Code of Federal Regulations (alpha)

CFR /  Title 14  /  Part 23  /  Sec. 23.397 Limit control forces and torques.

(a) In the control surface flight loading condition, the airloads on movable surfaces and the corresponding deflections need not exceed those that would result in flight from the application of any pilot force within the ranges specified in paragraph (b) of this section. In applying this criterion, the effects of control system boost and servo-mechanisms, and the effects of tabs must be considered. The automatic pilot effort must be used for design if it alone can produce higher control surface loads than the human pilot.

(b) The limit pilot forces and torques are as follows: ------------------------------------------------------------------------

Maximum forces or

torques for design

weight, weight Minimum forces or

Control equal to or less torques \2\

than 5,000 pounds

\1\------------------------------------------------------------------------Aileron:

Stick......................... 67 lbs............ 40 lbs.

Wheel \3\..................... 50 D in.-lbs \4\.. 40 D in.-lbs.\4\Elevator:

Stick......................... 167 lbs........... 100 lbs.

Wheel (symmetrical)........... 200 lbs........... 100 lbs.

Wheel (unsymmetrical) \5\..... .................. 100 lbs.Rudder.......................... 200 lbs........... 150 lbs.------------------------------------------------------------------------\1\ For design weight (W) more than 5,000 pounds, the specified maximum

values must be increased linearly with weight to 1.18 times the

specified values at a design weight of 12,500 pounds and for commuter

category airplanes, the specified values must be increased linearly

with weight to 1.35 times the specified values at a design weight of

19,000 pounds.

\2\ If the design of any individual set of control systems or surfaces

makes these specified minimum forces or torques inapplicable, values

corresponding to the present hinge moments obtained under Sec.

23.415, but not less than 0.6 of the specified minimum forces or

torques, may be used.\3\ The critical parts of the aileron control system must also be

designed for a single tangential force with a limit value of 1.25

times the couple force determined from the above criteria.\4\ D=wheel diameter (inches).\5\ The unsymmetrical force must be applied at one of the normal

handgrip points on the control wheel. [Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23-7, 34 FR 13089, Aug. 13, 1969; Amdt. 23-17, 41 FR 55464, Dec. 20, 1976; Amdt. 23-34, 52 FR 1829, Jan. 15, 1987; Amdt. 23-45, 58 FR 42160, Aug. 6, 1993]