Guessing it might be easier for game's program to do a "check list" for preset quests, rather than checking for every achievement there is, per second...
So for some achievements would be a "Quest!"
Example:
1) Before a flight, we click "Quest."
2) click the achievement we want to attempt from the list.
3) take off in the required plane and do the stuff in order...
4) get the achievement for the quest.
Yeah yeah though, I too, for one, would probably rather have a new He-177 than a bunch of achievements... fun though!