747FOCAL, you stated
´I doubt there is any input a pilot could do that should make control surfaces or the tail or engines come off a plane if it satisfies all FAR requirements for structural integrity.´
Just look at FAR 25.361 and you shurely believe a pilot can overstress a plane´s tail :
14 CFR 25 Sec. 25.351 Yawing conditions.
The airplane must be designed for loads resulting from the conditions specified in paragraph (a) of this section. Unbalanced aerodynamic moments about the center of gravity must be reacted in a rational or conservative manner considering the principal masses furnishing the reacting inertia forces:
(a) Maneuvering. At speeds from VMC to VD, the following maneuvers must be considered. In computing the tail loads, the yawing velocity may be assumed to be zero:
(1) With the airplane in unaccelerated flight at zero yaw, it is assumed that the rudder control is suddenly displaced to the maximum deflection, as limited by the control surface stops, or by a 300-pound rudder pedal force, whichever is less.
(2) With the rudder deflected as specified in paragraph (a)(1) of this section, it is assumed that the airplane yaws to the resulting sideslip angle.
(3) With the airplane yawed to the static sideslip angle corresponding to the rudder deflection specified in paragraph (a)(1) of this section, it is assumed that the rudder is returned to neutral.
(b) [Reserved]
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-23, 35 FR 5672, Apr. 8, 1970; Amdt. 25-46, 43 FR 50595, Oct. 30, 1978; Amdt. 25-72, 55 FR 29775, July 20, 1990; 55 FR 37608, Sept. 12, 1990; 55 FR 41415, Oct. 11, 1990; Amdt. 25-86, 61 FR 5222, Feb. 9, 1996]
So just apply full rudder (FAR 25.361 (1)), wait for maximum sideslip angle (FAR 25.361 (2)), dont just return rudder to neutral as specified in (FAR 25.361 (3)) but apply full opposite rudder and you shurely overstess your airframe. And in this case the yawing speed is not even accounted for, for a plane wich such a long aft fuselage it produces another amount of effective tail fin angle of attack. Additionally the maximum dynamic sideslip angle is much larger than the static one, so it is easyly possible to produce about twice the angle of attack dynamically and apply rudder in the direction that increases aerodynamic forces. European JAR 25.361 is just the same as the FAR requirement.
As my structural design professor always said : It is impossible to design a plane that can not be destroyed by wrong pilot control inputs at the right speed and flight attitude. (might not be true for fighter airplane where the physical capabilities of the pilot are the limiting factor and the pilot rather kills himself before breaking the airframe)
There are some more paragraphs important for structural design of the fin like lateral gustloads and single engine failure loads, so it is not clear if the 25.351 yawing condition is the most critical for a specific airplane. But it is for shure possible to exceed the loads specified in this paragraph.