Capt Claret: in 1979, following failure of an American Airlines DC-10 engine pylon, with separation of the engine and damage to the leading edge, one slat retracted.
But the crew had no indication of the change. They only thought that the engine had flamed-out, until the plane rolled out of control.
Maintenance technicians at the Tulsa facility used a very wrong procedure to change the engine under the wing.