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Old 12th Jun 2009, 14:56
  #1275 (permalink)  
elch
 
Join Date: Sep 2008
Location: Italy
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Rudder and vma

When the upset recovery training came up we heavily contested the military derived rudder recovery usage ( sky rudder they said ). Best way to loose an aircraft by control inputs beyond FAR certification:

Code of Federal Regulations


Sec. 25.351

Part 25 AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES
Subpart C--Structure
Flight Maneuver and Gust Conditions

Sec. 25.351

[Yaw maneuver] conditions.

[The airplane must be designed for loads resulting from yaw maneuver conditions specified in paragraphs (a) through (d) of this section at speeds from VMC to VD. Unbalanced aerodynamic moments about the center of gravity must be reacted in a rational or conservative manner considering the airplane inertia forces. In computing the tail loads the yawing velocity may be assumed to be zero.
(a) With the airplane in unaccelerated flight at zero yaw, it is assumed that the cockpit rudder control is suddenly displaced to achieve the resulting rudder deflection, as limited by:
(1) The control system on control surface stops; or
(2) A limit pilot force of 300 pounds from VMC to VA and 200 pounds from VC / MC to VD / MD, with a linear variation between VA and VC / MC.
(b) With the cockpit rudder control deflected so as always to maintain the maximum rudder deflection available within the limitations specified in paragraph (a) of this section, it is assumed that the airplane yaws to the overswing sideslip angle.
(c) With the airplane yawed to the static equilibrium sideslip angle, it is assumed that the cockpit rudder control is held so as to achieve the maximum rudder deflection available within the limitations specified in paragraph (a) of this section.
(d) With the airplane yawed to the static equilibrium sideslip angle of paragraph (c) of this section, it is assumed that the cockpit rudder control is suddenly returned to neutral.]

Amdt. 25-91, Eff. 7/29/97
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