So with 3 crew, does the purser do the safety demo as well???? on our B737-800 we have a minimum compliment of 5 crew and 1 csm but in extreme circumstances we can do with 4 crew and 1 csm. what normally happens is there is CSM and number 2 do J/C, and 3 , 4, 5, 6 do Y/C service