4.2 Aircraft Communications

Aviation relies on dedicated radio frequencies. In Canada, civil voice communications take place on the Very High Frequency (VHF) AM band, ranging from 118.10 MHz to 136.00 MHz. Pilots should be familiar with the common voice frequencies, the licensing required to transmit, standard phraseology, and emergency signals.

1. Licensing and Language Rules

Radio Operator Requirements

Two-way radio transmissions on aviation frequencies in Canada are regulated by Innovation, Science and Economic Development Canada (ISED).

To legally transmit on aviation frequencies, you must hold a Restricted Operator Certificate with Aeronautical Qualification (ROC-A).

• Validity: Once obtained, the ROC-A is valid for life.
• Testing: The proficiency test is simple compared to obtaining an amateur radio license and is available through ISED-accredited examiners (including many commercial flight schools).
• Study Material: ISED publishes the official RIC-21 study guide for this exam. It is highly recommended that you read it as a supplement to this guide.

Note

By law, aviation frequencies are strictly reserved for flight safety and operational messages—casual air-to-air chatting is prohibited. Amateur radios allow pilots to legally chat, share weather reports, and organize landing retrieves. (Note: Legally transmitting on a ham radio requires a separate Amateur Radio Operator Certificate).

2. Frequencies of Special Interest

Memorize these specific frequencies for the exam:

• 121.50 MHz: International aircraft emergency frequency (some aircraft monitor this in case they can assist).
• 122.75 MHz: The air-to-air advisory frequency for aircraft that need to coordinate directly with each other rather than with ATC.
• 123.20 MHz: The standard frequency used by all unregistered aerodromes (and registered ones without a specific assigned frequency). If you can’t see an aerodrome frequency on the VNC, then the frequency is 123.20 MHz.
• 123.40 MHz: The frequency allocated to gliders/sailplanes. Since hang gliders are gliders, we are allowed to use this frequency.
• 126.70 MHz: The frequency aircraft should continuously monitor in uncontrolled airspace when not near an aerodrome. Pilots broadcast their location and intentions here so that other pilots in the vicinity can be made aware of any potential conflict. In areas where FIC/FSS frequencies have been introduced, this frequency is used less.

Note

It is sometimes very difficult to figure out what frequency a passing aircraft will be on. While 126.70 MHz is the standard en-route frequency, passing aircraft often switch to an aerodrome’s frequency before the typical five mile radius, or monitor a TCA frequency if they are close to its boundaries. If you operate close to an aerodrome, it is highly recommended to use that aerodrome’s frequency so local powered pilots are aware of you. Radios that permit being live on one frequency while monitoring another can be very useful in these situations.

3. Standard Radio Usage

Radio communications have been standardized to reduce ambiguity. This section provides only a basic overview of radio communication procedures consistent with what can be expected on the HAGAR examination.

Call Signs

For registered aircraft, the call sign is the registration number. For a hang glider, the call sign is HANG GLIDER followed by the phonetic form of the pilot’s initials.

Example: A pilot named Andre Nadeau would use the call sign HANG GLIDER ALPHA NOVEMBER.

The International Civil Aviation Organization (ICAO) Phonetic Alphabet

You must know the international phonetic alphabet for radio clarity.

Letter	Word	Letter	Word	Letter	Word
A	Alpha	J	Juliette	S	Sierra
B	Bravo	K	Kilo	T	Tango
C	Charlie	L	Lima	U	Uniform
D	Delta	M	Mike	V	Victor
E	Echo	N	November	W	Whiskey
F	Foxtrot	O	Oscar	X	X-ray
G	Golf	P	Papa	Y	Yankee
H	Hotel	Q	Quebec	Z	Zulu
I	India	R	Romeo

Basic call structure and etiquette

• Keep transmissions short and relevant (location, intentions, altitude or height AGL where useful).
• If transmitting a position when gliding near an aerodrome or traffic, include distance and bearing from a known point (e.g., “two miles west of [aerodrome name]”), altitude (AGL or ASL as appropriate), and intentions (landing, joining pattern, etc.).
• Avoid unnecessary transmissions on emergency or aerodrome frequencies.

Declaring an Emergency

Emergency conditions are classified by the degree of danger being experienced.

1. Distress (MAYDAY)

A situation of grave and imminent danger requiring immediate assistance.

• Call: State the signal MAYDAY three times at the beginning of the transmission.
• Example: “MAYDAY, MAYDAY, MAYDAY. This is Hang Glider Alpha November, two miles from shore of mont St Pierre, 1000 ft, heading towards shore, imminent ditching for lack of altitude.”

2. Urgency (PAN PAN)

A condition concerning the safety of an aircraft, vehicle, or person that requires assistance as soon as possible, but is not immediately life-threatening.

• Call: State the signal PAN PAN three times at the beginning of the transmission.
• Example: “PAN PAN, PAN PAN, PAN PAN. This is Hang Glider Alpha November, (message).“

4. Technical Notes on Radios

Keep these points in mind so you understand why airband equipment differs from ham gear.

Different Frequencies

• Airband: Operates on VHF frequencies between 108.000 MHz and 136.975 MHz (voice communications generally happen between 118.000 and 136.975).
• Amateur: The closest amateur VHF band is the “2-meter band,” which operates between 144.000 MHz and 148.000 MHz in North America.

Different Modulation (AM vs. FM)

Airband radios use AM (Amplitude Modulation). They do this because if two pilots try to talk over each other on AM, the signals mix together and create a squeal, but both voices can usually still be heard.

Standard VHF Ham radios use FM (Frequency Modulation). In FM, if two people talk at once, the stronger signal completely blocks out the weaker one (known as the “capture effect”), which would be dangerous in aviation.

Hardware and Legal Limitations

Many modern ham radios have “wideband receivers” that allow you to listen to the airband in AM mode. However, they are physically, electronically, and legally “locked” from transmitting on those frequencies. Transmitting on aviation bands with non-certified equipment is a massive federal offense due to the safety-of-life nature of air traffic control.