If you're here trying to do the Blue Dragonflight questline in order to get you Tarecgosa mount (standalone), but can't find the quest, here's what I did ...
I couldn't find Kalecgos at the Azure Archives, but a quest did finally pop up there (on my map) that said "Winterspring", which is one of the quests in the Blue Dragonflight series that eventually leads to the mount. Odd. However, no NPC there actually offered the Winterspring quest, it was simply phased out at the Archives.
I kept backtracking and trying to find any pre-reqs that would phase me in to see Kalecgos, and eventually happened upon a quest in Ohn'ahran Plains at 71-80 (Forkriver Crossing), called "Into the Azure". I followed the storyline quests (the exclamation points with dark brown shield icons), which only took about 5 mins, and it took me to just outside the archives to Kalecgos. I did a few more very short quests, (trying not to give spoilers) where he's questioned "where is the rest of the Blue Dragonflight?" and he says they're scattered. Sounded a lot like the intro to the moutn questline to me!
I checked the map and in Valdrakken (NOT in the Veiled Ossuary), there was a quest named "Keeper of the Ossuary". In Val, I found Kalecgos atop the tower in the Seat of the Aspects with the Keeper quest where you're asked to meet Senegos at the Veiled Ossuary with the quest "Keeper of the Ossuary" which led directly to "On the Trail Again". Now you're on the right track to do the Blue Dragonflight quest!
Hope this helps somebody!