CS-VLA 415 Ground gust conditions
ED Decision 2003/18/RM
(a) The control system must be investigated as follows for control surface loads due to ground gusts and taxying downwind:
(1) If an investigation of the control system for ground gust loads is not required by sub-paragraph (a)(2) of this paragraph, but the applicant elects to design a part of the control system for 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 minimum forces specified in CS-VLA 397(b) are used for design, the effects of surface loads due to ground gusts and taxying downwind must be investigated for the entire control system according to the formula -
where -
H = limit hinge moment (Nm);
c = mean chord of the control surface aft of the hinge line (m);
S = area of the control surface aft of the hinge line (m2);
q = dynamic pressure (Pa) based on a design speed not less than 2.01 √ M/S + 4.45 (m/s), except that the design speed need not exceed 26.8 m/s; and
K = limit hinge moment factor for ground gusts derived in sub-paragraph (b). (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:
|
Surface |
K |
Position of control |
|
|
(a) |
Aileron |
0.75 |
Control column locked or lashed in mid-position |
|
(b) |
Aileron |
±0.50 |
Ailerons at full throw; +moment on one aileron -moment on the other |
|
(c) |
Elevator |
±0.75 |
(c) Elevator full up (-) |
|
(d) |
(d) Elevator full down (+) |
||
|
(e) |
Rudder |
±0.75 |
(e) Rudder in neutral |
|
(f) |
(f) Rudder at full throw |
||