Turbulence Speed on B757
Was on the North Atlantic Track the other day and we experienced some moderate turbulence. Since we are required to maintain Mach .80, no one ever slows down regardless of the turbulence encountered due to traffic encroachment in a non-radar environment. Yet, over land in a radar environment, nearly everyone I fly with slows to turbulence penetration speed of Mach .78.
I was told by the Captain that slowing to Mach .78 only helps reduce the buffer for Critical Mach and thus Mach buffeting.
Is this true? Isn't there any structural risks when not slowing? I would appreciate any technical insight.