there is no hours restriction on engineers as there is for crew
.. which reminds me of an anecdote from 1982, when our Sqn very nearly (but not quite) went south.
At an Execs, SEngO said that he would put his troops on a "war shift pattern" of 12 on 12 off; whereupon one of the flying Flt Cdrs pointed out that the aircrew were "normally" on (up to) a 14/10.
Oh how we laughed...