Based on the CFS on Foreflight, it says the while the Tower is open, Saskatoon radio transfers from Radio to Tower, then FSS takes care of "The Pas/Flin Flon" RAAS sites. Then, there's a half hour period before The Pass/Flin Flon RAAS close up, and Saskatoon Radio opens when the tower closes. I'm pretty certain that the tower is operated solely by VFR trained controllers, and there are rotations between day shift and night shift for the FSS staff.
I'm just curious to know how the airport operates.
