[Code of Federal Regulations]

[Title 14, Volume 1]

[Revised as of January 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 14CFR27.427]



[Page 580]

 

                     TITLE 14--AERONAUTICS AND SPACE

 

CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION

 

PART 27_AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT--Table 

of Contents

 

                     Subpart C_Strength Requirements

 

Sec. 27.427  Unsymmetrical loads.



    (a) Horizontal tail surfaces and their supporting structure must be 

designed for unsymmetrical loads arising from yawing and rotor wake 

effects in combination with the prescribed flight conditions.

    (b) To meet the design criteria of paragraph (a) of this section, in 

the absence of more rational data, both of the following must be met:

    (1) One hundred percent of the maximum loading from the symmetrical 

flight conditions acts on the surface on one side of the plane of 

symmetry, and no loading acts on the other side.

    (2) Fifty percent of the maximum loading from the symmetrical flight 

conditions acts on the surface on each side of the plane of symmetry but 

in opposite directions.

    (c) For empennage arrangements where the horizontal tail surfaces 

are supported by the vertical tail surfaces, the vertical tail surfaces 

and supporting structure must be designed for the combined vertical and 

horizontal surface loads resulting from each prescribed flight 

condition, considered separately. The flight conditions must be selected 

so the maximum design loads are obtained on each surface. In the absence 

of more rational data, the unsymmetrical horizontal tail surface loading 

distributions described in this section must be assumed.



[Admt. 27-26, 55 FR 7999, Mar. 6, 1990, as amended by Amdt. 27-27, 55 FR 

38966, Sept. 21, 1990]



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