Code of Federal Regulations

Title 14 - Aeronautics and Space
Volume: 1Date: 2023-01-01Original Date: 2023-01-01Title: Section 25.161 - Trim.Context: Title 14 - Aeronautics and Space. CHAPTER I - FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION. SUBCHAPTER C - AIRCRAFT. PART 25 - AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES. Subpart B - Flight. - Trim.
§ 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 gravity within the relevant operating limitations, during normally expected conditions of operation (including operation at any speed from 1.3 V SR 1 to V MO /M MO ). (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 V SR 1 , with the landing gear retracted, and the flaps (i) retracted and (ii) in the takeoff position; (2) Either a glide with power off at a speed not more than 1.3 V SR1 , or an approach within the normal range of approach speeds appropriate to the weight and configuration with power settings corresponding to a 3 degree glidepath, whichever is the most severe, with the landing gear extended, the wing flaps (i) retracted and (ii) extended, and with the most unfavorable combination of center of gravity position and weight approved for landing; and (3) Level flight at any speed from 1.3 V SR 1 , to V MO /M MO, with the landing gear and flaps retracted, and from 1.3 V SR 1 to V LE 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 V SR 1 during climbing flight with—
Code of Federal Regulations / Title 14 - Aeronautics and Space / Vol. 1 / 2023-01-01224
(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 also maintain trim in rectilinear flight with the most unfavorable center of gravity and at the climb speed, configuration, and power required by § 25.123(a) for the purpose of establishing the en route flight paths with two engines inoperative. [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; Amdt. 25–115, 69 FR 40527, July 2, 2004]