Capt P B. .I think that Jackson VC was NOT a F/E (a rather new branch at that time), but a member of the longest operating aviation crew branch - Radio Operators... probably a W.Op/AG or, maybe, a Signaller.. .As regards third crew - certainly, but, as has been mooted here occasionally in the past, have a non-flying Aircraft Commander - much the safest option but neither politically nor professionally acceptable.... pity.