AIM - RAC 4.5 4

Mandatory Frequency

Transport Canada has designated a Mandatory Frequency (MF) for use at selected
uncontrolled aerodromes, or aerodromes that are uncontrolled between certain hours.
Aircraft operating within the area in which the MF is applicable (MF area), on the
ground or in the air, shall be equipped with a functioning radio capable of maintaining
two-way communication. Reporting procedures shall be followed, as specified in
CARs 602.97 to 602.103 inclusive.

An MF area will be established at an aerodrome if the traffic volume and mix of aircraft
traffic at that aerodrome is such that there would be a safety benefit derived from
implementing MF procedures. There may or may not be a ground station in operation at
the aerodrome for which the MF area has been established. When a ground station is in
operation, for example, an FSS, an RCO through which RAAS is provided, a CARS, or
an Approach UNICOM, then all aircraft reports that are required for operating within,
and prior to entering an MF area, shall be directed to the ground station. However,
when the ground station is not in operation, then all aircraft reports that are required for
operating within and prior to entering an MF area shall be broadcast. The MF will
normally be the frequency of the ground station which provides the air traffic advisory
services for the aerodrome. For the aerodromes with an MF, the specific frequency,
distance and altitude within which MF procedures apply will be published in the CFS.

Examples     1. MF—rdo 122.2 5 NM 3100 ASL

                     2. MF—UNICOM (AAU) ltd hrs O/T tfc 122.75 5 NM 3100 ASL

AIP - RAC 4.5 6

Use of MF and ATF

When operating in accordance with VFR, or in accordance with IFR but in VMC,
pilots have sole responsibility for seeing and avoiding other aircraft. Aural and visual
alertness are required to enhance safety of flight in the vicinity of uncontrolled
aerodromes. At uncontrolled aerodromes for which an MF or ATF has been
designated, certain reports shall be made by all radio-equipped aircraft.

NOTE:        Pilots operating VFR en route in uncontrolled airspace or VFR on an airway
                    should continuously monitor 126.7 MHz when not communicating on the
                    MF or ATF.

Reports on either the MF or ATF have three formats; either:

(a) a directed transmission made to a ground station;

(b) a directed transmission made to a vehicle operator on the ATF; or

(c) a broadcast transmission that is not directed to any particular receiving station.

Whenever the CFS indicates that reports are to be made to a ground station, the initial
transmission should be made to the station. To assist in reducing frequency congestion,
pilots are encouraged to use the phrase HAVE NUMBERS on the initial call to a
ground station (arrival or departure) to indicate that they have received runway, wind
and altimeter information from the previous aerodrome advisory. When operating
outside an MF area and when frequency congestion prevents pilots from making their
mandatory calls, it is their responsibility to remain clear of the MF area until contact
can be established with the FSS. If operating inside an MF area, the pilot should
continue as stated in previous radio transmissions.

Pilot:       CHARLO RADIO, BELLANCA FOXTROT X-RAY YANKEE ZULU
                6 SOUTHWEST 3 500 VFR. INBOUND LANDING WITH THE
                NUMBERS.

Should there be no acknowledgement of a directed transmission to a ground station or
a vehicle operator, reports shall be made in the broadcast format unless the ground
station or vehicle operator subsequently establishes two-way contact, in which case
pilots shall resume communicating by directed transmission.

Examples:

Directed:        CHARLO RADIO, THIS IS PIPER FOXTROT X-RAY YANKEE ZULU
                        BEACON INBOUND LANDING RUNWAY 18.
                        or,
                        CHARLO VEHICLES, THIS IS PIPER FOXTROT X-RAY YANKEE
                        ZULU…

Broadcast:      CHARLO TRAFFIC, THIS IS PIPER FOXTROT X-RAY YANKEE
                        ZULU…