knots, DEMRA" |
| Frequency change | "121.275, DEMRA" |
| Atmospheric pressure values (QFE, QNE) | "QFE 1010, DEMRA" |
Items NOT to be read back
| Item | Acknowledgement |
|---|---|
| Wind information | NOT read back — just note |
| Traffic information | NOT read back — respond with "Traffic in sight" / "Negative contact" / "Looking" |
| "Entering airspace D" (advisory) | Acknowledge with "Roger" — no full read-back |
| "Next report PAH" (reporting point advisory) | Acknowledge with "Wilco" — understood and will comply |
Read-back examples
Complex take-off clearance
ATC: "DZF after lift-off, climb straight-ahead until 2500 feet before turning right heading 220 degrees, wind 090 degrees, 5 knots, runway 12, cleared for take-off"
Pilot read-back (shorter form, key items): "DZF after lift-off, climb straight ahead 2500 feet, then turn right heading 220, runway 12, cleared for take-off"
→ Wind is NOT read back, as it is not a binding instruction (only information).
Frequency + squawk
ATC: "Squawk 4321, Call Bremen Radar on 131.325" Pilot: "Squawk 4321, 131.325" — both items.
Frequency alone
ATC: "Call Hamburg Tower on 121.275" Pilot: "121.275" — pronounce: "One Two One Decimal Two Seven Five".
Take-off clearance
ATC: "DEMRA, runway 24, cleared for take-off" Pilot: "DEMRA, runway 24, cleared for take-off"
- Order: callsign + runway + clearance — exact repetition.
Common errors
- "Roger" for everything — should be replaced by read-back for critical items.
- "Yes" / "No" instead of "Affirm" / "Negative".
- "OK" / "thanks" are not standard phraseology.
- Confusion "hold" (wait) vs "hold short" (wait before runway).
- Wind read-back attempted — superfluous.
- Traffic-info read-back instead of "Traffic in sight" — wrong.
Training tip
Practise speaking in standard phraseology even when local language is allowed — the standard phrases are intelligible worldwide, even in language confusion.