Facts
At the time of the accident, AF447's "coffin corner" was at FL460. Shortly before that, the airplane was in cruise at FL350, M.82 (280 kCAS). The available range of safe speeds at that altitude was from M.58 (192 kCAS) to M.86 (295 kCAS). It would take 2.5 minutes to decelerate from M.82 to M.58, the low-speed boundary for the onset of perceptible buffet, in level flight at zero thrust, and somewhat longer at idle.
Regards,
HN39
Last edited by HazelNuts39; 26th March 2011 at 21:14.