CS 25.145 Longitudinal control

ED Decision 2018/005/R

(a)     (See AMC 25.145(a).) It must be possible at any point between the trim speed prescribed in CS 25.103(b)(6) and stall identification (as defined in CS 25.201(d)), to pitch the nose downward so that the acceleration to this selected trim speed is prompt with:

(1)     the aeroplane trimmed at the trim speed prescribed in CS 25.103(b)(6);

(2)     the most critical landing gear configuration;

(3)     the wing-flaps (i) retracted and (ii) extended; and

(4)     engine trust or power (i) off and (ii) at go-around setting.

(b)     With the landing gear extended, no change in trim control, or exertion of more than 222 N (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 manoeuvres:

(1)     With power off, wing-flaps retracted, and the aeroplane trimmed at 1·3 V_SR1, extend the wing-flaps as rapidly as possible while maintaining the airspeed at approximately 30% above the reference stall speed existing at each instant throughout the manoeuvre. (See AMC 25.145(b)(1), (b)(2) and (b)(3).)

(2)     Repeat sub-paragraph (b)(1) of this paragraph except initially extend the wing-flaps and then retract them as rapidly as possible. (See AMC 25.145(b)(2) and AMC 25.145(b)(1), (b)(2) and (b)(3).)

(3)     Repeat sub-paragraph (b)(2) of this paragraph except at the go-around power or thrust setting. (See AMC 25.145(b)(1), (b)(2) and (b)(3).)

(4)     With power off, wing-flaps retracted and the aeroplane trimmed at 1·3 V_SR1, rapidly set go-around power or thrust while maintaining the same airspeed.

(5)     Repeat sub-paragraph (b)(4) of this paragraph except with wing-flaps extended.

(6)     With power off, wing-flaps extended and the aeroplane trimmed at 1·3 V_SR1 obtain and maintain airspeeds between V_SW and either 1·6 V_SR1, or V_FE, whichever is the 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 aeroplanes or 1·13 V_SR1, for turbo-jet powered aeroplanes, 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)     Revoked

(e)     (See AMC 25.145(e).) If gated high-lift device control positions are provided, sub-paragraph (c) of this paragraph 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 sub-paragraph (c) of this paragraph 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.

(f)      It must be possible to maintain adequate longitudinal and speed control under the following conditions without exceptional piloting skill, alertness, or strength, without danger of exceeding the aeroplane limit-load factor and while maintaining an adequate stall margin throughout the manoeuvre:

(1)     Starting with the aeroplane in each approved approach and landing configuration, trimmed longitudinally and with the thrust or power setting per CS 25.161(c)(2), perform a go-around, transition to the next flight phase and level off at the desired altitude:

(i)      with all engines operating and the thrust or power controls moved to the go-around power or thrust setting;

(ii)      with the configuration changes, as per the approved operating procedures or conventional operating practices; and

(iii) with any practicable combination of Flight Guidance/Autothrust-throttle/Autopilot to be approved, including manual.

(2)      Reasonably expected variations in service from the established approach, landing and go-around procedures for the operation of the aeroplane must not result in unsafe flight characteristics during the go-around.

[Amdt 25/18]

[Amdt 25/21]