By JC Audet

Canada has a large number of uncontrolled aerodromes, where no control tower operates. Either the aerodrome does not have a control tower or the Control Tower operates during specified periods. For instance, the CFS might indicate that the tower is closed from 2300 until 0700 daily. The aerodrome then becomes an uncontrolled aerodrome. Depending on the density and mix of traffic at an uncontrolled aerodrome, TCCA may designate a Mandatory Frequency (MF) or an Aerodrome Traffic Frequency (ATF).

Regulations mandate that an aircraft operating within a Mandatory (MF) area shall be equipped with a functioning two-way radio and reporting procedures shall be followed as specified in CARs 602.97 to 602.103 inclusive. This clearly means that when one flies within an MF area, one shall communicate (transmit and listen) on the designated frequency as listed in the CFS. If a ground station is in operation (FSS, Unicom, RCO, etc) within the MF area, transmissions shall be addressed to the station; otherwise, the pilot will broadcast blind. For aerodromes with an MF, the specific frequency, distance and altitude within which MF procedures apply will be published in the CFS.

Examples:

MF—rdo 122.2 5 NM 3100 ASL 

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

Some aerodromes have a designated Aerodrome Traffic Frequency (ATF) based again on the mix and density of traffic. The ATF is established to ensure that all radio-equipped aircraft operating on the ground or within the area are listening on a common frequency and following common reporting procedures. The ATF will normally be the frequency of the UNICOM where one exists or 123.2 MHz where a UNICOM does not exist. Personnel providing UNICOM service and trained vehicle operators who possess a valid radiotelephone license and are authorized to do so, can communicate with pilots using two-way communication on the ATF and provide information such as:

(a) position of vehicles on the maneuvering area;

(b) position of other aircraft on the maneuvering area; and

(c) runway condition, if known.

The specific frequency, distance and altitude within which use of the ATF is required will be published in the CFS. Note that it is legal to operate NORDO in an ATF.

Example:

ATF – tfc 123.2 5 NM 5500 ASL 

An ATF may also be designated for areas other than an aerodrome, when VFR traffic activity is high and an ATF could enhance flight safety.

The pilot-in-command always carries the full responsibility for using proper communications and for maintaining adequate vigilance to ensure safe operations. Always carry a current CFS and ascertain the designated area (MF or ATF) applicable to your portion of flight.