Boeing test pilot Tex Johnston barrel rolled the Dash 80, the prototype 707. This is well documented by witness and film and has been often discussed on SDMB. I am not aware of anyone who put the greasy side of a 747 on top.
True, but most radio altimeters “top out” at 2,500 feet AGL. Anything higher than that and the display is blanked.
They might have noticed it on the way down, but the airplane was unrecoverable by that point.
And on preview I’m beaten to the punch re: the barrel-rolling 707.