Sec. 25.445 - Auxiliary aerodynamic surfaces.
(a) When significant, the aerodynamic
influence between auxiliary aerodynamic surfaces, such as outboard fins
and winglets, and their supporting aerodynamic surfaces, must be taken
into account for all loading conditions including pitch, roll, and yaw
maneuvers, and gusts as specified in §25.341(a) acting at any orientation
at right angles to the flight path.
(b) To provide for unsymmetrical loading
when outboard fins extend above and below the horizontal surface, the
critical vertical surface loading (load per unit area) determined under
§25.391 must also be applied as follows:
(1) 100 percent to the area of the
vertical surfaces above (or below) the horizontal surface.
(2) 80 percent to the area below (or
above) the horizontal surface.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25-86, 61 FR 5222, Feb. 9, 1996]