CS 22.625 Fitting factors

CAA ORS9 Decision No. 1

For each fitting (a part or terminal used to join one structural member to another), the following apply: 

(a) For each fitting whose strength is not proven by limit and ultimate load tests in which actual stress conditions are simulated in the fitting and surrounding structures, a fitting factor of at least 1.15 must be applied to each part of – 

(1) the fitting; 

(2) the means of attachment; and 

(3) the bearing on the joined members. 

(b) No fitting factor need be used for joint designs based on comprehensive test data (such as continuous joints in metal plating, welded joints, and scarf joints in wood). 

(c) For each integral fitting, the part must be treated as a fitting up to the point at which the section properties become typical of the member. 

(d) For each seat, safety belt, and harness, its attachment to the structure must be shown, by analysis, tests, or both, to be able to withstand the inertia forces prescribed in CS 22.561 multiplied by a fitting factor of 1.33. 

(e) When using only two hinges at each control surface, or wing-flap, the safety factor for these hinges and the attached parts of the primary structure must be multiplied by a factor of 1.5.