Perhaps drifting away from the OPs intent, if it related solely to Military aircraft. I had some 500 hours solo experience of flying gliders over my time in the RAF. By basic trade I'm an Airframe tradesman, and was somewhat surprised when our CFI told me that modern gliders, spar wise, are stressed to take more than 20G loading, on account of spending most of our time in rough air and turbulence. His assertions were put to the test not long after when a fellow club member managed to fly into the blackest cu nim she could find that day. Her exit from the bottom of the cloud, minus wings, cost her her life. It appears she had found a way of exceeding whatever the true limits were on that aircraft, assisted by the nature of a violent piece of weather. As a C130 Ground Eng I never doubted the integrity of the airframe, yet could never forget seeing the wings fold on the firefighting Herk lost a few years after I left the service. i suspect though, that as is mentioned with the A10, designers "build in" strength based on the intended use of the aircraft. Who knows what happens when that aircraft is taken out of its designed environment. As a starter, the"Australia" patch on the underwing of the Vulcan, a direct result of its new low level role. I'm sure many others can offer input on the subject, it's certainly a "meaty" subject.
Smudge
