As an aside -- most (all?) Boeing FCOMs have a note about flap extension not being permitted above 20,000ft. Some might (and do) argue the wording implies that the limitation is for the action of extension, not having flaps extended per se. What it most likely means is that during certification the highest the test pilots flew with flap extended was 20,000ft and therefore flight with flap extended above this altitude has not been tested -- it does not necessarily mean that the wings will fall off and the aircraft will instantly go out of control if you fly above 20,000ft with the flaps out, just that it has not been tested and therefore nobody really knows what will happen -- in effect, if you do so you are becoming a test pilot.
 

Thanks for the insight, skelsey!  That makes sense...

This is a famous accident...a book even pagliarised this accident.

 

https://aviation-safety.net/database/record.php?id=19930406-2