On an early B-707 transatlantic flight (with a load of passengers) there was some kind of autopilot malfunction, combined with the captain being back in the cabin passing out goodwill to the passengers; the ship got into a dive and they came close to losing it before it was back under control. A precautionary landing was made at Goose Bay or Gander. The wings were actually bent considerably. However, a thorough examination was made by a team of FAA and stress engineers and it was decided that the ship was safe to put back in service.
In engineering terms, this meant that "yield stress" was exceeded, but not "ultimate stress" which is typically about 1.5 times yield.
"The wings were actually bent considerably."
Geez, if the wings got bent in the recovery (pulling out of the dive) those poor people must have been subjected to some SERIOUS G's.
I wonder what the difference in wing shape would have done to the craft's flight/stall characteristics?
It often seems they were wonderfully unconcerned with minor details back in the day.