Air-ground communications in aviation generally consist of a series of instructions. These instructions may be intended for one aircraft rather than another, may include numbers, and may sometimes be unclear. For this reason, confusion and errors can occur, with serious consequences. The use of appropriate phraseology in radiotelephone communications between air traffic controllers and pilots is essential to the safe, rapid, and orderly flow of air traffic. This phraseology, which complies with radiotelephony procedures for general air traffic, is to be used in addition to conventional expressions.
All numbers are underlined. By convention, they should be read as shown in the following examples:
| 1 | unit | one |
| 1 2 | unit two | one two |
| 12 | twelve | twelve |
| 123 | one hundred and twenty-three | one hundred twenty-three |
| 12:35 | twelve thirty-five | twelve thirty-five |
| 7 37 | seven thirty-seven | seven thirty-seven |
When a number representing a frequency includes a comma, it is expressed as a decimal.
Special rule for the French language
A number can be conveyed as it is spoken in everyday life, or as a sequence of numbers.
Examples: 45 forty-five 1217 twelve, seventeen 210 two hundred and ten 5643 fifty-six, forty-three 1012 one thousand and twelve
As soon as the legibility of transmissions is unsatisfactory and/or in the event of ambiguity, the general rule applies
In French, as in many other languages, certain letters are pronounced similarly, which can lead to confusion: M and N, T and D, F and S, and so on. For this reason, every letter in phraseology must be pronounced according tothe aeronautical alphabet, which was defined in 1957 based on the English military alphabet of 1943. A is pronounced Alpha, B is pronounced Bravo, C is pronounced Charlie, and so on. M is pronounced Mike and is naturally distinct from N, November. The same applies to “Tango” and “Delta.” Having a standardized, well-defined alphabet ensures that the chosen words do not themselves lead to confusion (e.g., “C” for “Chemise” and “D” for “Denise”). List of letters in the alphabet:
| Alpha | Foxtrot | Kilo | Dad | Uniform | Zulu |
| Well done | Golf | Lima | Quebec | Victor | |
| Charlie | Hotel | Mike | Romeo | Whiskey | |
| Delta | India | November | Sierra | X-ray | |
| Echo | Juliett | Oscar | Tango | Yankee |
– Capital letters separated by a hyphen should be listed in alphabetical order:
I_L_S is pronounced i, l, s
– Capital and underlined letters must be spelled in accordance with the spelling code provided in the appendix to the decree on radiotelephone procedures for general air traffic:
A B says “alpha bravo”
– A sequence of non-underlined capital letters is read as the word thus formed:
MERLU means hake
When a clear language name has been assigned to a radio navigation aid, that is the name to use. This name is presented as a series of uppercase letters enclosed in quotation marks.
Example: “MTL” stands for Montélimar
Note: This is the Montélimar-Ancona VOR.
The VOR (short for
VHF Omnidirectional Range
) is a radio positioning system used in air navigation and operating on VHF frequencies (or UHF for military use).
In the absence of a plain-language name, a radionavigation aid is represented as a series of underlined capital letters.
In this case, the name of the radio helper must be spelled in accordance with the spelling code in the appendix to the decree on radiotelephone procedures for general air traffic use.
Example: B L M says: Bravo Lima Mike/Bravo Lima Mike
Note: This is a VOR/DME that has not been given a plain-language name.
| French pronunciation: | English pronunciation: | |
| ACAS | A_CAS | A_CAS |
| ACC | A_C_C | A_C_C |
| AFIS | A_FIS | A_FIS |
| APP | Approach | Approach |
| ATFM | A_T_F_M | A_T_F_M |
| ATIS | A_TIS | A_TIS |
| ATS | A_T_S | A_T_S |
| CAVOK | CAV_O_Kay | CAV_O_Kay |
| Cb | Ci_Bi / Cumulonimbus | C_B |
| CCR | C_C_R | |
| CTOT | C_TOT / C_T_O_T | C_TOT / C_T_O_T |
| DME | D_M_E | D_M_E |
| ELT | English pronunciation | E_L_T |
| FIR | FIR | F_I_R |
| PAH | H_A_P | Expected arrival time |
| HF | H_F | H_F |
| IFR | I_F_R | I_F_R |
| ILS | I_L_S | I_L_S |
| BMI | I_M_C | I_M_C |
| LVP | L_V_P | Low-visibility procedures |
| MSAW | English pronunciation | M_SAW |
| NDB | N_D_B | N_D_B |
| NM | Nautical | Miles |
| NOTAM | NOTAM | NOTAM |
| QFE | Q_F_E | Q_F_E |
| QFU | Q_F_U / Runway in use | Runway in use |
| QNH | Q_N_H | Q_N_H |
| RVR | R_V_R | R_V_R |
| RVSM | R_V_S_M | R_V_S_M |
| SIV | S_I_V | S_I_V |
| SSR | S_S_R | S_S_R |
| TCAS | T_CAS | T_CAS |
| TMA | T_M_A | T_M_A |
| TWR | Tower | Tower |
| UHF | U_H_F | U_H_F |
| UIR | U_I_R | U_I_R |
| UTC | U_T_C | U_T_C |
| VFR | V_F_R | V_F_R |
| VHF | V_H_F | V_H_F |
| VMC | V_M_C | V_M_C |
| VOR | VOR / V_O_R | V_O_R |
Please note that whenever the legibility of transmissions is unsatisfactory and/or in the event of ambiguity, numbers are transmitted by spelling out each of their digits.
Example: Altitude 3,500 feet: three five zero zero
3,500 feet: three five zero zero
Terms used:
Distress messages:
Regardless of the language used, distress messages are preceded by the phrase ” mayday“
Emergency messages:
Regardless of the language used, emergency messages are preceded by the phrase “
” pan pan / pan pan. This category of messages includes medical transport messages preceded by the phrase “pan pan medical.”
Frequency to be used
For the theory certificate, you need to know the frequency to use in the event of distress.
The distress message is transmitted on the air-ground frequency in use.
The distress message may be transmitted on frequency 121.500 MHz or onany other frequency in the aeronautical or maritime mobile service if deemed necessary or desirable.
List of frequencies:
The frequency range allocated to aviation extends from 108 MHz to 137 MHz in the VHF band, divided as follows:
- 108 MHz to 111.975 MHz: ILS
- 111.975 MHz to 117.950: VOR
- 117.975 to 137 MHz: Aeronautical Mobile Service, i.e., voice communications.
Special frequencies:
- 121.500 MHz: international distress frequency.
- 123.500 MHz: “club” frequency, allocated to aerodromes that do not have enough traffic to warrant their own frequency.
- 123.450 MHz: communication between aircraft.
Emergency beacons:
They transmit in the 406 to 406.1 MHz band and send search and rescue teams a coded digital message identifying the beacon and the aircraft owner or operator. This message can also indicate the beacon’s position.
For more information on communication:
https://www.sia.aviation-civile.gouv.fr/pub/media/reglementation/file/r/a/radiotel_v3.pdf
The different phases: uncertainty—alert—distress
ICAO Annex 11 defines three levels—the uncertainty phase, the alert phase, and the distress phase—as follows
– The “uncertainty” phase, known as INCERFA, corresponds to a situation in which there is reason to doubt the safety of an aircraft and the people on board. In particular, such an alert must be triggered when no communication has been received from an aircraft within 30 minutes of the time at which a communication should have been received, or when an aircraft does not arrive within 30 minutes of the last estimated time of arrival (ETA) notified to air traffic control authorities;
– The “alert” phase, known as ALERFA, corresponds to a situation in which there is reason to fear for the safety of an aircraft. An alert phase must be triggered when, following the uncertainty phase, attempts to contact the aircraft have yielded no information; when an aircraft that has received clearance to land fails to land within 5 minutes of the scheduled landing time; when the information received indicates that the aircraft’s operation is compromised; or when the aircraft is known or believed to be the target of unlawful interference;
– The “distress” phase, known as DETRESFA, corresponds to a situation in which there is every reason to believe that an aircraft is facing serious and imminent danger and requires immediate assistance. Such an alert is issued when further attempts to contact the aircraft and inquiries from various appropriate sources indicate that the aircraft is likely in distress, as well as when it is determined that it must have run out of fuel.
