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VHF radiocommunications

Radiotelephony phrasing
— aviation English

Rev. 11 — page content was last changed 18 August 2010
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It is most important that the intent of each aviation radiotelephony transmission is clearly stated — and readily understood and remembered by recipients. Putting the necessary words together before transmitting, keeping it brief, using the standard terminology and phrasing — aviation English — and always using your complete and correct call sign are the keys to communicating useful operational information.

Most of the material in this page is extracted from the Aeronautical Information Publication Australia book [AIP], published by the Aeronautical Information Service of Airservices Australia. The relevant section in the AIP is noted in the text headings. The full and up-to-date text is available online at the Airservices Australia website; to access AIP please first read this paragraph in the 'Flight planning and navigation' guide.

2.1 Radiotelephony pronunciation (AIP GEN 3.4 section 4)

A phonetic alphabet is used in radiotelephony [R/T] communications when transmission of individual letters is required. This phonetic alphabet was originally developed by the North Atlantic Treaty Organisation as an international alphabet for use by the armed forces of the NATO nations.
PhoneticPronunciation    PhoneticPronunciation
A    ALFA AL fah     B     BRAVO BRAH voh
C    CHARLIE CHAR lee     D    DELTA DELL tah
E    ECHO ECK ho    F    FOXTROT FOKS trot
G    GOLF GOLF     H     HOTEL hoh TELL
I    INDIA IN dee A    J     JULIETT JEW lee ETT
K    KILO KEY loh     L     LIMA LEE mah
M    MIKE MIKE     N     NOVEMBER no VEM ber
O    OSCAR OSS cah     P    PAPA pah PAH
Q    QUEBEC keh BECK     R    ROMEO ROW me oh
S    SIERRA see AIR rah     T    TANGO TANG go
U    UNIFORM YOU nee form    V    VICTOR VIK tah
W    WHISKY WISS key     X    X-RAY ECKS ray
Y    YANKEE YANG key    Z    ZULU ZOO loo
The R/T pronunciation of numbers should be the following phonetic form:

0    ZE–RO        5     FIFE
1    WUN        6     SIX
2    TOO        7     SEV en
3    TREE         8     AIT
4    FOW er        9    NIN er
Hundred    HUN dred
Thousand    TOU SAND
Decimal    DAY SEE MAL
Expressing numbers
All numbers used in the transmission of altitude, cloud height and visibility information — that contain whole hundreds and whole thousands — must be transmitted by pronouncing each digit in the number of hundreds or thousands followed by the word HUNDRED or THOUSAND as appropriate, but without the suffix 'feet'; e.g.:
    (800 feet) – "EIGHT HUNDRED"
    (1500 feet) – "ONE THOUSAND FIVE HUNDRED"
    (4750 feet) – "FOUR SEVEN FIVE ZERO"
    (10 000 feet) – "ONE ZERO THOUSAND"

    (2200 feet )– "TWO THOUSAND TWO HUNDRED"

    (1500 feet) – "ONE THOUSAND FIVE HUNDRED"
    (3000 feet) – "THREE THOUSAND"
All other numbers, except VHF frequencies, must be transmitted by pronouncing each digit separately; e.g.:
  • HEADING (the words 'degrees' and 'magnetic' are not transmitted):
    (150 M) – "ONE FIVE ZERO"
    (080 M) – "ZERO EIGHT ZERO"
    (305 M) – "THREE ZERO FIVE"

  • WIND DIRECTION (the word 'degrees' is transmitted):
    (210) – "TWO ONE ZERO DEGREES"

    (10 knots) – "ONE ZERO KNOTS"
    (15 knots, gusting to 25) – "ONE FIVE KNOTS GUSTING TWO FIVE"

    (995 hPa) – "NINE NINE FIVE"
    (1010 hPa) – "ONE ZERO ONE ZERO"
    (1027 hPa) – "ONE ZERO TWO SEVEN"
VHF frequencies are a bit unusual because 25 kHz spacing is gradually being introduced in Australia as frequency congestion becomes apparent. However, currently only 50 kHz spacing operates in Class G airspace.
  • If the frequency is a 50 kHz multiple then all significant digits are transmitted including the first zero after the decimal point:
    (122.0) – "ONE TWO TWO DECIMAL ZERO"
  • If the frequency is a 25 kHz multiple (i.e. the second and third digits after the decimal point are 25 or 75) then the sixth digit is inferred as 'FIVE' and not transmitted:
    (122.025) – "ONE TWO TWO DECIMAL ZERO TWO"
    (122.525) – "ONE TWO TWO DECIMAL FIVE TWO'

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2.2 Expressing time (AIP GEN 3.4)

The 24-hour clock system is used in R/T transmissions. The hour is indicated by the first two figures and the minutes by the last two figures, e.g.:
  • (0001 hrs) – "ZERO ZERO ZERO ONE"
    (1920 hrs) – "ONE NINE TWO ZERO".
Time may be stated in minutes only (two figures) in R/T communications when no misunderstanding is likely to occur.

Current time in use at a station is stated to the nearest minute in order that pilots may use this information for time checks.

Australian civil aviation uses Coordinated Universal Time [UTC] for all operations. The suffix 'Zulu' is appended when procedures require a reference to UTC, e.g.:
  • (0920 UTC or 0920Z) – "ZERO NINE TWO ZERO ZULU"
    (0115 UTC or 0115Z) – "ZERO ONE ONE FIVE ZULU".
To convert from Australian Standard Time to UTC:
  • Eastern Standard Time subtract 10 hours
  • Central Standard Time subtract 9.5 hours
  • Western Standard time subtract 8 hours.

2.3 Standard words and phrases (AIP GEN 3.4)

The following words and phrases are to be used in radiotelephony communications, as appropriate, and have the meaning given:

ACKNOWLEDGE Let me know that you have received and understood this message.
APPROVED Permission for proposed action granted.
BREAK I hereby indicate the separation between portions of the message (to be used where there is no clear distinction between the text and other portions of the message).
CANCEL Annul the previously transmitted clearance.
CHECK Examine a system or procedure (no answer is normally expected).
CLEARED Authorised to proceed under the conditions specified.
CONFIRM Have I correctly received the following ... ? or
Did you correctly receive this message ... ?
CONTACT Establish radio contact with ...
CORRECT That is correct.
CORRECTION An error has been made in this transmission (or message indicated) the correct version is ...
DISREGARD Consider that transmission as not sent.
HOW DO YOU READ What is the readability (i.e. clarity and strength) of my transmission?
See 'clarity of transmission'.
I SAY AGAIN I repeat for clarity or emphasis.
MAINTAINContinue in accordance with the condition(s) specified or in its literal sense, e.g. "Maintain VFR".
MAYDAYMy aircraft and its occupants are threatened by grave and imminent danger and/or I require immediate assistance.
MONITOR Listen out on (frequency).
NEGATIVE "No" or "Permission is not granted" or "That is not correct".
OVER My transmission is ended and I expect a response from you ( not normally used in VHF communication).
OUT My transmission is ended and I expect no response from you ( not normally used in VHF communication).
PAN PANI have an urgent message to transmit concerning the safety of my aircraft or other vehicle or of some person on board or within sight but I do not require immediate assistance.
READ BACK Repeat all, or the specified part, of this message back to me exactly as received.
REPORT Pass me the following information.
REQUEST I should like to know or I wish to obtain.
ROGER I have received all of your last transmission
(Under NO circumstances to be used in reply to a question requiring READ BACK or a direct answer in the affirmative or negative. Do not use the term 'COPY THAT' or double click the transmit button.)
SAY AGAIN Repeat all or the following part of your last transmission
SPEAK SLOWER Reduce your rate of speech.
STANDBY Wait and I will call you.
VERIFY Check and confirm with originator.
WILCO I understand your message and will comply with it. (Do not use the term 'COPY THAT' or double click the transmit button.)
Clarity of transmission
The response to the query 'HOW DO YOU READ?' or 'REQUEST RADIO CHECK' is phrased in accordance with the following readability scale:
  1. Unreadable
  2. Readable now and then
  3. Readable but with difficulty
  4. Readable
  5. Perfectly readable.
The phraseologies to be used in communications between ATS and pilots in various circumstances are detailed in AIP GEN 3.4 section 5.

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Groundschool – VHF Radiocommunications Guide

| Guide content | Abbreviations and acronyms |

| 1. Transmitter licensing | [2. R/T phrasing] | 3. VHF characteristics and radio operation |

| 4. Microair 760 transceiver | 5. R/T procedures | 6. Safety and emergency procedures |

| 7. Aviation Distress Beacons | 8. Understanding SAR services |

Next – VHF characteristics The next section of the VHF radiocommunications guide outlines VHF transmission characteristics and the operation of equipment.