DERG
I don't see the logic in the above answers. In fact they are based on false premises.
How come you people think you can make up the rules of physics as you go along? Everytime I visit this type of thread I am always surprised at what you believe or have been taught.
If Boeing says the 'plane can do XYZ it will do XYZ : thats why they are late. Better late than have events like the A388 has suffered.
As far as the worry about buffeting goes maybe Boeing uses better math than Airbus does....
I am not saying that Boeing and Airbus know EVERYTHING about the products the make something like the 0,85 value does tell us about the airframe.
Every week there are quite serious events with people being thrown around in turbulence. Do you ever think about the stress on the airframe when these events happen?
Sorry DERG, but it your premises that are completely and utterly false.
As for the principles of physics, I don't make them up but at least I understand them so far as aircraft design is concerned, which is not always true in this thread! When I visit the thread I am in turn surprised as to how people with very little real knowledge can pontificate.
Buffeting has very little to do with mathematics, and if you had the remotest idea of aerodynamics you would know that the criterion on which a design should be judged is not Mach Number but the lift one can develop at a given Mach Number before the wing starts to buffet.
It is an anonymous forum which precludes biographical details, but in the light of your last remark I will just say that I was in overall charge of, inter alia, calculating the design loads for the A320, A330 and A340 aircraft, so yes, I have thought about the stress on the airframe when in turbulence - which incidentally does not result in serious events every week.
PS: Thank for your support PBL!