I was never a Victor driver ..... so ..... Cunnane was flying a B1A/K2P at 41,000 ft. The B1A was capable of 645 mph at 35,000 and had a ceiling of 55,000 ft. What the B1A was capable of at 41,000 I don't know (630?) but he had been cruising at 0.9 - 594 mph. Mach 1 at 41,000 is around 660 mph so maybe 30+ mph in a shallow dive over its presumed level max to get an indicated mach 1? Is that too big a leap?