1. From AIP RAC 4.5.6: "Pilots operating VFR enroute in uncontrolled airspace or VFR on an airway should continuously monitor 126.7 MHz when not communicating on the MF or the ATF."
  1. 126.7 MHz is the VFR enroute frequency, as well as a frequency available at most FSSs. You can use it to make position reports and hear where other aircraft in your vicinity are, and you can ask for weather and NOTAM information when you are in range of an FSS.
  2. 123.2 MHz is the frequency to use when landing at an aerodrome with no published frequency, such as a private strip, or when landing a float plane on a lake. Some aerodromes use 123.2 as a published frequency.
  3. 122.8 MHz is a very common UNICOM frequency for uncontrolled fields in the United States, and I believe it was once used as an air-to-air frequency in Canada.
  4. 122.2 MHz. is the frequency for Flight Watch in the United States. It's not quite the same as 126.7 in Canada, as pilots don't make position reports and can't change their flight plan on this frequency. It is only for weather and PIREPs.