Radiotelephony
Radiotelephony (shortened to RTF) is the practice of speaking on the radio. Because of generally quite low audio quality, and the requirement to speak to those for whom English is not their native language, certain words are used in place of others, and many have more specific definitions than their general English definitions. These are called "Prowords" - short for "Procedural Words". RTF also refers to the way in which information is passed over the radio, and how
Note
While designed for brevity and ease of communication, RTF Prowords are not what we normally call brevity (a shortening of tactical brevity codes), for the sake of this document, "brevity" has its everyday English definition, in the sense of "being brief"
DRIPS
DRIPS is an acronym that can be used to remember the different parts of your voice you can change to adapt your transmission to the situation:
- Diction
- Rhythm
- Intensity
- Pitch
- Speed
However, you MUST speak clearly and distinctly to allow yourself to be understood
General Procedures
Transmitting Technique
When you're operating a radio, try not to turn your head away from your microphone, or vary the distance between it and your mouth. Distortion could arise from:
- talking too close to the microphone
- touching the microphone with the lips
- holding the microphone or boom
When it is known that elements of the message will be written down by the recipients speak at a slightly slower rate and maintain a consistent volume
Transmission of Letters
When transmitting letters, the International Radiotelephony Spelling Alphabet, documented below (emphasised syllables are in bold):
| Letter | Word | Appropriate Pronunciation |
|---|---|---|
| A | Alpha | AL FAH |
| B | Bravo | BRAH VOH |
| C | Charlie | CHAR LEE or SHAR LEE |
| D | Delta | DELL TAH |
| E | Echo | ECK OH |
| F | Foxtrot | FOKS TROT |
| G | Golf | GOLF |
| H | Hotel | HO TELL |
| I | India | IN DEE AH |
| 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 or OO NEE FORM |
| V | Victor | VIK TAH |
| W | Whisky | WISS KEY |
| X | X-ray | ECKS RAY |
| Y | Yankee | YANG KEE |
| Z | Zulu | ZOO LOO |
Transmission of Numbers
| Numeral or numeral element | Latin alphabet representation |
|---|---|
| 0 | ZERO |
| 1 | WUN |
| 2 | TOO |
| 3 | TREE |
| 4 | FOW ER |
| 5 | FIFE |
| 6 | SIX |
| 7 | SEV EN |
| 8 | AIT |
| 9 | NIN ER |
| Decimal | DAYSEEMAL |
| Hundred | HUN DRED |
| Thousand | TOUSAND |
The following numbers should be transmitted by pronouncing each digit separately:
- aircraft callsigns
- altimeter settings
- flight levels (with the exception of FL 100, 200, 300 etc.)
- headings
- wind speeds/directions
- airspeed
- frequencies
Examples of this are as follows:
| Number | Transmitted as | Pronounced as |
|---|---|---|
| BAW246 | Speedbird Two Four Six | SPEEDBIRD TOO FOWER SIX |
| FL100 | Flight Level One Hundred | FLIGHT LEVEL WUN HUN DRED |
| FL180 | Flight Level One Eight Zero | FLIGHT LEVEL WUN AIT ZERO |
| 150 Degrees | One Five Zero Degrees | WUN FIFE ZERO DEGREES |
| 18 Knots | One Eight Knots | WUN AIT KNOTS |
| 122.1 | One Two Two Decimal One | WUN TOO TOO DAYSEEMAL WUN |
| (Squawk) 6500 | Six Five Zero Zero | SIX FIFE ZERO ZERO |
The following numbers should be transmitted by prouncing each digit in the number of hundreds or thousands followed by the word HUNDRED or TOUSAND as appropriate, IF they contain whole hundreds and whole thousands:
- altitude
- height
- cloud height
- pressure setting
- transponder codes
- visibility
- runway visual range
| Number | Transmitted as | Pronounced as |
|---|---|---|
| 10 | One Zero | WUN ZERO |
| 100 | One Hundred | WUN HUN DRED |
| 2,500 | Two Thousand Five Hundred | TOO TOUSAND FIFE HUNDRED |
| QNH 1000 hPa | One Thousand | WUN TOUSAND |
| (squawk) 1000 | One Thousand | WUN TOUSAND |
| 11,000 | One One Thousand | WUN WUN TOUSAND |
| 25,000 | Two Five Thousand | TOO FIFE TOUSAND |
When transmitting an altimeter setting in inHg, the word DAYSEEMAL may be omitted if it does not impede understanding.
Note
A good rule of thumb for this is the first call DAYSEEMAL is omitted, and if an incorrect value is read back it should be included.
Prowords
| Word/Phrase | Meaning |
|---|---|
| ACKNOWLEDGE | Let me know that you have received and understood this message |
| AFFIRM | Yes |
| ALL STATIONS | This message is indended to be received by all stations on this frequency |
| APPROVED | Permission for proposed action granted |
| BREAK | Indicates the separation between messages |
| BREAK BREAK | Indicates the separation between messages transmitted to different aircraft in a busy environment |
| CANCEL | Annul the previously transmitted clearance |
| CHECK | Examine a system or procedure (not to be used in any other context. No answer is normally expected) |
| CLEARED | Authorised to proceed under the conditions specified |
| CLIMB | Increase altitude and maintain |
| CONFIRM | I request verification of: (clearance, instruction, action, information) |
| CONTACT | Establish communications with... (your details have been passed) |
| CORRECT | True or accurate |
| CORRECTION | An error has been made in this transmission (or message indicated). The correct version is... |
| DESCEND | Decrease altitude and maintain |
| DISREGARD | Ignore |
| FANSTOP | I am initiating practice engine failure after takeoff. (used only by pilots of single engine aircraft). The response should be "REPORT CLIMBING AWAY" |
| FREECALL | Call... (unit) (your details have not been passed - mainly used by military ATC) |
| HOLD SHORT | Stop before reaching the specified location (only used when there is no suitably located holding point) |
| HOW DO YOU READ | What is the readability of my transmission? |
| I SAY AGAIN | I repeat for clarity or emphasis |
| MAINTAIN | Continue in accordance with the conditions specified, or in its literal sense |
| MONITOR | Listen out on (frequency) |
| NEGATIVE | No; or Permission not granted; or that is not correct; or not capable |
| NEGATIVE I SAY AGAIN | May be used if repeated incorrect readbacks are given by the pilot and additional emphasis is required |
| OUT | This exchange of transmissions is ended and no response is expected (not normally used in aviation transmissions) |
| OVER | My transmissied is ended and I expect a response from you (not normally used in aviation transmissions) |
| 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 your last transmission (NOT to be used in reply to a question requiring a direct answer in the affirmative or negative) |
| SAY AGAIN | Repeat all, or the following part of your last transmission |
| SPEAK SLOWER | Reduce your rate of speach |
| STANDBY | Wait and I will call you |
| UNABLE | I cannot comply with your request, instruction or clearance (normally followed by a reason) |
| WILCO | I understand your message and will comply with it (abbreviation for will comply) |
| WORDS TWICE | As a request: Communication is difficult Please send every word twice. As Information: Since communication is difficult, every word in this message will be sent twice |
Aeronautical Service Callsigns
Definition!
A station is anyone with the ability to transmit/receive on a radio frequency, may include:
- aircraft stations
- ground stations (controllers, airport vehicles etc.)
- ship stations
Definition!
A callsign is a 'name' that is given to a station which is then used to identify that station. Callsigns should be unique on each radio frequency (i.e. you can't have multiple Viper 1-1s on the same frequency).
| Service | Suffix |
|---|---|
| Area Control | CONTROL |
| Radar (in general) | RADAR |
| Approach Control | APPROACH |
| Aerodrome Control | TOWER |
| Approach Control Radar Arrival/Departure | DIRECTOR/DEPARTURE (RADAR when tasks combined)/ARRIVAL (when approved) |
| Ground Movement Control | GROUND |
| Precision Approach Radar | TALKDOWN |
| Flight Information | INFORMATION |
| Air/Ground Communication Service | RADIO |
| Clearance Delivery | DELIVERY |
Military Formation Callsigns
Formation callsigns facilitate control of multiple aircraft within one speaking unit. These are usually a single word, and a single number (often followed by the suffix FLIGHT)A
- VIPER 1 - Formation
- VIPER 1 FLIGHT - Formation
- VIPER 1-1 FLIGHT - Formation
- VIPER 1-1 - Single aircraft
Under normal circumstances, formations may be controlled as if they are a single aircraft.
The Transmission Format
To aid in communication, and brevity, each transmission will have a specified format.
The Initial Call
The initial call is designed to make the other station aware that you wish to pass them a message, after initial contact this is usually only done if the message cannot be transmitted in one breath.
For an initial call, both callsigns are stated one after the other, the callsign of the station you are calling, and your own callsign:
Anapa Ground
Viper 1-1, Anapa Ground.
The above example is Anapa Ground wishing to pass Viper 1-1 a message. To invite a response, the same RTF is used but with the callsigns in the other order (older documents may include the phrase "go ahead" or "pass your message", however, the most modern documents suggest these be omitted).
Viper 1-1
Anapa Ground, Viper 1-1.
A Traditional Call
A traditional call is the most well known format. Both callsigns are still stated, in the same order as an initial call, however, a message is also included. This format must be used when the transmitter/recipient of the message is not a controller (e.g. aircraft to aircraft) and may be used if there has not been any communication between a controller and another station for some time.
Rostov Control
Viper 1-1, Rostov Control, identified.
Truncated Calls
When on a controller's frequency, the controller's callsign may be implied, when another station makes a request, the format is similar to the traditional call, only the controller's callsign is omitted:
Viper 1-1
Viper 1-1, requesting descent.
The above example is Viper 1-1 requesting a descent clearance.
When a controller is giving an instruction/clearance to another station, the format is similar to the traditional call, only the controller's callsign is omitted:
Rostov Control
Viper 1-1, descend altitude 3,000.
When a station then reads back an instruction/clearance, the station's callsign is placed at the end of the transmission:
Viper 1-1
Descend altitude 3,000, Viper 1-1.
This sequence of calls effectively constitutes a 'conversation' (the request may be omitted), therefore, another conversation may begin once a callsign is placed at the end of a transmission.
Required Readbacks
Reading back information ensures that said information is transmitted and received accurately. The following messages MUST be read back by the aircraft:
- Taxi Instructions
- Level Instructions (i.e. CLIMB/DESCEND)
- Heading Instructions
- Speed Instructions
- Airways or Route Clearances
- Approach Clearances
- Runway-in-use
- Clearance to Enter, Land on, Take-Off on, Backtrack, Cross, or hold short of any Active Runway
- SSR Operating Instructions (squawk codes)
- Altimeter Settings
- VDF (VHF Direction Finding) Information
- Frequency Changes
- Transition Levels
Further Reading
The information here can be found in: