WHITEHORSE, YT – 18 December 2019 – Coping with winter flying weather.
This fall has brought some unusual weather to the Yukon and this has caused more flight delays and cancellations than we normally experience. In view of this, I thought that our travelers might be interested in learning more about how airlines are able to cope with poor weather at some of the airports we fly to.
In order for pilots to safely and legally land an aircraft on a runway they must, by a specified point in their landing approach, be able to see enough of the runway to land and stop safely. The required distance could be as little as a few feet above the ground and as little as one eighth of a mile visibility or it could be as much as several thousand feet above the ground and several miles visibility. The exact cloud ceiling and visibility requirements are determined by equipment that is available for each runway (usually provided by Nav Canada) at a particular airport and by the equipment installed in the aircraft. To illustrate, here are some examples of how poor weather might impact our flights to Whitehorse (YXY), Vancouver (YVR), and Dawson City (YDA), three airports that Air North, Yukon’s Airline flies to and from regularly.
For Whitehorse, with winds from the north, calm winds, or light winds from the south, aircraft are authorized to land from the south with cloud ceilings as low as 200 feet above the ground. When the winds are blowing strongly from the south, landings must be made from the north, and the airport equipment available for landings from the north permits landings when cloud ceilings are at least 388 feet above the ground if the airline has the required equipment in the aircraft or 725 feet above the ground if the airline does not have the required equipment installed. While all Air North aircraft have the equipment required for lower ceiling approaches from the north, it should be noted that the clouds have to be almost twice as high when we must land from the north.
For Vancouver, all four main runways are equipped to permit landings with ceilings right down to the ground and visibilities as low as 1/8 mile provided that certain conditions are met by the airline and the airport. These conditions include specialized aircraft equipment and crew training and specialized runway lighting and back-up power generation capability. Air North is authorized to land at YVR with cloud ceilings as low as 200 feet above ground.
For Dawson City, despite the capability of the aircraft to permit landings at ceilings as low as 200 feet in YXY and YVR, the terrain surrounding YDA dictates that the lowest cloud ceiling for any of the instrument approaches is 1666 feet, which is more than four times the required cloud ceiling at either YXY or YVR.
As an airline, it is our job to get you to your destination safely and on time. As a northern airline we have invested in aircraft and aircraft equipment that allow us to do the best job possible at the airports we fly to and from most frequently. Hopefully the foregoing discussion will help our travelers to better understand why weather conditions sometimes dictate delays or cancellations.
Joseph Sparling, President,
Air North, Yukon’s Airline