13.2 Frequencies, MF/ATF & Emergency Calls

13.2 Frequencies, MF/ATF & Emergency Calls

Quick Answer: Learn what tower, ground, MF, ATF, and 121.5 MHz are for. Near many uncontrolled aerodromes, Mandatory Frequency and Aerodrome Traffic Frequency procedures create a shared traffic picture (CAR 602.97–602.103 themes). Recognize MAYDAY and PAN-PAN. Treat crew radios as imperfect RF systems (interference, shielding, range). Use radio when it truly supports safety—but written RPAS Flight Authorization (often via NAV Drone) remains the primary legal control path into controlled airspace, not a chat with tower.

Section 13.1 covered how to speak. This section covers where you speak, what emergency language means, and when radio is the tool versus when authorization and see-and-avoid carry the operation.

Common aeronautical frequency concepts

Canadian VFR pilots select frequencies from the Canada Flight Supplement (CFS), charts, and ATIS/published sources. Advanced RPAS pilots need the functional map:

121.5 MHz — emergency awareness

121.5 MHz is widely taught as the civil VHF emergency frequency. Crewed aircraft in distress or urgency may use it; many aircraft also monitor 121.5 when able. For Advanced RPAS exam purposes:

• Know that 121.5 is for emergency/urgency use, not routine Class D entry, not a substitute for NAV CANADA RPAS authorization, and not a place to practice phonetics.
• False or frivolous emergency transmissions are serious offences and destroy trust in the system.
• If you hear a real distress situation nearby, do not clog the frequency; keep your operation from becoming a second hazard (land or clear as appropriate).

Tower and ground in one mental model

At towered aerodromes, ground manages the apron/taxi story; tower manages the runway and airborne circuit/control zone story. RPAS Advanced candidates should recognize those roles so scenario questions about “who talks where” make sense—even though your RPAS entry into the controlled volume is gated by written authorization conditions, not by freelancing a tower request like a NORDO ultralight myth.

Mandatory Frequency (MF) and Aerodrome Traffic Frequency (ATF)

Why uncontrolled does not mean silent

Uncontrolled aerodromes lack an operating control tower providing ATC clearances, but they are often busy with training flights, aerial work, medevac helicopters, and itinerant traffic. Canada publishes MF and ATF arrangements so pilots share a common frequency and make position reports that build a traffic picture.

What Advanced RPAS pilots must internalize

1. Find the frequency in the CFS/chart products during site survey and pre-flight information gathering.
2. If you will operate in a way that participates in that radio environment, use a qualified operator, correct frequency, and standard reports (ID, position, altitude, intentions).
3. Monitor continuously while the requirement or safety case applies (listening-watch discipline from 13.1).
4. Understand that crewed aircraft may be joining downwind, on final, or transitioning near the field below 1,000 feet AGL—exactly where VLOS drones live.
5. NORDO crewed aircraft may still appear; radio is a powerful tool, not a guarantee that every target is talking.

Exam item pattern: “Near an MF area at an uncontrolled aerodrome, pilots should…” → monitor and broadcast on the published MF, not shut radios off, not invent 243.0 MHz as a routine civil aerodrome channel, and not wait until after landing to start caring about traffic information.

Vicinity operations and reporting awareness (CAR 602.97–602.103 themes)

The CAR 602.97–602.103 family (aerodrome traffic procedures / reporting themes in Part VI) exists so pilots operating to, from, or in the vicinity of aerodromes share predictable behaviour: circuit direction, reporting points, radio calls where required, and right-of-way integration with the visual circuit.

You are not expected to recite every subsection number on the Advanced written exam, but you are expected to understand the traffic-picture purpose:

• Aerodromes concentrate risk: many aircraft, low altitude, changing intentions.
• Reports and standard patterns reduce collision risk between crewed aircraft.
• RPAS Advanced operations near aerodromes inherit the same geometry of risk even when the legal tools differ (standoff distances, authorizations, VLOS).
• Listening to MF/ATF while staging a nearby job (when radio-equipped and authorized to monitor) can warn you of a medevac helicopter inbound long before you see it.

Link to earlier chapters: certified airport 5.6 km / 3 NM and heliport 1.9 km / 1 NM standoff rules, control-zone authorization, and site survey all interact with radio. Frequency knowledge without lateral planning is incomplete; lateral planning without frequency awareness is also incomplete.

Emergency radio calls: MAYDAY and PAN-PAN

Distress vs urgency

Recognition points for Advanced candidates

• Triple repetition of the signal word is the classic teaching form for voice distress/urgency.
• Distress has priority over urgency; urgency has priority over routine traffic.
• A complete distress message typically aims to deliver who, where, what, and what assistance is needed—so rescuers can act.
• You must never transmit a false MAYDAY/PAN-PAN. False signals waste rescue resources and are treated as serious violations.
• If your RPA flyaway creates a serious aviation hazard (for example toward a busy control zone), your notification path may include ATC/emergency services as taught in flight-operations emergencies—not a theatrical MAYDAY as a substitute for landing your controllable assets and calling the right agency clearly.

SECURITÉ (safety) awareness

Some training materials also discuss SECURITÉ for safety-related broadcasts (hazards, important safety information) at a lower priority than PAN-PAN. For the Advanced exam, prioritize solid MAYDAY vs PAN-PAN discrimination and the rule against false emergency traffic.

Crew member radios: terminology and reception performance

Advanced crews often carry:

• Aeronautical VHF handhelds or vehicle mounts (qualified use only)
• Crew coordination radios (business band, licensed systems, or other lawful short-range crew links—distinct from aeronautical band)
• C2 / video links on the RPAS itself (command-and-control, not ATC phraseology)

Reception performance factors

Radio check culture: when voice radio is part of the plan, confirm readability before you need it in a conflict. “How do you read?” / readability scales appear in ROC-A-style training; the operational point is simple—verify the path works.

Interference and shielding

Radio problems are not only “weak battery.” Site survey from earlier chapters already flagged EMI; apply it to crew voice radios and C2:

• Power lines, broadcast towers, radar, industrial EMI can raise noise floors.
• Metal structures, shipping containers, vehicle bodies shield and multipath signals.
• Dense urban canyons create dead zones on VHF just as they multipath GNSS.
• Other RPAS and event Wi-Fi congest the bands your C2 uses; aeronautical VHF can still be stepped on by poor discipline from other users.
• Shielding works both ways: a radio in a metal case or under a carbon stack may receive poorly; an antenna pressed to foil insulation may fail.

Mitigations: external antenna when appropriate, body position, test calls from the actual operating pad, backup battery, and a non-radio fallback (land, visual signals within the crew, abort criteria) if reception collapses.

When RPAS pilots need radio vs when NAV Drone authorization is the primary path

This is a high-yield Advanced distinction.

Written authorization first in controlled airspace

Operations in controlled airspace generally require RPAS Flight Authorization from NAV CANADA (commonly requested through NAV Drone) or the appropriate authority near military aerodromes. That written product sets:

• Lateral and vertical limits
• Time windows
• Coordination or conditions
• Any communication expectations tied to the authorization

Radio does not replace authorization. You cannot “call tower for a drone clearance” as a substitute for the RPAS authorization process. Practice-bank framing is explicit: understanding phraseology helps you interpret the manned traffic environment; it does not equip your drone with Mode C or grant Class C/D entry by itself.

When radio adds real safety value

When radio is not the primary control path

Decision checklist (say it in the crew brief)

1. Is any part of the volume controlled? → Authorization status green before arming.
2. Are we in/near an MF/ATF environment where voice participation is part of our plan? → ROC-A, frequency, watch, reports.
3. What is our action if radio fails or reception is unreadable?
4. What is our action if crewed traffic appears regardless of radio?
5. Emergency: who calls 911 / ATC / Transport Canada for flyaway or ground hazard (from flight-ops chapter)—and do we understand MAYDAY/PAN-PAN if we hear them?

Exam integration

Expect stems that mix frequency choice, emergency signal recognition, MF behaviour, and the authorization-versus-radio trap. Correct answers usually:

• Put 121.5 in the emergency box
• Put MF/ATF in the uncontrolled aerodrome traffic-picture box
• Put NAV Drone / written authorization in the controlled-airspace legality box
• Put see-and-avoid above any assumption that “everyone is on frequency”

Bottom line: Frequencies are tools for a shared sky. MF/ATF and vicinity reporting themes keep uncontrolled aerodromes predictable. MAYDAY and PAN-PAN mark true distress and urgency. Crew radios fail when interference, shielding, or poor setup win—so test them. And never confuse a clean radio call with the authorization that legally opens controlled airspace for RPAS.