Well, in the late '70s we always wore SD caps when going to the jet - even on normal trips! Mine used to live wedged between the AVS hose and the cockpit floor on the RHS of the co-pilot's seat.
Only time we didn't was when scrambling in NBC IPE - what fun that was...
Brief clip of the station shows how much smarter things were back then - I can't believe how dreadfully shabby RAF stations look these days....
