Lu, did you write the words "and CFR-14-27.351 requires full deflection of the tail rotor pedals (left and right) while airborne from 0 to 0.6 Vne to attain a 90-degree sideslip" ??
Did you? If you did, you were wrong. Period.
I guess you didn't mean "while airborne" to infer that this is flown, in the air, above the ground, while airborne. I guess you don't know what you mean.
Why do you keep on pretending you know what you are talking about when you don't even know what you said? Do you think we don't know what you said?