Originally Posted by mike-wsm
The airplane was flying in 'coffin corner'. This is a strange part of the flight envelope where stall speed and the maximum mach number converge. (...)
At the flight level they were flying, I think it was fl370 or 37,000ft, the margin between airplane stall speed and structure maximum mach number was only 25 knots.
Actually, the airplane was flying at FL350, its 'coffin corner' was at FL460, and the margin between max. speed (Mmo=0.86; 295 kCAS) and low speed buffet (M=0.58; 192 kCAS) was 162 kTAS.
regards,
HN39