I heard 300 to 400 mph when the plane started raining parts. I am Nanc but not John Nance.
I've heard reports like that too, but from newsreaders, not knowledgable sources. Another poster earlier mentioned that over 250 knots was illegal under 10,000 feet.
That being said, it's possible the plane was going faster if the speculation is true that the pilots were attempting an energency acceleration to stabilize the plane.
I'm just waiting for the facts.