Code of Federal Regulations

Title 14 - Aeronautics and Space
Volume: 1Date: 2023-01-01Original Date: 2023-01-01Title: Section 25.145 - Longitudinal control.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. - Controllability and Maneuverability.
§ 25.145 Longitudinal control. (a) It must be possible, at any point between the trim speed prescribed in § 25.103(b)(6) and stall identification (as defined in § 25.201(d)), to pitch the nose downward so that the acceleration to this selected trim speed is prompt with (1) The airplane trimmed at the trim speed prescribed in § 25.103(b)(6); (2) The landing gear extended; (3) The wing flaps (i) retracted and (ii) extended; and (4) Power (i) off and (ii) at maximum continuous power on the engines. (b) With the landing gear extended, no change in trim control, or exertion of more than 50 pounds control force (representative of the maximum short term force that can be applied readily by one hand) may be required for the following maneuvers: (1) With power off, flaps retracted, and the airplane trimmed at 1.3 V SR1 , extend the flaps as rapidly as possible while maintaining the airspeed at approximately 30 percent above the reference stall speed existing at each instant throughout the maneuver. (2) Repeat paragraph (b)(1) except initially extend the flaps and then retract them as rapidly as possible. (3) Repeat paragraph (b)(2), except at the go-around power or thrust setting. (4) With power off, flaps retracted, and the airplane trimmed at 1.3 V SR1 , rapidly set go-around power or thrust while maintaining the same airspeed. (5) Repeat paragraph (b)(4) except with flaps extended. (6) With power off, flaps extended, and the airplane trimmed at 1.3 V SR1 , obtain and maintain airspeeds between V SW and either 1.6 V SR1 or V FE , whichever is lower. (c) It must be possible, without exceptional piloting skill, to prevent loss of altitude when complete retraction of the high lift devices from any position is begun during steady, straight, level flight at 1.08 V SR1 for propeller powered airplanes, or 1.13 V SR1 for turbojet powered airplanes, with— (1) Simultaneous movement of the power or thrust controls to the go-around power or thrust setting; (2) The landing gear extended; and (3) The critical combinations of landing weights and altitudes. (d) If gated high-lift device control positions are provided, paragraph (c) of this section applies to retractions of the high-lift devices from any position from the maximum landing position to the first gated position, between gated positions, and from the last gated position to the fully retracted position. The requirements of paragraph (c) of this section also apply to retractions from each approved landing position to the control position(s) associated with the high-lift device configuration(s) used to establish the go-around procedure(s) from that landing position. In addition, the first gated control position from the maximum landing position must correspond with a configuration of the high-lift devices used to establish a go-around procedure from a landing configuration. Each gated control position must require a separate and distinct motion of the control to pass through the gated position and must have features to prevent inadvertent movement of the control through the gated position. It must only be possible to make this separate and distinct motion once the control has reached the gated position.
Code of Federal Regulations / Title 14 - Aeronautics and Space / Vol. 1 / 2023-01-01221
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25–23, 35 FR 5671, Apr. 8, 1970; Amdt. 25–72, 55 FR 29774, July 20, 1990; Amdt. 25–84, 60 FR 30749, June 9, 1995; Amdt. 25–98, 64 FR 6164, Feb. 8, 1999; 64 FR 10740, Mar. 5, 1999; Amdt. 25–108, 67 FR 70827, Nov. 26, 2002]