[Code of Federal Regulations]
[Title 14, Volume 1]
[Revised as of January 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 14CFR25.161]

[Page 355-356]
 
                     TITLE 14--AERONAUTICS AND SPACE
 
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
 
PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES--Table of Contents
 
                            Subpart B--Flight
 
Sec. 25.161  Trim.

    (a) General. Each airplane must meet the trim requirements of this 
section after being trimmed, and without further pressure upon, or 
movement of, either the primary controls or their corresponding trim 
controls by the pilot or the automatic pilot.
    (b) Lateral and directional trim. The airplane must maintain lateral 
and directional trim with the most adverse lateral displacement of the 
center of

[[Page 356]]

gravity within the relevant operating limitations, during normally 
expected conditions of operation (including operation at any speed from 
1.3 VSR1 to VMO/MMO).
    (c) Longitudinal trim. The airplane must maintain longitudinal trim 
during--
    (1) A climb with maximum continuous power at a speed not more than 
1.3 VSR1, with the landing gear retracted, and the 
flaps (i) retracted and (ii) in the takeoff position;
    (2) A glide with power off at a speed not more than 1.3 
VSR1, with the landing gear extended, the wing 
flaps (i) retracted and (ii) extended, the most unfavorable center of 
gravity position approved for landing with the maximum landing weight, 
and with the most unfavorable center of gravity position approved for 
landing regardless of weight; and
    (3) Level flight at any speed from 1.3 VSR1, 
to VMO/MMO, with the landing gear and flaps 
retracted, and from 1.3 VSR1 to VLE 
with the landing gear extended.
    (d) Longitudinal, directional, and lateral trim. The airplane must 
maintain longitudinal, directional, and lateral trim (and for the 
lateral trim, the angle of bank may not exceed five degrees) at 1.3 
VSR1 during climbing flight with--
    (1) The critical engine inoperative;
    (2) The remaining engines at maximum continuous power; and
    (3) The landing gear and flaps retracted.
    (e) Airplanes with four or more engines. Each airplane with four or 
more engines must maintain trim in rectilinear flight--
    (1) At the climb speed, configuration, and power required by 
Sec. 25.123(a) for the purpose of establishing the rate of climb;
    (2) With the most unfavorable center of gravity position; and
    (3) At the weight at which the two-engine-inoperative climb is equal 
to at least 0.013 VSR02 at an altitude of 5,000 
feet.

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-23, 
35 FR 5671, Apr. 8, 1970; Amdt. 25-38, 41 FR 55466, Dec. 20, 1976; Amdt. 
25-108, 67 FR 70827, Nov. 26, 2002]

                                Stability