avcafe
16th Oct 2017, 11:11
CAVOK term is not used in canada, why it is like that?
+TSRA
19th Oct 2017, 23:49
I quote from the TC AIM 2017-2 Effective October 12, 2017 to March 29, 2018:
1.4 USE OF TERM “CAVOk”
The term “CAVOK” (KAV-OH-KAY) may be used in air- ground communications when transmitting meteorological information to arriving aircraft.
CAVOK refers to the simultaneous occurrence of the following meteorological conditions at an airport:
(a) no cloud below 5 000 feet, or below the highest minimum sector altitude, whichever is higher, and no cumulonimbus;
(b) a visibility of 6 SM or more;
(c) no precipitation, thunderstorms, shallow fog, or low drifting snow.
This term, coupled with other elements of meteorological information, such as wind direction and speed, altimeter setting and pertinent remarks, will be used in transmissions directed to arriving aircraft and, where applicable, in the composition of ATlS messages. A pilot, on receipt of CAVOK, may request that detailed information be provided.
CAVOK does not apply to the provision of meteorological information to en route aircraft and, therefore, will not be used when such information is transmitted to aircraft engaged in that particular phase of flight.
Further, from another section of the same manual:
7.3 NATIONAL VARIATIONS
As with the aerodrome routine meteorological report (METAR) code, even though aerodrome forecast (TAF) is an international code, there are national variations. For example, “CAVOK” is not authorized for use in Canadian TAFs, while “RMK” is used, but is not part of the international code. See MET 1.1.8 for more information on differences from the International Civil Aviation Organization (ICAO) Annex 3.
There are numerous locations in Canada - Specifically, the Designated Mountainous Regions - where the phrase "no cloud below the highest minimum sector altitude" limits the use of CAVOK. Perhaps this is why you have not seen it as quite a few of our major airports (YVR, YYC, YUL, YHZ, YYT) are located within these areas.