It is well written out in the 727 FCTM. I can't copy and paste it but it says that high mach affects stalls favourably. Separation starts at a more inboard location and at lower AOA leading to earlier warning and more pronounced pitchdown. It then mentions about the buffet occurring before artificial stall warning and says "Thus, the improved buffet warning and increased stall margins due to mach number effects give greater stall protection during high altitude flight"
So there you go. At least on this type, you have a greater stall margin. Then again, perhaps a lower margin for having to explain to somebody why you got buffeting in the first place.
One question. Once while cruising in a 737-200 we got above out target mach to maybe .76 but for sure it was below the barber pole. But all of a sudden we started getting some airframe vibration until the speed was reduced. Is this normal for this to happen when clearly below the barber pole?
Last edited by JammedStab; 5th Mar 2014 at 02:53.