ROC-A Study Guide

The official study guide published by Innovation, Science and Economic Development Canada (ISED) that outlines the essential knowledge, regulations, and operating procedures needed to pass the ROC-A exam and legally operate aviation radios in Canada.

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Communication Priorities

When you’re transmitting on aviation radio, some messages have higher priority than others. The order is simple:

1. Distress calls (Mayday – life-threatening situations)
2. Urgency calls (Pan-Pan – important but not immediately life-threatening)
3. Radio direction-finding messages
4. Flight safety messages (traffic advisories, navigational info, etc.)
5. Weather messages
6. Routine operational messages that support regular flight operations
7. Authorized UN-related messages
8. Government messages with requested priority
9. Telecommunication service messages (technical or administrative)
10. All other normal aeronautical communications

In practice, for a pilot: Distress and urgency always come first. Everything else fits below those based on safety and operational importance.

Privacy of Communications

Anything you hear on the aviation radio is considered private, even though it’s broadcast openly. You’re not allowed to share the details of any communication you hear unless:

• you’re the intended recipient,
• you’re passing it along to someone authorized to receive it,
• or it’s necessary for safety (e.g., distress or emergency messages).

Distress, urgency, general safety messages, and broadcasts to “ALL STATIONS” (like weather warnings) are exceptions—those can be freely repeated when needed.

Breaking radio-privacy rules can lead to serious fines or penalties, so the guiding rule is simple:

If it’s not your message, don’t repeat it.

Control of Communications

When you’re talking on the radio, someone is always in charge of how the communication flows. Here’s the simple rule:

On the ground → the ground station controls the communication.
In the air (aircraft-to-aircraft) → the aircraft being called controls the communication.

What this means in practice:

• Ground stations decide which frequency to use and when you should talk.
• Aircraft must follow the ground station’s instructions on frequency changes, timing, and when to start or stop transmitting.
• The only exception is during distress or urgency calls, where the station making the emergency call takes control.

Inside the aircraft, the radio is ultimately under the control of the pilot (or another person the pilot designates).

When aircraft talk to each other, the aircraft being called decides whether to accept the frequency the calling aircraft suggests.

• If it agrees, it simply acknowledges and switches.
• If it doesn’t agree, it tells the calling aircraft which frequency to use instead.

Simple Examples
1. Ground station calling an aircraft - Ground station has control.

OTTAWA RADIO:  “Piper C-FXQQ, this is Ottawa Radio. Go ahead on tower frequency 122.1. Over.”

2. Aircraft calling a ground station - Ground station still has control.

Piper C-FXQQ:  “Ottawa Radio, this is Piper C-FXQQ on frequency 122.1. Over.”

3. Aircraft calling another aircraft - The aircraft being called has control.

Piper C-FXQQ:  “Cessna C-FXQT, this is Piper C-FXQQ on frequency 119.7. Over.”

If the called aircraft wants to change frequencies:

Cessna C-FXQT:  “Piper C-FXQQ, this is C-FXQT. Change to SAR frequency 123.6. Out.”

For all example above - the full Phonetic Alphabet is to be used in practice.  Using the last example above, it would be:

PIPER CHARLIE FOXTROT X-RAY QUEBEC QUEBEC
THIS IS
CESSNA CHARLIE FOXTROT X-RAY QUEBEC TANGO
CHANGE TO SEARCH AND RESCUE FREQUENCY ONE TWO THREE DECIMAL SIX
OUT

Superfluous Communications and Interference

Aviation radio is for important, safety-related, and operational messages only. Anything unnecessary, casual, or off-topic shouldn’t be transmitted.

You must not use:

• unnecessary chatter,
• jokes or casual conversation,
• profane or inappropriate language.

Using the radio for anything outside safety and flight operations, or interfering with another station’s communication, can lead to serious penalties.

Never interrupt another transmission unless you have a higher-priority message such as:

• Mayday (distress)
• Pan-Pan (urgency)
• another officially recognized priority call

In short: keep transmissions professional, necessary, and clear.

False Distress Signals

You must never intentionally transmit a false distress call of any kind.

Knowingly sending a fake “Mayday,” “Pan-Pan,” or any other false emergency message is a serious offence and can result in major fines or criminal penalties.

The rule is simple:

Only declare an emergency if an actual emergency exists.

Speech Transmission Techniques

Clear radio communication depends on how you speak as much as what you say. Radios can distort certain consonants and make similar-sounding words blend together, so good technique is essential.

When transmitting, speak clearly, calmly, and at a steady pace. Avoid shouting, rushing, or letting your words run together. The goal is to sound natural, but crisp and easy to understand.

Keep these key points in mind:

• Speed: Speak at a normal, steady rate—not too fast and not too slow. Remember, the person listening may need to write your message down.
• Rhythm: Use the natural rhythm of normal conversation. Pronounce each word carefully and avoid slurring or clipping sounds.
• Clarity: Keep your voice relaxed, articulate consonants clearly, and avoid exaggerated emphasis or dramatic tone.

Think of it this way: If your message is easy to understand the first time, everyone’s job becomes easier and safer.

Time and Date

Aviation uses the 24-hour clock for radio calls. Time is always sent as four digits:

• The first two digits = hour after midnight
• The last two digits = minutes past the hour

Examples:

• 12:45 a.m → 0045
• 12:00 noon → 1200
• 11:45 p.m → 2345
• 12:00 midnight → 0000 or 2400
• 1:30 a.m → 0130
• 1:45 p.m → 1345
• 4:30 p.m → 1630

To avoid confusion with time zones, aviation normally uses UTC (also called Zulu time). When flights or operations happen only within a single time zone, local time can be used.

If you need to send both date and time, use six digits:

• First two = day of the month
• Next four = time (24-hour format)
• Add a letter for the time zone if required (e.g., Z, E for EST, P for PST)

Examples:

• 16th day at 12:00 noon EST → 161200 E
• 24th day at 2:45 a.m PST → 240245 P

ITU Phonetic Alphabet

The ITU phonetic alphabet is used worldwide to make radio communication clearer—especially when spelling call signs, names, or any words that could be misunderstood. Every pilot must know it well enough to use it instantly, especially in poor radio conditions.

You use the phonetic alphabet whenever:

• spelling aircraft registration
• reading back clearances
• transmitting unfamiliar names or words
• communication quality is weak

Phonetic Alphabet

Letter	Word	Pronounced
A	Alfa	AL-FAH
B	Bravo	BRAH-VOH
C	Charlie	CHAR-LEE / SHAR-LEE
D	Delta	DELL-TAH
E	Echo	ECK-OH
F	Foxtrot	FOKS-TROT
G	Golf	GOLF
H	Hotel	HOH-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 / OO-NEE-FORM
V	Victor	VIK-TAH
W	Whiskey	WISS-KEY
X	X-ray	ECKS-RAY
Y	Yankee	YANG-KEY
Z	Zulu	ZOO-LOO

 

Numbers (How to Say Them on the Radio)

Number	Said As
0	ZE-RO
1	WUN
2	TOO
3	TREE
4	FOW-ER
5	FIFE
6	SIX
7	SEV-EN
8	AIT
9	NIN-ER

 

Additional terms:

• Decimal → DAY-SEE-MAL
• Hundred → HUN-DRED
• Thousand → TOW-SAND

Transmission of Numbers

When transmitting numbers on the radio, say each digit separately, unless the number is a whole thousand.

General Rules

• Say each digit individually
  • 10 → “one zero”
  • 75 → “seven five”
  • 100 → “one zero zero”
  • 5800 → “five eight zero zero”
• For whole thousands, say the digits, then “thousand”
  • 11,000 → “one one thousand”
• If there's a decimal, say “decimal”
  • 121.5 → “one two one decimal five” 

Money (if ever transmitted)

Say the units in the order written.

• $17.25 → “dollars one seven decimal two five”
• $0.75 → “decimal seven five”

Altitude and Flight Levels

• Altitudes are said in thousands and hundreds
  • 2700 → “two thousand seven hundred”
• Flight levels use separate digits
  • FL265 → “flight level two six five”

Aircraft Types, Wind, and Clouds

Some aviation numbers are spoken as groups, not digit-by-digit:

• Flight 320 → “flight three twenty”
• DC10 → “D C ten”
• 34BKN → “thirty four hundred broken”
• Wind 270/10 → “wind two seven zero degrees one zero knots”

Time (UTC / Zulu)

• 0920Z → “zero niner two zero zulu”
• 09 → “nine minutes past the hour”

Headings

Always spoken as three digits:

• 005° → “heading zero zero five”
• 350° → “heading three five zero”

Headings are:

• Magnetic in the Southern Domestic Airspace
• True in the Northern Domestic Airspace

(Don’t worry—flight training will explain this in detail.)

Aerodrome Elevation

Say the elevation in feet, prefixed with “field elevation”:

• 150 → “field elevation one five zero”
• 3500 → “field elevation three thousand five zero zero”

Procedural Words and Phrases

Aviation radio communication uses standard words and phrases so everyone understands each other clearly and consistently. While there isn’t a set phrase for every situation, slang or casual expressions must never be used on aviation frequencies.

Avoid phrases like:

• “OK”
• “Repeat” (use “say again” instead)
• “Ten-four”
• “Over and out”
• “Breaker breaker”
• “Come in please”

Using non-standard language can cause confusion and delay, especially in busy or emergency situations.

The rule is simple:
Use approved aviation phraseology whenever possible, and keep your transmissions clear, professional, and standardized.

Call Signs

A call sign is how an aircraft is identified on the radio. It must be used when first making contact and again when ending a transmission so everyone knows exactly who is speaking.

Call signs should always be spoken using the phonetic alphabet to avoid confusion.

For most pilots, the aircraft’s call sign is the same as its registration markings, which are assigned to the aircraft by Transport Canada.

Simple rule:
Use your call sign at the start and end of radio calls, and always say it phonetically.

Canadian Air Carrier Call Signs

Canadian commercial operators use their company name as the call sign, followed by either the flight number or the last three characters of the aircraft registration.

Example: "Air Canada one four niner"

This helps clearly identify commercial flights and avoids confusion with private or training aircraft.

Canadian Private Aircraft Call Signs

Canadian private aircraft use the manufacturer’s name or aircraft type, followed by the last four letters of the registration.

The call sign is always spoken using the phonetic alphabet.

Example: "Cessna one eight two Golf Foxtrot Alfa Charlie"

This format clearly identifies the aircraft type and avoids confusion on busy frequencies.

Aeronautical Ground Stations

Ground stations identify themselves by location, followed by a word that describes what they do. This tells pilots who they are talking to and what type of service to expect.

You’ll hear the station name first, then its function.

Common examples:

• Brantford UNICOM — airport advisory - someone on the ground providing advisories
• Inuvik Radio — remote flight information or advisory service
• Ottawa Centre — area control centre
• Toronto Ground — surface movement (taxi) control
• Ottawa Information — flight information service
• Edmonton Delivery — clearance delivery
• Ottawa Arrival — approach control (arrivals)
• Winnipeg Departure — approach control (departures)
• Montreal Precision — precision approach radar
• Eskimo Tower — community aerodrome radio station
• Radio — private aeronautical station
• Dispatch — company dispatch
• Hinton Traffic - MULTICOM - no control tower, no UNICOM, and no flight service station

Memory Tip

• ATC → You request and receive clearances
• MF / UNICOM / RADIO → You report and receive advisories
• MULTICOM → You broadcast to other pilots
• Dispatch → Company coordination only

Simple rule:
Listen to the station name and function — it tells you who’s in charge and what kind of help they provide.

See Radio Usage Examples

Radiotelephone Calling Procedure

In most cases, the pilot is responsible for initiating radio contact when entering the service area of a ground station. However, a ground station may also call an aircraft if needed.

When multiple aircraft try to call a ground station at the same time, the ground station decides who speaks first, based on the priority of each message. Higher-priority calls (such as distress or urgency) will always be handled first.

Simple takeaway:
Pilots usually make the first call, but the ground station controls the order of transmissions based on message priority.

Calling

Before you transmit, listen first. Make sure the frequency is clear so you don’t interrupt another conversation. If someone else is already talking, wait for a break before making your call.

The only time you may interrupt another transmission is for distress, urgency, or safety messages.

When making a call, always use this order:

Station being called → “THIS IS” → your call sign

Example: “Calgary Tower, THIS IS Helicopter Golf Foxtrot Alfa Charlie…”

Simple rule:
Listen first, don’t step on others, and always say who you’re calling before who you are.

Single-Station Call

When calling one specific station, use the following order. In normal conditions, say each part once.

Call order:

1. Station you’re calling
2. “THIS IS”
3. Your call sign
4. Your frequency
5. “OVER”

Example: “Toronto Tower, THIS IS Cessna One Eight Five Foxtrot Alfa Delta Tango, on frequency one one eight decimal seven, OVER.”

Key tips:

• Repeat call signs only if radio conditions are poor
• Speak clearly and calmly
• Keep it short and professional

All Stations General Call

An “ALL STATIONS” call is used when you want to reach any station or aircraft within range, rather than one specific station.

Use the same structure as a single-station call, but replace the station name with “ALL STATIONS.” In normal conditions, saying it once is enough.

Call order:

1. “ALL STATIONS”
2. “THIS IS”
3. Your call sign
4. Your frequency (if required)
5. “OVER”

Example: “All stations, THIS IS Toronto Air Radio, OVER.”

Tip:
Use “ALL STATIONS” only when necessary, such as for safety broadcasts or when you’re unsure which station is listening.

Multiple-Station Call

A multiple-station call is used when you need to contact more than one specific station at the same time.

When making the call:

• Say the call signs of the stations you want to reach, in any order
• Follow with “THIS IS”
• Then say your call sign
• End with “OVER”

In normal conditions, each call sign is said once.

Example: “Cessna Foxtrot November India Lima, Piper Foxtrot X-Ray Quebec Quebec, Piper Golf Lima Lima Delta, THIS IS Toronto Tower, OVER.”

Replying to a multiple-station call:
Stations should reply in the order they were called, unless the controller or situation requires otherwise.

Key Takeaways:
Multiple-station calls are uncommon for training pilots, but when you hear one, wait your turn and respond in order.

Replying to Radio Calls

When you hear a call directed to your station, reply as soon as possible.

You have two basic responses:

• “GO AHEAD” — you’re ready to receive the message
• “STAND BY” — you’re not ready; include how long the delay will be

Examples:

• “Piper Foxtrot X-Ray Quebec Quebec, THIS IS Toronto Tower, GO AHEAD.”
• “Piper Foxtrot X-Ray Quebec Quebec, THIS IS Toronto Tower, STAND BY two minutes.”

If You’re Not Sure the Call Is for You

• If you hear a call but aren’t sure it’s meant for you, don’t reply until it’s repeated and clearly understood.
• If you’re unsure who is calling, reply immediately using “STATION CALLING” and ask them to repeat.

Example: “Station calling Cessna Foxtrot November Juliett India, SAY AGAIN, OVER.”

Ending a Conversation

To end a radio exchange, finish with “OUT.”
This tells the other station that no reply is expected.

Example: “Toronto Tower, THIS IS Piper Foxtrot X-Ray Quebec Quebec, received runway clearance, OUT.”

Takeaways:

• Reply promptly
• Use GO AHEAD or STAND BY
• Ask for clarification if unsure
• Use OUT only when the conversation is finished

Corrections and Repetitions

Correcting a Mistake

If you make a mistake while transmitting, don’t start over. Simply say “CORRECTION”, then repeat the last correct word, followed by the correct information.

Examples:

• “Over Ottawa at two seven — CORRECTION — two eight.”
• “Proceed to Dock Four — CORRECTION — Dock Five.”

Asking for a Repeat

If you didn’t hear or understand something:

• Use SAY AGAIN to ask for the message to be repeated.

You can be specific to save time:

• “SAY AGAIN ALL BEFORE …” (everything before a word)
• “SAY AGAIN … TO …” (between two words)
• “SAY AGAIN ALL AFTER …” (everything after a word)

Examples:

• “Vancouver Radio, THIS IS Stinson Foxtrot Alfa Bravo Charlie, SAY AGAIN ALL BEFORE ‘hangar’, OVER.”
• “Winnipeg Tower, THIS IS Cessna Foxtrot Papa Delta Quebec, SAY AGAIN ‘altitude’ TO ‘descend’, OVER.”
• “Montreal Centre, THIS IS Cessna Foxtrot X-Ray Quebec Tango, SAY AGAIN ALL AFTER ‘flight plan’, OVER.”

Takeaways:

• Use CORRECTION immediately if you misspeak
• Use SAY AGAIN when something isn’t clear
• Be specific when possible to keep radio traffic efficient

Message Handling Procedures

Before you transmit:

• Think first — know what you’re going to say
• Listen briefly — make sure the frequency is clear
• Speak clearly and concisely, using standard phraseology when possible

Most radio exchanges follow the same simple four-step flow:

• Call-up — who you’re calling and who you are
• Reply — the other station tells you to proceed
• Message — the actual information you want to pass
• Acknowledgment — confirmation or closing

Example Flow

1. Call-up (Aircraft):
   “Schefferville Radio, THIS IS Piper Foxtrot Alfa Bravo Charlie, OVER.”
2. Reply (Ground):
   “Piper Foxtrot Alfa Bravo Charlie, THIS IS Schefferville Radio, GO AHEAD, OVER.”
3. Message (Aircraft):
   “Schefferville Radio, THIS IS Piper Foxtrot Alfa Bravo Charlie, four miles at one thousand, landing Schefferville, OVER.”
4. Reply (Ground):
   “Piper Foxtrot Alfa Bravo Charlie, THIS IS Schefferville Radio, roger. Wind one six zero at one five, altimeter two niner niner seven, OVER.”
5. Acknowledgment (Aircraft):
   “Schefferville Radio, THIS IS Piper Foxtrot Alfa Bravo Charlie, roger.”

Shortened Calls (Once Communication Is Established)

After initial contact:

• You may omit “THIS IS” and “OVER”
• The station being called may be abbreviated
• Keep transmissions short and clear

Example: “Schefferville Radio Bravo Charlie, confirm right on Sierra.”

Takeaways:

• Plan → Listen → Transmit
• Follow the four-step flow
• Shorten calls once the conversation is established

Signal (Radio) Checks

A signal check is used to confirm that your radio is working and readable. Keep these checks short and professional.

How to Request a Signal Check

1. Choose an appropriate frequency that won’t interfere with normal operations.
2. Call another aircraft or a ground station and request a signal (or radio) check.
3. Include your call sign in the transmission.
4. Keep the check under 10 seconds.

Standard request format: “Signal check one two three four five, how do you read me? OVER.”

Readability Scale (Used for Replies)

When replying to a signal check, use this scale:

1. Bad – unreadable
2. Poor – readable now and then
3. Fair – readable but with difficulty
4. Good – readable
5. Excellent – perfectly readable

Types of Communication Checks

• Signal check — done while airborne
• Preflight check — done before departure
• Maintenance check — done by ground maintenance

Example Exchange

Request: “Watson Lake Radio, THIS IS Cessna Foxtrot Alfa Bravo Charlie, request signal check.”

Reply: “Cessna Foxtrot Alfa Bravo Charlie, THIS IS Watson Lake Radio, reading you strength five, OVER.”

Takeaways:

• Use signal checks only when needed
• Keep them short
• Always include your call sign
• Use the readability scale when replying

Emergency Conditions

In aviation, emergencies are divided into two levels, based on how serious the situation is.

Distress

A distress condition means the aircraft or people on board are in grave and immediate danger and require help right now.

• Life-threatening situation
• Immediate assistance needed
• Declared using “MAYDAY”

Urgency

An urgency condition means there is a serious safety concern, but it is not immediately life-threatening.

• Aircraft or occupant safety is affected
• Assistance may be needed, but not immediately
• Declared using “PAN-PAN”

Takeaways: 

• MAYDAY = immediate danger
• PAN-PAN = serious concern, not yet life-threatening

Distress Communications

When an aircraft is in distress, standard emergency radio procedures should be used whenever possible. However, in a real emergency, nothing takes priority over getting help.

If needed, a station in distress may use any available means to:

• attract attention
• communicate its position
• obtain assistance

Takeaways:
Follow proper procedures when you can — but in a true emergency, do whatever is necessary to be heard and get help.

Frequencies to Use in a Distress Situation

When declaring a distress call, use the frequency you are already on first.

If you can’t establish contact, immediately try:

• the aeronautical emergency frequency – 121.5 MHz, or
• any other frequency available that might reach another aircraft or ground station.

Takeaway:
Start with the frequency you’re using. If that doesn’t work, go to 121.5 or any frequency that gets help.

Distress Signal (MAYDAY)

In aviation radio communications, the spoken distress signal is “MAYDAY.”
It must be spoken at the very start of your first distress transmission.

Using MAYDAY tells everyone listening that:

• You are in grave and immediate danger and need help right now, or
• You are aware of another aircraft or vehicle that is in grave and immediate danger and needs immediate assistance

Once MAYDAY is declared, your transmission has absolute priority over all other radio traffic.

Takeaways:

• MAYDAY = immediate, life-threatening emergency
• Say it first, clearly, and without hesitation
• Use it only when the situation truly warrants it

Priority of Distress

A distress call has absolute priority over all other radio transmissions.

When a MAYDAY is heard:

• All other stations must stop transmitting immediately
• Everyone should continue listening on that frequency
• No transmission should interfere with the distress traffic

Takeaway:
If you hear a MAYDAY, stop talking and listen — the frequency now belongs to the aircraft in distress.

Control of Distress Traffic

Control of distress traffic normally belongs to the aircraft in distress or the station relaying the distress message.

If needed, control may be handed over to another station, such as an aeronautical ground station, that can better coordinate with ATC and search-and-rescue (SAR) services.

Takeaway:
The aircraft in trouble controls the emergency—unless it passes that responsibility to another station to manage the response.

Distress Call

A distress call is used only with the authority of the pilot in command and clearly identifies the aircraft in trouble.

The distress call format is fixed and should be spoken before anything else:

1. “MAYDAY” — spoken three times
2. “THIS IS”
3. Your aircraft call sign — spoken three times

Example:

“MAYDAY, MAYDAY, MAYDAY
THIS IS
Piper Foxtrot X-Ray Charlie Charlie
Piper Foxtrot X-Ray Charlie Charlie
Piper Foxtrot X-Ray Charlie Charlie”

Important Rules to Remember

• A distress call is not addressed to any specific station
• Do not wait for a reply before sending your distress message
• The call simply announces the emergency and clears the frequency

Takeaway:
The distress call gets attention. The message comes next.

Distress Message

The distress message is sent immediately after the MAYDAY call.
Its purpose is to tell rescuers what’s wrong, where you are, and what you plan to do.

Say as much of the following as you can, clearly and calmly:

1. MAYDAY (if not already said)
2. Your call sign (once)
3. What happened and what help you need
4. Your intentions (what you’re going to do)
5. Your position (location, altitude, heading, airspeed)
6. Persons on board and any injuries
7. Any other helpful information
8. Your call sign (again)

Example Distress Message

“MAYDAY
Piper Foxtrot X-Ray Quebec Quebec
Struck by lightning, ditching aircraft
Position twenty miles east of Winnipeg
Altitude one thousand five hundred feet
Airspeed one two five knots
Heading two seven zero degrees
One person on board
Piper Foxtrot X-Ray Quebec Quebec”

Important Notes:

• If you send the message immediately after the MAYDAY call, you may omit repeating “MAYDAY” and your call sign at the start
• Say only what you can — partial information is better than none
• Stay calm and speak clearly

Key Takeaway:

What happened → Where you are → What you’ll do → Who’s on board

Repeating a Distress Message

If you declare a distress message and no one responds, you should repeat the message at intervals until:

• you receive a reply, or
• it’s no longer possible to continue transmitting.

Leave enough time between repeats for other stations to answer.

If another station hears a distress message that hasn’t been acknowledged and can’t help directly, it must:

• try to alert other stations that may be able to help, and
• notify search and rescue (SAR) as soon as possible.

Key Takeaways:

• Repeat your distress call if no one answers
• Pause between repeats to allow replies
• Other stations have a duty to help get assistance, even if they can’t respond directly

Actions by an Aircraft in Distress

When an aircraft is in grave and immediate danger, the pilot in command should take the following actions, in order, if possible:

1. Transmit the distress call (MAYDAY)
2. Transmit the distress message (what’s wrong, where you are, what you plan to do)
3. Listen for acknowledgment
4. Continue exchanging distress traffic as needed
5. Activate emergency equipment (such as the ELT) when appropriate

Takeaway:

Call → Message → Listen → Communicate → Activate ELT

Actions by Stations Not in Distress

An aircraft or station not in distress may need to help relay or support a distress situation when:

• the aircraft in distress cannot transmit its own message, or
• the pilot believes additional help is needed, or
• a distress message is heard but not acknowledged by anyone.

In these cases, another station may relay the distress message to help ensure assistance is provided.

Important Listening Rule

If you hear a distress message and the aircraft is not nearby, wait briefly before responding.
This allows stations closer to the emergency to reply first, which may be more effective.

Key Takeaways:

• You may need to relay a MAYDAY if no one responds
• Give nearby stations a chance before replying
• Helping doesn’t always mean flying to the scene — passing the message matters

Actions by Other Stations Hearing a Distress Message

If you hear a distress (MAYDAY) message, you must take the following actions:

1. Continue listening on the same frequency and, if possible, monitor emergency frequencies as well.
2. Notify stations that can help, such as those with radar, direction-finding, or SAR coordination, unless you know this has already been done.
3. Stop all transmissions that could interfere with the distress traffic.

Key Takeaways:

• Listen continuously
• Help pass the message to those who can assist
• Do not transmit unless it helps the emergency

Distress Traffic

Distress traffic includes all radio transmissions made after the initial MAYDAY call that relate to helping the aircraft in trouble.

Key rules to remember:

• Every distress transmission should begin with “MAYDAY” spoken once
  • This alerts anyone who may have just tuned in that an emergency is in progress
• Any station that hears distress traffic and cannot help directly must:
  • continue listening, and
  • follow the situation until it’s clear that assistance is being provided
• No other stations may transmit on the distress frequency unless:
  • they are directly involved in the emergency, or
  • they are helping relay information

Normal radio traffic may only resume after an official message states the distress has been cancelled.

Key Takeaways:

• After MAYDAY, everything is distress traffic
• Start each distress transmission with “MAYDAY”
• If you’re not involved, stay silent and listen
• Do not transmit until the distress is officially cancelled

Acknowledging a Distress Message

When a distress (MAYDAY) message is received and you are the station acknowledging it, use a standard response format so everyone clearly understands the emergency is being handled.

The acknowledgment should include:

1. “MAYDAY”
2. Call sign of the aircraft in distress — spoken three times
3. “THIS IS”
4. Your call sign — spoken three times
5. “RECEIVED MAYDAY”

Example Acknowledgment

“MAYDAY
Piper Foxtrot X-Ray Quebec Quebec
Piper Foxtrot X-Ray Quebec Quebec
Piper Foxtrot X-Ray Quebec Quebec
THIS IS
Winnipeg Tower
Winnipeg Tower
Winnipeg Tower
RECEIVED MAYDAY”

Key Takeaways:

• Acknowledge clearly and exactly
• Repeat call signs three times
• This confirms the distress call has been heard and assistance is being coordinated

Actions After Acknowledging a Distress Message

When a station acknowledges a MAYDAY, it has specific responsibilities to manage the emergency.

That station must:

1. Acknowledge the distress immediately
2. Take control of the distress communications, or clearly state if control is being transferred to another station
3. Ensure all critical information is passed quickly to:
   1. Air Traffic Services (ATS), and
   2. the aircraft’s operating agency or representative
4. Continue monitoring the distress frequency, and any other frequency the aircraft may be using
5. Warn other stations to keep non-emergency traffic off the distress frequency
6. Stop any transmissions that could interfere with distress traffic

Takeaway:

Once a distress is acknowledged, one station manages the emergency and keeps the frequency clear until help is underway.

Relay of a Distress Message

If you hear a distress call and the aircraft in trouble cannot transmit, or no one has acknowledged the MAYDAY, another station may relay the distress message.

The relay begins with a specific format so everyone knows it is second-hand emergency traffic.

MAYDAY RELAY Format

1. “MAYDAY RELAY” — spoken three times
2. “THIS IS”
3. Your call sign — spoken three times
4. “MAYDAY” — spoken once
5. Details of the aircraft in distress, including:
   1. call sign
   2. nature of the emergency
   3. position, altitude, heading, airspeed
   4. persons on board

Example MAYDAY RELAY

“MAYDAY RELAY, MAYDAY RELAY, MAYDAY RELAY
THIS IS
Cessna November Juliett India
Cessna November Juliett India
Cessna November Juliett India
MAYDAY
Piper Foxtrot X-Ray Quebec Quebec
Struck by lightning, ditching aircraft
Position twenty miles east of Winnipeg
Altitude one thousand five hundred feet
Airspeed one two five knots
Heading two seven zero degrees
One person on board
Piper Foxtrot X-Ray Quebec Quebec”

Key Takeaways:

• Use MAYDAY RELAY only when relaying someone else’s emergency
• Repeat only what you know — partial information is acceptable
• The goal is to get help involved quickly

Imposition of Silence

During a distress situation, the aircraft in distress or the station controlling the distress traffic can order radio silence to keep the frequency clear.

This can be directed at:

• one specific station, or
• all stations in the area.

When silence is imposed, all non-essential transmissions must stop immediately. Only stations involved in the distress traffic may transmit.

Key Phrases to Know

• “SEELONCE MAYDAY”
  Used by the aircraft in distress or the station controlling the emergency to order silence.
• “SEELONCE DISTRESS”
  Used by other nearby stations if it is essential to help protect the distress frequency.

Example: Silence Ordered on One Station

“Cessna Foxtrot November Juliett India,
THIS IS Piper Foxtrot X-Ray Quebec Quebec,
SEELONCE MAYDAY, OUT.”

Example: Silence Ordered on All Stations

“All stations, all stations, all stations,
THIS IS Cessna Foxtrot November Juliett India,
SEELONCE DISTRESS, OUT.”

Key Takeaways:

• SEELONCE = stop transmitting
• SEELONCE MAYDAY → ordered by the aircraft in distress or controlling station
• SEELONCE DISTRESS → used by other stations if necessary
• When silence is imposed: listen only

Cancellation of Distress

When an emergency is over and radio silence is no longer required, the station that controlled the distress traffic must inform everyone that normal radio use can resume.

This announcement is made on the distress frequency and is addressed to ALL STATIONS.

Distress Cancellation Format

The cancellation message includes:

1. “MAYDAY” (spoken once)
2. “HELLO ALL STATIONS” (spoken three times)
3. “THIS IS”
4. Call sign of the station making the cancellation
5. Time (UTC)
6. Call sign of the aircraft that was in distress
7. “SEELONCE FEENEE” (meaning distress traffic has ended)
8. “OUT”

Example Cancellation

“MAYDAY
HELLO ALL STATIONS, HELLO ALL STATIONS, HELLO ALL STATIONS
THIS IS Winnipeg Tower
Time one six three zero Zulu
Piper Foxtrot X-Ray Quebec Quebec
SEELONCE FEENEE
OUT”

Important Note

This cancellation message is mainly to tell other stations they may resume normal radio traffic.
Search and Rescue must still be contacted separately with details explaining why the distress was cancelled.

Key Takeaways:

• Only the controlling station cancels distress traffic
• SEELONCE FEENEE = distress traffic ended
• Normal radio use resumes only after cancellation is announced

Urgency Signal (PAN-PAN )

The urgency signal is used when there is a serious safety concern, but immediate assistance is not yet required.

It is sent only with the authority of the pilot in command and tells others that the message is important and needs priority, but it is not a MAYDAY.

How to Use PAN-PAN

• The urgency signal is “PAN-PAN” spoken three times
• It is spoken at the beginning of the first urgency transmission
• It may be addressed to:
  • ALL STATIONS, or
  • a specific station

When to Use PAN-PAN

Examples include:

• engine or system problems that are serious but under control
• low fuel with options still available
• medical issues that are not immediately life-threatening

Key Takeaways:

• PAN-PAN = urgent, but not life-threatening
• Say it three times at the start
• Use it before things become a MAYDAY

Priority of an Urgency Signal

An urgency signal (PAN-PAN) has priority over all normal radio traffic, but lower priority than a MAYDAY.

When you hear PAN-PAN:

• Stop transmitting and listen on that frequency
• Continue listening for at least three minutes
• Do not interfere with the urgency message that follows

If no urgency message is heard after that time, an aeronautical ground station should be notified if possible, and normal radio use may resume.

Important Clarifications

• Stations on other frequencies may continue normal operations unless the urgency message is addressed to ALL STATIONS
• PAN-PAN traffic deserves space and attention, but it does not shut down all aviation communications like a MAYDAY does

Key Takeaways:

• PAN-PAN = second-highest priority
• Listen carefully and avoid interference
• MAYDAY always overrides PAN-PAN

Frequencies to Use for an Urgency Call

When declaring an urgency (PAN-PAN) call:

• Use the frequency you are already on first
• If you can’t establish contact, switch to:
  • the aeronautical emergency frequency — 121.5 MHz, or
  • any other frequency available that might reach another aircraft or a ground station

Takeaway:

Start where you are. If no one answers, go to 121.5 or any frequency that gets attention.

Urgency Message

After declaring PAN-PAN, you must send an urgency message explaining what’s wrong and what you need.

If the message is addressed to ALL STATIONS and another aircraft or ground station acknowledges it, that station is responsible for passing the information to the appropriate authorities (ATC, airport operator, etc.).

Urgency Message Format

Include as much of the following as you can, clearly and calmly, in this order:

1. “PAN-PAN” — spoken three times
2. Station addressed or “ALL STATIONS” — spoken three times
3. “THIS IS”
4. Your aircraft call sign
5. Nature of the problem
6. Your intentions
7. Position, altitude, heading
8. Any other useful information

Example Urgency Message

“PAN-PAN, PAN-PAN, PAN-PAN
ALL STATIONS, ALL STATIONS, ALL STATIONS
THIS IS Cessna Foxtrot November Juliett India
Lost, request radar check
Position unknown
Airspeed one one two knots
Altitude one zero five zero feet
Cessna Foxtrot November Juliett India, OVER”

Example Reply

“PAN-PAN
Cessna Foxtrot November Juliett India
THIS IS Winnipeg Tower
Your position is twenty miles south of Winnipeg
Winnipeg Tower, standing by”

Key Takeaways:

• PAN-PAN first, then explain the problem
• Say what’s wrong, where you are, and what you plan to do
• If addressed to ALL STATIONS, someone else will help pass the message along

Cancellation of an Urgency Message

When an urgency situation is resolved and help is no longer needed, the station that sent the PAN-PAN must cancel it as soon as possible.

The cancellation is always addressed to ALL STATIONS so everyone knows normal radio operations can resume.

Urgency Cancellation Format

The cancellation message should include:

• “PAN-PAN”
• “ALL STATIONS” (spoken three times)
• “THIS IS”
• Your aircraft call sign
• A brief statement that the situation is resolved
• Your call sign again
• “OUT”

Example Cancellation

“PAN-PAN
ALL STATIONS, ALL STATIONS, ALL STATIONS
THIS IS Cessna Foxtrot November Juliett India
Cessna Foxtrot November Juliett India has been positioned twenty miles south of Winnipeg Airport and is proceeding normally
Cessna Foxtrot November Juliett India
OUT”

Key Takeaways:

• Cancel a PAN-PAN as soon as it’s no longer needed
• Always address the cancellation to ALL STATIONS
• Keep the message short and clear

 

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