Thanks Brian, Well put . That looks like a great link. I will have a read when time permits.
Va (maneuvering speed) is the maximum speed at which a full, abrupt elevator movement, a gust, or a combination of the two will cause the wing to stall rather than bend. (The concept of maneuvering speed properly refers to symmetrical flight conditions, meaning no aileron or rudder involved. Somehow, the definition incorrectly got extended to include those surfaces.)
Good way to define it
and as you said here
Maneuvering speed is usually defined—without regard to asymmetrical loads—as the maximum speed at which full or abrupt combined control movements can be made without damaging the aircraft. The FAA’s AC 61-23C, “Pilot’s Handbook of Aeronautical Knowledge,” says that “any combination of flight control usage, including full deflection of the controls, or gust loads created by turbulence should not create an excessive air load if the airplane is operated below maneuvering speed.” According to the US Navy, “Any combination of maneuver and gust cannot create damage due to excess airload when the airplane is below the maneuver speed.”
The NTSB has pointed out that this broader definition, although widespread among pilots, is incorrect. Engineers consider each axis separately in designing for the air loads accompanying an abrupt, full control input at maneuvering speed. “Full inputs in more than one axis at the same time and multiple inputs in one axis are not considered in designing for these [VA] flight conditions.”
The particular “multiple inputs” that prompted NTSB comment were the rudder reversals leading to a yaw over swing followed by a final reversal that destroyed the vertical tail of American Airlines Flight 587 on November 12, 2001.
The old definition we were probably all taught at some point is just plain wrong.
