When I was in the RAF we used to have engineering sections that serviced, stripped and repaired aircraft engines, do they not do this any longer? It wouldn't surprise me as my own trade was dumbed down from investigating and fixing faults to component changers in the thirteen years I was a mechanical engineer (trade group 5).
My brother in law used to work for Rolls Royce and part of his job was doing ultra-sound, etc. testing on parts after someone else stripped them down - there was a whole massive process with in-depth fatigue testing, etc. before anything would get remotely close to being reused. I don't know the ins and outs of it but I believe they handle a lot of that stuff for the military now rather than the military having the same scale of engineering sections - though obviously they maintain some of that ability.