High speed buffet at high altitude level flight lead to a stall?
An AVFACTS article date 2000 Lesson 5, Buffet Boundaries, VMO/MMO Limits, states:
Quote: "High speed jet aircraft may suffer both high and low speed stall buffet. The high speed buffet is caused by flow
separation from the wings as occurs behind a shockwave at high altitudes and/or Mach numbers. The low speed
buffet is caused by the same airflow separation as the aircraft approaches the stall angle of attack."
I am at loss to understand the quoted term "high speed stall buffet .
I always thought the high speed buffet such as that which occurs close to Vmo at high altitude was caused by shock wave action. I had no idea this buffet preceded a stall in level flight. . Obviously operation at the barber pole at high altitude will be characterised by increasing buffet but certainly the aircraft is not going to stall? Is it?
"Coffin Corner" I think means the joining of low speed buffet and high speed buffet either possibly causing grief through a low IAS stall at high altitude and on the other hand a potentially serious handling problem beyond Vne - but not a high angle of attack stall.
Having never heard the term used of high speed stall buffet (as against a G force stall buffet in a steep turn whether at low or high altitude), then maybe some could explain to me the meaning of the term as displayed in the opening line from the AVFAST article