I was looking at the Designated Airspace Handbook tonight and noticed something peculiar.
The DAH is the legal document that describes Canada’s airspace. It defines all airspace from control zones, special use areas, classes A through F as well as low level airways.
I noticed this oddity for LF/MF airway A-2 and A-15:
A2
Calgary, AB NDB \ to
Red Deer, AB NDB \ to
Edmonton, AB NDB \ to
Whitecourt, AB NDB \ to
Grande Prairie, AB NDB \ to
Dawson Creek, BC NDB \ to
Fort St. John, BC NDB \ to
Fort Nelson, BC NDB \ to
Liard River, BC NDB \ to
Watson Lake, YT NDB \ to
Whitehorse, YT NDB
. . .
Beaver Creek, YT NDB \ to
Nabesna, AK USA NDB
A15
Banne, BC Intxn \ to
Nichols, AK USA NDB
. . .
Beaver Creek, YT NDB \ to
Nabesna, AK USA NDB
You will notice that the last segments of each airway overlap each other (Beaver Creek NDB to Nabesna NDB). How does that work? Can the same airway have TWO designations? Is this an error?
It happens with Victor airways too, and I’m sure you’ve seen the surface highways do the same. It allows pilots and controllers to easily specify complex routes and tell them apart even though some may share sequential navaids.
Happens a lot, even around here, look at toronto LO chart, more than 1/2 of the airways of YYZ are double, or in one case triple designated.