RADIOTELEPHONY BASICS

1. General operating procedures.

Radiotelephony (RTF) provides the means by which pilots and ground personnel communicate with each other. The information and instructions transmitted are of vital importance in the safe and expeditious operation of aircraft. 

Incidents and accidents have occurred in which a contributing factor has been the use of non-standard procedures and phraseology. The importance of using correct and precise standardized phraseology cannot be overemphasized.

2. Transmitting techniques .

The following transmitting techniques will assist in ensuring that transmitted speech is clear: 

• Listen out on the frequency some seconds before transmitting to ensure that there will be no interference with a transmission from another station
• Press the transmit switch fully before speaking and do not release it until the message is completed. This will ensure that the entire message is transmitted
• Use a normal conversational tone, and speak clearly and distinctly and maintain the speaking volume at a constant level 
• Make a slight pause before and after numbers will assist in making them easier to understand 
• Avoid using hesitation sounds such as "er"
• Suspend speech temporarily if it becomes necessary to turn the head away from the microphone When switching to a new frequency, using TeamSpeak, the active transmission can be not heard all the time. So, it is important to listen first before transmitting. 

3. Transmission of letters.

With the exception of the telephony designator and the type of aircraft, each letter in the aircraft call sign shall be spoken separately using the phonetic spelling.

Word	Pronunciation	IPA from ICAO	Word	Pronunciation	IPA from ICAO
A - ALFA	AL fah	ˈælfɑ	N - NOVEMBER	no VEM ber	noˈvembə
B - BRAVO	BRAH voh	ˈbrɑːˈvo	O - OSCAR	OSS car	ˈɔskɑ
C - CHARLIE	CHAR lee OR SHAR lee	ˈtʃɑːli or ˈʃɑːli	P - PAPA	pah PAH	pəˈpɑ
D - DELTA	DELL tah	ˈdeltɑ	Q - QUEBEC	keh BECK	keˈbek
E - ECHO	ECK oh	ˈeko	R - ROMEO	ROW me oh	ˈroːmiˑo
F - FOXTROT	FOKS trot	ˈfɔkstrɔt	S - SIERRA	see AIR rah	siˈerɑ
G - GOLF	golf	ɡʌlf [sic]	T - TANGO	TANG go	ˈtænɡo [sic]
H - HOTEL	hoh TEL	hoːˈtel	U - UNIFORM	YOU nee form OR OO nee form	ˈjuːnifɔːm or ˈuːnifɔrm [sic]
I - INDIA	IN dee ah	ˈindiˑɑ	V - VICTOR	VIK tah	ˈviktɑ
J - JULIET	JEW lee ETT	ˈdʒuːliˑˈet	W - WHISKEY	WISS key	ˈwiski
K - KILO	KEY loh	ˈkiːlo	X - X-RAY	ECKS ray	ˈeksˈrei
L - LIMA	LEE mah	ˈliːmɑ	Y - YANKEE	YANG key	ˈjænki [sic]
M - MIKE	mike	mɑik	Z - ZULU	ZOO loo	ˈzuːluː

To expedite communications, the use of phonetic spelling should be dispensed with if there is no risk of this affecting correct reception and intelligibility of the message.

4. Transmission of numbers.

Number	Pronunciation
0 ZE-RO	7 SEV en
1 WUN	8 AIT
2 TOO	9 NIN er
3 TREE	Decimal DAY SEE MAL
4 FOW er	Hundred HUN dred
5 FIFE	Thousand TOU SAND
6 SIX

The syllables printed in capital letters are to be stressed.

4.1. Transmission by pronouncing each digit separately.

The numbers in the table below shall be transmitted by pronouncing each digit separately:

Aircraft call signs	Transmitted as
CCA 238	Air china two three eight
OAL 242	Olympic two four two

Flight level	Transmitted as
FL 180	Flight level one eight zero
FL 200	Flight level two zero zero

Heading	Transmitted as
100°	heading one zero zero
080°	heading zero eight zero

Wind direction / speed	Transmitted as
200° 25kt	Wind two zero zero degrees two five knots
160° 18kt	Wind one six zero degrees one eight knots

Transponder codes	Transmitted as
2400	Squawk two four zero zero

Runway	Transmitted as
27	Runway two seven
30	Runway three zero

Altimeter	Transmitted as
1010	One zero one zero
1000	One zero zero zero
999	Nine nine nine

4.2. Transmission by pronouncing digit.

All numbers used in the transmission of altitude, cloud height, visibility and runway visual range (RVR) information, which contain whole hundreds and whole thousands, shall be transmitted by pronouncing each digit in the number of hundreds or thousands followed by the word HUNDRED or THOUSAND as appropriate. 

altitude	Transmitted as
800 ft	eight hundred
3400 ft	three thousand four hundred
12000 ft	one two thousand

cloud height	Transmitted as
1000 ft	visibility one thousand
700 ft	visibility seven hundred

runway visual range	Transmitted as
600 m	RVR six hundred
1700 m	RVR one thousand seven hundred

4.3. Transmission of frequency.

All six digits of the numerical designator should be used to identify the transmitting channel in VHF radiotelephony communications, except in the case of both the fifth and sixth digits being zeros, in which case only the first four digits should be used:

Channel	Transmitted as
118.000	ONE ONE EIGHT DECIMAL ZERO
118.005	ONE ONE EIGHT DECIMAL ZERO ZERO FIVE
118.010	ONE ONE EIGHT DECIMAL ZERO ONE ZERO

118.025	ONE ONE EIGHT DECIMAL ZERO TWO FIVE
118.050	ONE ONE EIGHT DECIMAL ZERO FIVE ZERO
118.100	ONE ONE EIGHT DECIMAL ONE
118.105	ONE ONE EIGHT DECIMAL ZERO ONE FIVE

4.4. Transmission of time.
Only the minutes of the hour should normally be required to transmit time. Each digit should be pronounced separately. However, the hour should be included when any possibility of confusion is possible. 

Time	Transmitted as
0920 (09:20am)	TWO ZERO ZERO NINE TWO ZERO
1643 (4:43pm)	FOUR THREE ONE SIX FOUR THREE

5. Radiotelephony standard words. 

ACKNOWLEDGE	Let me know that you have received and understood this message.
AFFIRM	Yes.
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.
MAINTAIN	Continue in accordance with the condition(s) specified or in its literal sense, e.g. "Maintain VFR".
MAYDAY	My 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 PAN	I 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.)

6. Establishing communication.

6.1. First contact.

When establishing communications, a pilot initial call shall contain: 

• Designation of the station being called (active controller)
• Call sign of his aircraft, with the word “heavy” for aircraft in the heavy wake turbulence category
• Position (on the apron or on route)
• Additional elements required by controllers (like ATIS information letter, ATC restriction or last clearance to report)

Pilot : Highvilla tower, DEHBA, at general aviation parking, information KILO on board.
ATC : DEHBA, Highvilla tower, hello. 

The pilot usually tranmits his call sign at the end of the message, as the air traffic controller may handle many aircraft at the same time. The pilots identify themselves using their unique call signs.

An ATC shall begin his message with the concerned pilot call sign to be sure that the right pilot carefully listens in the clearances given. An ATC is not required to transmit his call sign. He can do it at the first contact or when the pilots misspell his call sign.

6.2. Issue of clearance .

Whenever possible, a route clearance should be passed to an aircraft before start up. Controllers should avoid passing a clearance to a pilot engaged in complicated taxiing maneuvers and on no occasion should a clearance be passed when the pilot is engaged in line up or take-off manoeuvres.

Controllers should pass a clearance slowly and clearly since the pilot needs to write it down and wasteful repetition will thus be avoided.

An air traffic control (ATC) route clearance is not an instruction to take off or enter an active runway.

The words "TAKE OFF" are used only when an aircraft is cleared for take-off, or when cancelling a take-off clearance. At other times, the word "DEPARTURE" or "AIRBORNE" is used.

6.3. Read back requirements.

Read-back requirements have been introduced in the interest of flight safety.

The stringency of the read-back requirement is directly related to the possible seriousness of a misunderstanding in the transmission and receipt of ATC clearances and instructions.

Strict adherence to read-back procedures ensures not only that the clearance has been received correctly but also that the clearance was transmitted as intended. It serves as a check that the right aircraft, and only that aircraft, will take action on the clearance.

The following shall always be read back:

• ATC route clearances 
• clearances and instructions to enter, land on, take off from, hold short of, cross and backtrack on any runway 
• runway-in-use, altimeter settings, SSR codes, level instructions, heading and speed instructions 
• transition level 

An aircraft should terminate the read-back by its call sign.

Examples of read back:

ATC : DEHBA, taxi holding point runway 01  

Pilot : taxi holding point runway 01, DEHBA

ATC : DEHBA, squawk 4525

Pilot : 4525, DEHBA

If an aircraft read-back of a clearance or instruction is incorrect, the controller shall transmit the word "NEGATIVE I SAY AGAIN" followed by the correct version:

ATC : DEHBA, QNH 1003  

Pilot : QNH 1033, DEHBA

ATC : DEHBA, Negative I say again, QNH 1003

Pilot : QNH 1003, DEHBA

6.4. Test procedure.

When a communication with an air traffic controller seems to be difficult, a pilot can use a radio communication test procedure: 

Test transmissions should take the following form as a pilot: 

1. the identification of the aeronautical station being called; 

2. your aircraft identification; 

3. the words "RADIO CHECK" 

4. the frequency being used. 

Replies to test transmissions should be as follows: 

1. the identification of the station calling; 

2. the identification of the station replying; 

3. Level of reception regarding the readability of the transmission.

Readability of the transmission: Level of reception 

Unreadable: 1 

Readable now and then: 2 

Readable but with difficulty: 3 

Readable: 4 

Perfectly readable: 5

You can learn by yourself with the material below:
- RADIOTELEPHONY Materials
- Live ATC