I meant to post here earlier..
This is a quote from Fighter Combat by Robert Shaw. In turn, it looks like he got it from The Look of Eagles by John Godfrey, a USAAF ace flying on the Western Front during WW2.
"We were both flying in a tight circle. Just a little more and I'll have him[\i]. Pressing the tit, I waited expectantly for the 109 to explode. I've hit his wing. A section two feet long broke loose from the right wing as the machine gun bullets cut like a machete through it. Too low, a little more rudder and the bullets will find his cockpit. I could see occasional strikes farther up the wing, but it was to late. The 109, sensing that I was inside him on the turn, slunk into a nearby cloud."
Whats that sound like to you? To me, it sounds rather like structural damage.