Think of it as Job Security? They wont fire you for fifteen whole years !! And you get to fly all sorts of hours for years for the cargo fleet and at 2/3 the salary of pilots who came in as F/O (and they are underpaid versus the competition too). But beats sitting in an office in Taipei making 1K/month flying a desk though ?
If you started at say 21, you come out 15 years later as a very experienced F/O at 36 ready to take on the world ! Sort of
