I don't have many details, but my Uncle George Carpenter was an aircraft repairman with the Eighth in England. He told me that the ground repair crew were required to fly on the occasional mission as a gunner as part of the "Quality Control" program. The closest he came to being killed was when a P-51 had an accidental discharge on the airfield and sent a stream of 50 cal into the roof of his barracks and blowing away the second floor.
His claim to fame was that he invented a field expedient pneumatic bucking bar to do riveted repairs to interior spars. Boeing heard about it and came to see how it worked. As he tells it, they went back to the US and put it into the production lines to speed up construction. It's indirect evidence, but there seems to be some amount of riveted aluminum repair going on in the field.
When he got back from the war he went to work for Pratt and Whitney in East Hartford as a machinist, and eventually became the Foreman of the Prototype / Model Shop, working on their interesting transition from radial engines to jets.
