[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: 14CFR23.161]
[Page 196-197]
TITLE 14--AERONAUTICS AND SPACE
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
PART 23_AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND
COMMUTER CATEGORY AIRPLANES--Table of Contents
Subpart B_Flight
Sec. 23.161 Trim.
(a) General. Each airplane must meet the trim requirements of this
section after being trimmed and without further pressure upon, or
movement of, the primary controls or their corresponding trim controls
by the pilot or the automatic pilot. In addition, it must be possible,
in other conditions of loading, configuration, speed and power to ensure
that the pilot will not be unduly fatigued or distracted by the need to
apply residual control forces exceeding those for prolonged application
of Sec. 23.143(c). This applies in normal operation of the airplane
and, if applicable, to those conditions associated with the failure of
one engine for which performance characteristics are established.
(b) Lateral and directional trim. The airplane must maintain lateral
and directional trim in level flight with the landing gear and wing
flaps retracted as follows:
(1) For normal, utility, and acrobatic category airplanes, at a
speed of 0.9 VH, VC, or VMO/
MO, whichever is lowest; and
(2) For commuter category airplanes, at all speeds from 1.4
VS1 to the lesser of VH or VMO/
MMO.
(c) Longitudinal trim. The airplane must maintain longitudinal trim
under each of the following conditions:
(1) A climb with--
(i) Takeoff power, landing gear retracted, wing flaps in the takeoff
position(s), at the speeds used in determining the climb performance
required by Sec. 23.65; and
(ii) Maximum continuous power at the speeds and in the configuration
used in determining the climb performance required by Sec. 23.69(a).
(2) Level flight at all speeds from the lesser of VH and
either VNO or VMO/MMO (as appropriate),
to 1.4 VS1, with the landing gear and flaps retracted.
(3) A descent at VNO or VMO/MMO,
whichever is applicable, with power off and with the landing gear and
flaps retracted.
(4) Approach with landing gear extended and with--
(i) A 3 degree angle of descent, with flaps retracted and at a speed
of 1.4 VS1;
(ii) A 3 degree angle of descent, flaps in the landing position(s)
at VREF; and
(iii) An approach gradient equal to the steepest used in the landing
distance demonstrations of Sec. 23.75, flaps in the landing position(s)
at VREF.
(d) In addition, each multiple airplane must maintain longitudinal
and directional trim, and the lateral control force must not exceed 5
pounds at the speed used in complying with Sec. 23.67(a), (b)(2), or
(c)(3), as appropriate, with--
(1) The critical engine inoperative, and if applicable, its
propeller in the minimum drag position;
(2) The remaining engines at maximum continuous power;
(3) The landing gear retracted;
(4) Wing flaps retracted; and
(5) An angle of bank of not more than five degrees.
(e) In addition, each commuter category airplane for which, in the
determination of the takeoff path in accordance with Sec. 23.57, the
climb in the takeoff configuration at V2 extends beyond 400
feet above the takeoff surface, it must be possible to reduce the
longitudinal and lateral control forces to 10 pounds and 5 pounds,
respectively, and the directional control force must not exceed 50
pounds at V2 with--
(1) The critical engine inoperative and its propeller in the minimum
drag position;
(2) The remaining engine(s) at takeoff power;
(3) Landing gear retracted;
(4) Wing flaps in the takeoff position(s); and
[[Page 197]]
(5) An angle of bank not exceeding 5 degrees.
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23-21,
43 FR 2318, Jan. 16, 1978; Amdt. 23-34, 52 FR 1828, Jan. 15, 1987; Amdt.
23-42, 56 FR 351, Jan. 3, 1991; 56 FR 5455, Feb. 11, 1991; Amdt. 23-50,
61 FR 5189, Feb. 9, 1996]
Stability