Stated psychological type required was stable extrovert. 20/30 years ago (Cold War), RAF Doc of my acquaintance said most FJ types were (in his opinion) introverts when sober, extroverts when drunk, and borderline unstable always.
Job requirement was a preparedness (but not a desire) to drop a nuclear weapon on a Sov. primary school, daily* if necessary. This doesn't attract too many people who were otherwise considering accountancy.
(* not the same school, obviously. That would be a bit harsh...
Rather a waste of resources too.
n.b. school was assumed to have an HQ under it)
Adlib
Lonewolf - I think we should add never, EVER, giving up.