(a) The control system must be investigated as follows for control surface loads due to ground gusts and taxiing downwind:
(1) If an investigation of the control system for ground gust loads is not required by paragraph (a)(2) of this section, but the applicant elects to design a part of the control system of these loads, these loads need only be carried from control surface horns through the nearest stops or gust locks and their supporting structures.
(2) If pilot forces less than the minimums specified in Sec. 23.397(b) are used for design, the effects of surface loads due to ground gusts and taxiing downwind must be investigated for the entire control system according to the formula: H=K c S q where-- H=limit hinge moment (ft.-lbs.);c=mean chord of the control surface aft of the hinge line (ft.);S=area of control surface aft of the hinge line (sq. ft.);q=dynamic pressure (p.s.f.) based on a design speed not less than 14.6
[radic](W/S) + 14.6 (f.p.s.) where W/S=wing loading at design
maximum weight, except that the design speed need not exceed
88 (f.p.s.);K=limit hinge moment factor for ground gusts derived in paragraph (b) of
this section. (For ailerons and elevators, a positive value of
K indicates a moment tending to depress the surface and a
negative value of K indicates a moment tending to raise the
surface).
(b) The limit hinge moment factor K for ground gusts must be derived as follows: ------------------------------------------------------------------------
(a) Aileron.................... 0.75 Control column locked lashed
in mid-position.(b) Aileron.................... Sec. 23.421 Balancing loads.
(a) A horizontal surface balancing load is a load necessary to maintain equilibrium in any specified flight condition with no pitching acceleration.
(b) Horizontal balancing surfaces must be designed for the balancing loads occurring at any point on the limit maneuvering envelope and in the flap conditions specified in Sec. 23.345. [Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23-7, 34 FR 13089, Aug. 13, 1969; Amdt. 23-42, 56 FR 352, Jan. 3, 1991]