Radio Procedures and Phraseology

Drafted — not technically validated

Module revision 4 · Air–ground voice radio for pilots: how to transmit, how to say letters and numbers, how to make and answer calls, and what to do in an emergency or when the radio fails. Written for military pilots of every US service: military practice first (the multi-service brevity words shared by the Army, Marine Corps, Navy and Air Force, UHF and preset channels, and a worked Navy training sortie with its formation check-ins and training-rule calls), then the Federal Aviation Administration (FAA) rules that every military aircraft follows in US airspace.

Every figure is interactive. Step through a training sortie call by call, build calls, convert numbers into radio words, read back clearances, set a transponder without tripping an emergency code, and fly a lost-communications route.

Purpose and learning objectives

A military pilot's radio work has a joint layer and a local one. The brevity words are common to all four services, and many military aircraft talk to controllers on UHF, which most civil aircraft cannot hear. [4, p. i] [5, p. 2] The calls around the airfield are set by each service, wing, squadron and base. This module's worked example is one Navy training squadron's: a day on the radio runs from the squadron's base frequency to clearance, ground, tower, departure, the working area and back, mostly on preset UHF channels, with a short call sign that changes from flight to flight. [1, pp. 19–35] Inside US airspace those calls follow the FAA's rules, so this module teaches both: the military flow first, then the FAA phraseology underneath it. Radio is the critical link between pilots and air traffic control (ATC). The FAA's Aeronautical Information Manual (AIM) asks pilots to keep transmissions brief, to acknowledge each ATC communication with the aircraft's call sign, and to prefer standard phraseology over jargon and slang. [6, para 4-2-1] Good radio work is mostly listening: knowing what was said, to whom, and what you must do about it.

By the end you should be able to: use the multi-service brevity words and the training-rule calls that stop and start an engagement; follow a training sortie's calls from the squadron base frequency to the break and back; transmit cleanly without blocking the frequency; spell with the phonetic alphabet; say altitudes, headings, speeds, frequencies and times the way the AIM does; make an initial call in the right order; choose the right acknowledgement word; read back the parts of a clearance that must be read back; follow a formation check-in and frequency push; make a distress call; change a transponder code without passing through an emergency code; and fly the AIM's lost-communications rules.

This is a reference, not a substitute for your aircraft's flight manual (NATOPS, -1 or operator's manual), your service's, wing's and squadron's procedures, or the current AIM. The sortie and formation examples come from Navy training squadrons because their scripts are published; Air Force, Army and Marine Corps units use the same FAA phraseology in US airspace with their own local procedures, and frequencies, channels, call signs and local calls differ by unit and base. Ships and other countries use additional or different procedures. Carrier recovery communications are in the Case III module's radio section, which steps through a Case III approach call by call. Who to call, and when, around a military field and at civil towered and non-towered airfields, with the overhead break and pattern they go with, is in Airfield Operations.

Radio technique

The AIM's radio technique comes down to six habits. [6, para 4-2-2]

Listen before you transmit. Much of what you need may come from ATIS or from monitoring the frequency. If you hear someone else talking, keying your transmitter is futile: you will probably jam their receivers and make them repeat their call. After changing frequency, pause and listen to make sure it is clear.
Think before keying your transmitter. Know what you want to say; write a long message, such as an IFR position report, down first.
Press, pause, then speak. Hold the microphone close to your lips; a slight pause after pressing the button may be necessary to be sure the first word is transmitted. Speak in a normal, conversational tone.
Wait before calling again. After releasing the button, wait a few seconds before calling again: the controller may be writing down your call sign, looking for your flight plan, or working another frequency.
Listen to your receiver. Be alert to the sounds, or the lack of sounds, in your receiver; check the volume and frequency, and make sure your microphone is not stuck on transmit. A stuck microphone can block a frequency for long periods.
Be within range. Make sure you are within the performance range of your radio equipment and the ground station equipment. At some sites you can hear the station but it cannot hear you, and higher altitude extends VHF line-of-sight range.

A quiet frequency is not always a clear one. Pilots acknowledge each ATC communication, [6, para 4-2-1] so after a controller's instruction, or a pilot's request, an answer is owed, and the pause before it belongs to that exchange. In the worked Navy sortie, most of the controllers' calls are answered at once by the pilot's readback. [1, pp. 19–35] Keying into that pause either steps on the answer or makes the controller hold you while the exchange finishes. Once the frequency is quiet and nothing is owed, call: anyone who has not keyed yet hears you and waits for your exchange to finish, as you waited for theirs.

Figure 1 — Get a word in on a busy frequency

You are KATT 31, just switched to Approach, which is working a Navy jet, an Army helicopter and an Air Force airlifter. Your check-in takes three seconds. Play the frequency and press Transmit when the frequency is quiet and nobody owes a reply. As on a real radio you only hear what has already been said; the other stations hear you too, and those that have not keyed yet wait their turn.

Time on the frequency

Heard so far

Interactive figure unavailable. If you stay silent, the frequency runs: Approach to Navy 405, "turn left heading 270", and its readback; Army 26019 requests descent, Approach clears it to 3,000, and it reads back; Approach turns REACH 451, hears nothing for three seconds and calls again before REACH 451 answers; Approach sends Navy 405 to Tower and it reads back. Call after a readback, not in the pause after an instruction or a request.

Constructed illustration: the calls and timings are invented, and a station keying within half a second of you is taken not to have heard you. A call over someone already talking is futile and makes them repeat. [6, para 4-2-2] Waiting for an owed reply follows from acknowledging each ATC call [6, para 4-2-1]; the AIM does not spell it out.

Bands and emergency frequencies

Military air–ground voice uses the ultrahigh frequency (UHF) band, 300 to 3,000 MHz, which in some instances goes as low as 225 MHz. Civil air–ground voice uses the very high frequency (VHF) band, 30 to 300 MHz. [7, VHF; UHF] Many military aircraft use UHF to talk to controllers and to each other, so a civil pilot on VHF may not hear them. [5, p. 2] A military trainer usually carries both radios: in one training squadron's script the student works ATIS, clearance delivery, ground, tower, departure, approach and the squadron's own base frequency on UHF, and uses VHF to talk to a civil approach frequency and to cancel IFR. [1, pp. 19–31]

Frequencies are set up in advance as numbered preset channels, so a controller or the brief can name a channel instead of a frequency: in that script UHF channel 4 is Sherman Tower, and approach hands the aircraft off with "contact Sherman Tower Button 4". [1, pp. 25, 32] Your squadron's channel card sets the numbers; the ones here are that script's.

Two emergency frequencies matter to every pilot: 121.5 MHz (VHF) and 243.0 MHz (UHF). Both are generally limited to line of sight. 121.5 is guarded by direction-finding stations and some military and civil aircraft; 243.0 is guarded by military aircraft, so a military pilot in trouble has a UHF emergency frequency that other military aircraft are listening to. The frequency in use, or another ATC frequency, is still preferable for an emergency call. [6, para 6-3-1] 122.2 MHz is assigned to most flight service stations as a common en route simplex frequency. [6, para 4-2-14]

Figure 2 — Where the voice frequencies sit

Show 121.5 122.2 243.0 225

Interactive figure unavailable. 121.5 MHz (VHF emergency) and 122.2 MHz (flight service) sit in VHF; 243.0 MHz (UHF emergency) sits in UHF, above the 225 MHz lower edge of military UHF voice.

Linear scale, 100–400 MHz only. The figure does not show the civil VHF voice band's exact limits.

The phonetic alphabet

Use the International Civil Aviation Organization (ICAO) phonetic alphabet when communications conditions make letters hard to tell apart, when aircraft with similar call signs share a frequency, and to spell difficult words. Each letter has a telephony word and a pronunciation; the digits have their own pronunciations, such as TREE, FIFE and NIN-ER. [6, para 4-2-7]

Phonetic alphabet and Morse code [6, para 4-2-7]
Character	Telephony	Pronunciation	Morse
A	Alfa	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	HOH-TEL	····
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	Whiskey	WISS-KEY	·––
X	Xray	ECKS-RAY	–··–
Y	Yankee	YANG-KEY	–·––
Z	Zulu	ZOO-LOO	––··
1	One	WUN	·––––
2	Two	TOO	··–––
3	Three	TREE	···––
4	Four	FOW-ER	····–
5	Five	FIFE	·····
6	Six	SIX	–····
7	Seven	SEV-EN	––···
8	Eight	AIT	–––··
9	Nine	NIN-ER	––––·
0	Zero	ZEE-RO	–––––

Numbers on the radio

The AIM's rules for numbers: [6, paras 4-2-8–4-2-12]

Hundreds and thousands. Round hundreds and thousands up to 9,900 are spoken as words ("four thousand five hundred"). Above 9,900, the digits before "thousand" are spoken separately ("one zero thousand"). Airway and jet route numbers are spoken as letters and words (V12 is "Victor Twelve"). Other numbers are spoken digit by digit. A decimal point is "point"; ICAO uses "decimal", and the FAA accepts it from pilots required to use it.
Altitudes. Below 18,000 ft mean sea level (MSL), say the thousands and hundreds: "one two thousand five hundred". At and above 18,000 ft (flight level 180), say "flight level" and three digits.
Directions. Bearings, courses, headings and wind directions are three digits and magnetic; add "true" when it applies.
Speeds. Digit by digit, then "knots". Mach numbers: "Mach" and the digits with "point".
Time. Coordinated Universal Time (UTC) on the 24-hour clock, digit by digit; "Zulu" may be used to denote UTC.

The AIM's examples [6, paras 4-2-8–4-2-12]
Written	Spoken
500 ft	five hundred
4,500 ft	four thousand five hundred
10,000 ft	one zero thousand
13,500 ft	one three thousand five hundred
FL 190	flight level one niner zero
Heading 100	heading one zero zero
Wind 220	wind two two zero
050 true course	zero five zero true
190 kt	one niner zero knots
Mach 1.5	Mach one point five
122.1 MHz	one two two point one
0920 UTC	zero niner two zero

Figure 3 — Say it on the radio

Choose what you are saying and type it. The figure gives the words and, below them, the AIM pronunciation of each character.

What it isValue Aircraft type

Interactive figure unavailable. Use the rules and examples above: 13,500 ft is "one three thousand five hundred".

The converter applies the AIM rules above. It accepts altitudes in whole hundreds of feet, directions 001–360 and transponder codes of four digits 0–7. Abbreviated call signs keep the prefix (here the type) and the last three characters, and are used only after ATC abbreviates first.

Call signs

Military call signs. The AIM only says that military aircraft use a variety of call sign systems. [6, para 4-2-4] In Navy training the call sign is usually a squadron word and a number: the script's student is "KATT 11" for one flight and is told to use a different call sign for every practice event. [1, p. 20] The squadron answers on its own base frequency as "KATT Base", and the side number painted on the jet is passed separately, so the call sign names the flight, not the airframe: "KATT Base, KATT 11 taxi outbound, side number 000". [1, p. 20] A formation has one tactical call sign for the whole flight, "Angry" in one squadron's examples, and each aircraft answers with its position in the flight, "Angry 1-2". [2, pp. 2–3]

A military call sign is said as written: words, then the digits. The rest of this section is the FAA's rule set, which applies to everyone on a US civil frequency. Never abbreviate a call sign on initial contact, or when another aircraft on the frequency has a similar one. ATC may start abbreviating a call sign; after that the pilot may use the abbreviation, but ATC will not abbreviate the call signs of air carriers or other civil aircraft with authorized call signs. [6, para 4-2-4]

Civil aircraft: the aircraft type, model or manufacturer's name, then the registration characters. When the type is stated, the "N" prefix is dropped: "Aztec Two Four Six Four Alfa". An abbreviated call sign is the prefix and the last three characters. [6, para 4-2-4]
Air carriers use their authorized call sign and the flight number in group form, "United Two Twenty-Two", adding "Heavy" or "Super" when appropriate. [6, paras 4-2-3, 4-2-4]
Student pilots can identify themselves as students on initial contact for extra help from ATC. [6, para 4-2-4]

Ground stations are called by the facility's name followed by its type, such as "Sherman Ground" at a naval air station or "New York Radio" for a civil flight service station. [6, para 4-2-6] [1, p. 21]

Ground station call signs [6, para 4-2-6]
Facility	Name, then
Squadron base frequency (Navy training)	Squadron call sign, then "Base", e.g. "KATT Base" [1, p. 20]
Airport traffic control tower	"Tower"
Ground control	"Ground"
Clearance delivery	"Clearance Delivery"
Approach and departure control	"Approach", "Departure"
Flight service station	"Radio"
Air route traffic control center	"Center"
Airport UNICOM	"UNICOM"

A training sortie, call by call

The worked example is the Navy's, because its script is published. Other services' training wings publish their own local calls, and all of them work the same kinds of ATC facility under the FAA rules below. Training Squadron TEN (VT-10) gives its students a "Hollywood Script": every checklist and radio call of a T-6A training flight from Sherman Field, Naval Air Station Pensacola, in order. [1, pp. 1, 19–35] It shows the shape of a Navy sortie on the radio:

Copy ATIS, then get the clearance. ATIS on UHF 1, then clearance delivery on UHF 2: "Sherman Clearance, KATT 11, IFR, NPA 630, on request, ready to copy." The clearance is read back, and clearance delivery answers "KATT 11, readback correct." [1, pp. 19–20]
Tell the squadron. On the squadron base frequency (UHF 19): "KATT Base, KATT 11 taxi outbound, side number 000"; before takeoff, "KATT Base, KATT 11 going flying." [1, pp. 20, 25]
Ground, then tower. "Sherman Ground, KATT 11, taxi, information (ATIS letter)"; later, on UHF 4, "Sherman Tower, KATT 11, takeoff IFR." The takeoff readback carries the runway and ends "switching": "KATT 11, cleared for takeoff Runway 7 right, switching." [1, pp. 21, 25]
Departure and the working area. Check in climbing with the altitude you are passing and the altitude you are climbing to. Departure clears the flight to its working area, a military operations area (MOA), with "frequency change approved"; the MOA common frequency that follows is a safety-of-flight frequency used by departure, so there is no check-in. [1, pp. 27–29]
Come home on course rules. Cancel IFR when done in the area, copy ATIS, then "Pensacola Approach, KATT 11, 3500, information Bravo, request course rules." Approach hands the aircraft to tower at the entry point: "contact Sherman Tower Button 4." [1, pp. 30–32]
Break, land, and check back in. "Sherman Tower, KATT 11, Point Golf for the break"; "numbers 7 right"; tower: "right break approved". In the pattern, the position call ends with "gear, stop", and tower clears the aircraft to land. Stay with tower until clear of the runway, taxi back with ground, and finish on base: "KATT Base, KATT 11 in and up." [1, pp. 32–35]

Notice the readbacks: the script puts the call sign first ("KATT 11, cleared to land 7 Right"). The AIM asks for the call sign in every readback and its examples put it at either end, so both satisfy the FAA rule. [1, p. 34] [6, para 4-4-7]

Figure 4 — A Navy training sortie, call by call

Step through the calls. The drawing shows where the aircraft is on its sortie and which preset channel is up; the text gives the call, the reply and the readback.

Interactive figure unavailable. The calls in order: ATIS (UHF 1); Sherman Clearance (UHF 2); KATT Base (UHF 19), taxi outbound; Sherman Ground (UHF 3), taxi with the ATIS letter; KATT Base, going flying; Sherman Tower (UHF 4), takeoff IFR; Pensacola Departure (UHF 6), passing for 3000; cleared to the MOA, then MOA Common (UHF 16) with no check-in; Pensacola Approach on VHF 5, cancel IFR; Pensacola Approach (UHF 6), request course rules; Point Golf in sight, contact Sherman Tower Button 4; Sherman Tower, Point Golf for the break, numbers, break approved, gear, stop, cleared to land; Sherman Ground (UHF 3), taxi to the line; KATT Base, in and up.

The calls are VT-10's script for one T-6A sortie, lightly abridged; call sign, channels and places are the script's. Other squadrons, bases and aircraft use their own frequencies, entry points and calls. Profile heights are not to scale.

Making contact

An initial call has up to five parts, in this order: [6, para 4-2-3]

The name of the facility you are calling.
Your full aircraft identification, as filed in the flight plan.
Your position, when you are on the airport surface.
The type of message to follow, or your request if it is short.
"Over", if required.

The Navy script's calls follow the same order: "Sherman Ground, KATT 11, taxi, information (ATIS letter)" is facility, identification and request, with the ATIS code at the end. [1, p. 21] The AIM's examples are "New York Radio, Mooney Three One One Echo" and "Columbia Ground, Cessna Three One Six Zero Foxtrot, south ramp, I-F-R Memphis". After contact is established, use the same format, combining the call-up and the message in one transmission. Acknowledge every call-up or clearance unless told otherwise, and acknowledge a frequency change: "United Two Twenty-Two on one three four point five". Change to the new frequency as soon as possible unless told to change at a time, fix or altitude. [6, para 4-2-3] If the airport has automatic terminal information service (ATIS), say you have it on initial contact, using its code word: "have information Sierra". [6, para 4-1-13]

Figure 5 — Build the initial call

Select the pieces in the order you would say them.

Interactive figure unavailable. Order: facility, full identification, position on the airport surface, request. For example: "Columbia Ground, Cessna Three One Six Zero Foxtrot, south ramp, I-F-R Memphis."

The first two situations are from the VT-10 script; the third and fourth are the AIM's examples; the last is constructed. The script's ground call has no position element; away from home field, add your position on the airport surface as the AIM asks.

Words that do the work

A few procedure words carry precise meanings. Using the right one saves a transmission; using the wrong one can mislead. Roger means only that you received the whole transmission: it must not answer a yes-or-no question. [7, ROGER]

Roger: I have received all of your last transmission. It should not be used to answer a question requiring a yes or a no answer.
Wilco: I have received your message, understand it, and will comply with it.
Affirmative: Yes.
Negative: “No,” or “permission not granted,” or “that is not correct.”
Unable: Indicates inability to comply with a specific instruction, request, or clearance.
Say again: Used to request a repeat of the last transmission. Usually specifies transmission or portion thereof not understood or received.
I say again: The message will be repeated.
Stand by: The controller or pilot must pause for a few seconds, usually to attend to other duties of a higher priority. Also means to wait, as in “stand by for clearance.” The caller should reestablish contact if a delay is lengthy. “Stand by” is not an approval or denial.
Read back: Repeat my message back to me.
Verify: Request confirmation of information; e.g., “verify assigned altitude.”
Acknowledge: Let me know that you have received and understood this message.
Advise intentions: Tell me what you plan to do.
Immediately: Used by ATC or pilots when such action compliance is required to avoid an imminent situation.
Negative contact: Used by pilots to inform ATC that previously issued traffic is not in sight, which may be followed by a request for help avoiding it; or that they were unable to contact ATC on a particular frequency.
Words twice: As a request: “Communication is difficult. Please say every phrase twice.” As information: “Since communications are difficult, every phrase in this message will be spoken twice.”
Speak slower: Used in verbal communications as a request to reduce speech rate.
Over: My transmission is ended; I expect a response.
Out: The conversation is ended and no response is expected.

Definitions from the Pilot/Controller Glossary. [7, entries as listed]

Quiz: which word?

Acknowledgement and readback

Include the aircraft identification in every readback and acknowledgement. Read back the parts of ATC clearances and instructions that contain altitude assignments, vectors or runway assignments, as a means of mutual verification, and read altitudes, altitude restrictions and vectors back in the order they were given. Do not read back charted procedures unless the controller specifically states them. An initial readback of a taxi, departure or landing clearance should include the runway. [6, para 4-4-7] The AIM's examples: "Climbing to Flight Level three three zero, United Twelve" and "November Five Charlie Tango, roger, cleared to land runway nine left". [6, para 4-4-7] On an instrument flight rules (IFR) flight, make a written record of your clearance. [6, para 4-4-7]

Figure 6 — Read back the clearance

The controller's transmission is split into its parts. Select every part you must read back, then check.

Interactive figure unavailable. For "KATT 11, wind 060 at 8, Runway 7 right, cleared for takeoff, switch to Departure", read back the runway with your call sign: "KATT 11, cleared for takeoff Runway 7 right, switching."

The checker requires the parts AIM 4-4-7 lists: identification, altitude assignments and restrictions, vectors, and runway assignments. Reading back more is not marked wrong, but is shown. The first two instructions and their readbacks are from the VT-10 script; the third and fifth are adapted from the AIM's examples; the others are constructed.

Flight check-ins and frequency changes

A formation talks to ATC with one voice, its lead, and uses a separate tactical frequency between its own aircraft. One US Navy training squadron's formation supplement, VT-6's, sets out the pattern. Lead checks the flight in on the briefed tactical frequency on the ground, and once the flight is up on that frequency, neither aircraft switches off it for any reason. [2, p. 2] Radio changes are of three kinds: pre-briefed automatic switches, ATC-directed changes and lead-directed changes. Switches and check-ins are never made on an ATC, area common or common traffic advisory frequency, to keep traffic off saturated frequencies. If unsure of the correct frequency, use plain, concise language on the tactical frequency to get well. [2, p. 2]

The flight's tactical call sign ("Angry" in the supplement's examples) addresses the whole flight; each aircraft answers with its position in the flight. [2, pp. 2–3] Before taxi, lead calls "Angry, check Victor" and the wingman answers with its call sign and the ATIS code, or "Two, standby (X) mikes" if not ready. [2, p. 3] To leave the working area, lead calls "Angry, push UHF TAC" on the VHF tactical frequency, then checks the flight in on the new frequency: lead "Angry", wingman "Angry 1-2". A push to a frequency that becomes the working frequency, such as a VHF airfield frequency, has no check-in. [2, p. 10]

Figure 7 — Check-in and push, call by call

Interactive figure unavailable. Calls in order: on VHF TAC, "Angry, check Victor" – "Angry 1-2, with (ATIS code)"; later, "Angry, push UHF TAC"; both switch; on UHF TAC, "Angry" – "Angry 1-2".

One squadron's training example, simplified to the calls cited. Unit procedures, frequencies and call signs differ.

If a wingman loses its radio in formation, it gets lead's attention and signals by hand: patting the oxygen mask means it cannot talk, patting the ear of the helmet means it cannot hear, each followed by a thumbs-down. [2, p. 6]

Brevity and training-rule calls

Tactical calls use brevity words: short code words with fixed meanings, published jointly by the Army, Marine Corps, Navy and Air Force (ATP 1-02.1, MCRP 3-30B.1, NTTP 6-02.1, AFTTP 3-2.5), so a pilot from any service means the same thing by them. [4, p. i] A selection, each linked to its entry in the brevity words glossary:

Knock-it-off: Cease all air combat maneuvers, attacks, activities or exercises (training use only). [4, p. 26]
Abort: Cease action, or terminate the attack before weapons release, the event or the mission. [4, p. 2]
Blind: No visual contact with a friendly aircraft, ship or ground position. Opposite of visual. [4, p. 5]
No joy: Aircrew does not have visual contact with the target or bandit. Opposite of tally. [4, p. 31]
Padlocked: Aircrew cannot take their eyes off an aircraft, ground target or surface position without risk of losing tally or visual. [4, p. 32]
Joker: A fuel state above bingo at which separation, bugout or event termination should begin. [4, p. 25]
Bingo: The prebriefed fuel state needed for recovery. [4, p. 5]
Push: Switch to the designated frequency; no acknowledgment required. [4, p. 35]
Fence in / fence out: Set cockpit switches as appropriate before entering or exiting the combat area. [4, p. 18]
Buster: Fly at maximum continuous speed. [4, p. 7]
Popeye: Flying in clouds or an area of reduced visibility. [4, p. 34]
Pigeons: Bearing (magnetic) and range (nautical miles) to home plate. [4, p. 33]
Bogey: A contact whose identity is unknown. [4, p. 6]
Bandit: Positively identified as an enemy in accordance with theater ID criteria. [4, p. 4]

Air combat training adds a small set of calls whose job is safety: they stop, start and deconflict an engagement, and every player must know them before the first set. Each service's training rules set them; the examples here come from the Navy's T-45 basic fighter maneuvering (BFM) instruction, CNATRA P-1289. The training rules "shall be strictly observed", and they start with 500 feet of separation between all aircraft at all times. [3, pp. 3-1–3-2]

Knock it off: Stop the engagement. Anyone may call it; every player echoes it. An aircraft rocking its wings means the same. [3, p. 3-3]
Terminate: Temporarily stop the training for administrative reasons; lead restarts it. [3, p. 5-11]
Fight’s on: The engagement starts. Lead counts “3, 2, 1, fight’s on” and the wingman echoes it. [3, p. 5-14]
Blind: I cannot see my wingman anywhere. Said with your call sign, then turn away from the predicted collision bearing. [3, p. 3-3]
No joy: I cannot see the threat aircraft my wingman described. [3, p. 3-3]

"Knock it off" ends each set as well as any unsafe one: the instructor (dual) or bandit (solo) calls it at the end of every set, and both aircraft acknowledge. [3, p. 2-4] Passing head-on, the pass is called so both pilots go the same way: "high", "low", "right-to-right" or "left-to-left". [3, p. 3-4] The maneuvers themselves are in the BFM module.

Quiz: which training call?

Distress and urgency

Distress communications have absolute priority over all others; urgency communications come next. A distress call begins with MAYDAY, preferably said three times; an urgency call uses PAN-PAN in the same way. [6, para 6-3-1] Make the first call on the frequency in use, and do not change frequency or ground station unless absolutely necessary. [6, paras 6-3-1, 6-3-2] Transmit as many of these items as you need, preferably in this order: [6, para 6-3-2]

MAYDAY, MAYDAY, MAYDAY (or PAN-PAN ×3 for urgency)
Name of station addressed
Aircraft identification and type
Nature of distress or urgency
Weather
Pilot’s intentions and request
Present position and heading (or, if lost, last known position, time and heading since)
Altitude or flight level
Fuel remaining in minutes
Number of people on board
Any other useful information

While you are in radio contact, keep the assigned transponder code unless ATC tells you otherwise. If you cannot immediately reach an ATC facility, squawk code 7700 with altitude reporting (Mode C). [6, para 6-3-2]

Transponder codes

A transponder answers radar with a four-digit code. Unless ATC assigns one, a visual flight rules (VFR) aircraft squawks 1200. Three codes are special: 7500 is the hijack code, 7600 signals two-way radio failure, and 7700 signals an emergency; 7600 and 7700 trigger special indications in automated facilities. When changing codes routinely, avoid passing through 7500, 7600 or 7700: to change from 2700 to 7200, first select 2200, then 7200. [6, para 4-1-20]

Figure 8 — Change the code without an alarm

Each knob sets one digit. Every turn changes the code the transponder sends, so plan the order.

Interactive figure unavailable. From 2700 to 7200, change the second digit first (2200), then the first (7200); setting the first digit first would send 7700.

Each knob step is treated as one code sent. Real transponders differ in how and when a new code takes effect.

When the radio fails

At a towered airport

Arriving with the receiver inoperative, remain outside or above the Class D surface area until you have determined the direction and flow of traffic, then advise the tower of your aircraft type, position, altitude and intention to land, and request light signals. About 3 to 5 miles out, advise your position and join the traffic pattern, watching the tower for light signals. With the transmitter inoperative, monitor the tower frequency, and acknowledge tower transmissions or light signals by rocking your wings in daylight, or by blinking the landing or navigation lights at night. [6, para 4-2-13]

Airport traffic control tower light gun signals [6, para 4-3-13]
Signal	Aircraft on the ground	Aircraft in flight
Steady green	Cleared for takeoff	Cleared to land
Flashing green	Cleared for taxi	Return for landing (to be followed by steady green at the proper time)
Steady red	STOP	Give way to other aircraft and continue circling
Flashing red	Taxi clear of the runway in use	Airport unsafe, do not land
Flashing white	Return to starting point on airport	Not applicable
Alternating red and green	Exercise extreme caution	Exercise extreme caution

Figure 9 — Read the light gun

You are In flight On the ground

Interactive figure unavailable. Use the table above: for example, a flashing green signal to an aircraft in flight means return for landing, to be followed by steady green at the proper time.

With reduced motion set, flashing signals are shown as a dashed ring instead of blinking.

In instrument conditions

If two-way radio communication fails in VFR conditions, or VFR conditions are met after the failure, continue the flight under VFR and land as soon as practicable. In IFR conditions, fly the route and altitude below. [6, para 6-4-1] Squawk 7600, and remember that you may not be in radar coverage. [6, para 6-4-2]

Route, the first of these that applies: the route assigned in the last ATC clearance received; if being radar vectored, direct from the point of radio failure to the fix, route or airway specified in the vector clearance; without an assigned route, the route ATC has advised may be expected in a further clearance; otherwise, the route filed in the flight plan.
Altitude, for the route segment being flown, the highest of: the altitude or flight level assigned in the last ATC clearance received; the minimum altitude for IFR operations; and the altitude or flight level ATC has advised may be expected in a further clearance, once you reach the time or fix at which ATC said to expect it.
Leaving the clearance limit. If the limit is a fix from which an approach begins, start descent or descent and approach as close as possible to the expect-further-clearance time if you received one; if not, as close as possible to the estimated time of arrival from the filed or amended estimated time en route. If the limit is not an approach fix, leave it at the expect-further-clearance time if you received one, or on arrival if not, and proceed to a fix from which an approach begins; then start descent or descent and approach as close as possible to the estimated time of arrival calculated from the filed or amended estimated time en route.

All three rules: [6, para 6-4-1]

Figure 10 — Lost communications: route and altitude

When the radio failed Being radar vectored Route assigned Told to expect a route

Last assigned altitude Expected altitude

Interactive figure unavailable. With a route assigned, fly it. Assigned 5,000 ft, segment minimums 3,000, 7,000, 4,000 and 2,000 ft, and 9,000 ft expected from the third segment: fly 5,000, 7,000, 9,000 and 9,000 ft.

Illustrative segments and minimum altitudes. The expected altitude applies from the third segment, standing in for "expect 9,000 ten minutes after the fix"; set it to zero for no expected altitude. In the AIM, an expected altitude counts once you reach the time or place ATC said to expect it.

Check your understanding

You lose sight of your wingman during an engagement. What do you say and do?

"(Call sign) blind", and turn away from the predicted collision bearing. "No joy" is for a threat aircraft you cannot see, not your wingman.

Approach tells you "contact Sherman Tower Button 4". What is Button 4?

A preset radio channel, here channel 4, which the squadron's channel card sets to Sherman Tower.

Approach asks "Can you accept a visual approach?" and you can. Is "Roger" the answer?

No. Roger only says you received the transmission and must not answer a yes-or-no question. Say "Affirmative" with your call sign.

How do you say 17,500 ft and 18,500 ft?

"One seven thousand five hundred". At and above 18,000 ft it becomes a flight level: "flight level one eight five".

You are told "turn right heading zero niner zero, descend and maintain three thousand, altimeter two niner niner two". What must you read back?

The heading and the altitude, in that order, with your call sign. The AIM's readback list does not include the altimeter setting.

You need to go from 1700 to 7100. Which knob first?

The second digit: 1700 → 1100 → 7100. Setting the first digit first would send 7700.

Your radio fails in cloud while you are being vectored. Which route?

Direct from the point of failure to the fix, route or airway in the vector clearance.

A steady red light from the tower while you are in the pattern?

Give way to other aircraft and continue circling.

Where do you make a MAYDAY call?

On the frequency in use first; 121.5 or 243.0 if needed. Do not change frequency unless absolutely necessary.

Your fuel reaches the prebriefed state at which you must head home. What do you call?

"Bingo". "Joker" is the earlier, higher state at which you start to wind the event down.

Anyone in the flight sees a safety problem during training maneuvers. What is the call, and what does it do?

"Knock-it-off": everyone stops maneuvering. It is a training call, common to all four services' brevity list.

Sources and applicability

Military sources

[1] Training Squadron TEN (VT-10), "T-6A Checklist Study Guide ('Hollywood Script')", enclosure (1) to TRARONTENNOTE 3710, May 2022. Read the script (cnatra.navy.mil). Inspected 25 October 2026: radio calls pp. 19–35. A naval flight officer training squadron's script for one T-6A sortie from NAS Pensacola, used as the worked example of Navy training radio work; no distribution statement appears in the extracted text.

[2] Training Squadron SIX (VT-6), Formation Supplement (FORMSUP), June 2022. Read the supplement (cnatra.navy.mil). Inspected 25 October 2026: radio procedures pp. 2–3, NORDO signals p. 6, frequency changes p. 10. A single training squadron's formation supplement.

[3] Naval Air Training Command, CNATRA P-1289 (Rev. 01-16), Flight Training Instruction, Basic Fighter Maneuvering (1v1), Section Engaged Maneuvering (2v1), T-45. Revision 3 dated 7 January 2016, Change 1 dated 3 March 2021; cleared for public release. Read the instruction (cnatra.navy.mil). Inspected 25 October 2026: pp. 2-4, 3-1–3-4, 5-11, 5-14.

[4] Army, Marine Corps, Navy and Air Force, ATP 1-02.1 / MCRP 3-30B.1 / NTTP 6-02.1 / AFTTP 3-2.5, Brevity: Multi-Service Tactics, Techniques, and Procedures for Multi-Service Brevity Codes, 25 April 2025. Approved for public release; distribution unlimited. PDF (marines.mil). Inspected 25 October 2026: front matter and entries A to S; the text extractor did not reach entries after S.

[5] Joint Base San Antonio, "Midair Collision Avoidance (MACA) Handbook". PDF (jbsa.mil). Inspected 25 October 2026: p. 2. An Air Force base's guide for civil pilots.

Supplementary: FAA sources

[6] Federal Aviation Administration, Aeronautical Information Manual (AIM), current edition as published online. Inspected 25 October 2026 on faa.gov: chapter 4, section 2, Radio Communications Phraseology and Techniques (paras 4-2-1 to 4-2-14); chapter 4, section 4, ATC Clearances (para 4-4-7); chapter 6, section 3, Distress and Urgency Procedures (paras 6-3-1, 6-3-2); chapter 6, section 4, Two-way Radio Communications Failure (paras 6-4-1, 6-4-2); chapter 4, section 1, Services Available to Pilots (paras 4-1-13, 4-1-20); chapter 4, section 3, Airport Operations (para 4-3-13, light gun signals).

[7] Federal Aviation Administration, Pilot/Controller Glossary (P/CG), current edition as published online. Inspected 25 October 2026 on faa.gov, entries: R (Roger, Read back), W (Wilco, Words twice), A (Affirmative, Acknowledge, Advise intentions), N (Negative, Negative contact), S (Say again, Stand by, Speak slower), U (Unable, UHF), V (Verify, VHF), I (I say again, Immediately), O (Over, Out).

Page-specific excerpts are recorded in the repository review evidence: radio procedures evidence.

Figures 1–10 are original drawings and constructed examples, not reproductions of any publication's figures. Call signs, frequencies and timings in constructed examples are invented.

Applicability: written for US military pilots of all services. The brevity words [4] are joint across the Army, Marine Corps, Navy and Air Force. The sortie, formation and training-rule examples are from Naval Air Training Command scripts and instructions [1–3] and show one squadron's practice, not a service-wide standard; your flight manual and your service's, wing's and squadron's procedures govern. The FAA AIM and Pilot/Controller Glossary [6, 7] are the US civil rules that military aircraft of every service also follow in the National Airspace System; they are cited here as the supplementary rule set behind the military calls. ICAO and other national procedures differ in detail. This revision is Drafted pending independent source-backed review.