Building a timeline (without giving it a time... so just... line) for Blade becoming an aerial firefighter and befriending Mayday.
Blade got trained at CalFire under Helitack 301, a Bell UH-1H Huey. (Blade either have a different call sign number or none at all beforehand. Let's go with "30" if he was given a call sign number.)
Once Blade got certified, his mentor pass the call sign number 301 to him since they already planned on retiring from duty (if what I read up is right, the Bell UH-1H became Helitack 908 at McClellan Air Tanker Base, so irl helo not really retiring).
So when CalFire starts deploying the Firehawks, there is no Firehawk 301 since Blade already carries the number. (if what I searched up is right, CalFire updated their helo numbering system recently. So as of last year(??) CalFire Firehawks are 600-612 iirc. Doesn't really impact this bullet point that much tho.)
Before being deployed to Piston Peak, Blade was stationed at Mendocino for some time. This is when/where he and Mayday got acquainted and become friends.
Quite later, Mayday would move to Minnesota and be stationed at Propwash Junction while Blade moved to Oregon and stationed at Piston Peak.
They keep in touch, like monthly call or something. Since Propwash Junction don't usually went up in flames, Mayday usually calls to talk about interesting things around town. While Blade, during fire season, more often than not calls to talk about what a bad month he's having since stuff burns down on the regular there (once Cad became superintendent, it's always been very-bad-no-good-very-VERY-crappy months).