Sec. 23.701 - Flap interconnection.
(a) The main wing flaps and related
movable surfaces as a system must --
(1) Be synchronized by a mechanical
interconnection between the movable flap surfaces that is independent of
the flap drive system; or by an approved equivalent means; or
(2) Be designed so that the occurrence
of any failure of the flap system that would result in an unsafe flight
characteristic of the airplane is extremely improbable; or
(b) The airplane must be shown to have
safe flight characteristics with any combination of extreme positions of
individual movable surfaces (mechanically interconnected surfaces are to
be considered as a single surface).
(c) If an interconnection is used in
multiengine airplanes, it must be designed to account for the
unsummetrical loads resulting from flight with the engines on one side of
the plane of symmetry inoperative and the remaining engines at takeoff
power. For single-engine airplanes, and multiengine airplanes with no
slipstream effects on the flaps, it may be assumed that 100 percent of the
critical air load acts on one side and 70 percent on the other.
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as
amended by Amdt. 23-14, 38 FR 31821, Nov. 19, 1973; Amdt. 23-42, 56 FR
353, Jan. 3, 1991; 56 FR 5455, Feb. 11, 1991; Amdt. 23-49, 61 FR 5165,
Feb. 9, 1996]