CS 25.111 Take-off path

ED Decision 2015/008/R

(See AMC 25.111)

(a)     The take-off path extends from a standing start to a point in the take-off at which the aeroplane is 457 m (1500 ft) above the take-off surface, or at which the transition from the take-off to the en-route configuration is completed and V_FTO is reached, whichever point is higher. In addition –

(1)     The take-off path must be based on the procedures prescribed in CS 25.101(f);

(2)     The aeroplane must be accelerated on the ground to V_EF, at which point the critical engine must be made inoperative and remain inoperative for the rest of the take-off; and

(3)     After reaching V_EF, the aeroplane must be accelerated to V₂.

(b)     During the acceleration to speed V₂, the nose gear may be raised off the ground at a speed not less than V_R. However, landing gear retraction may not be begun until the aeroplane is airborne. (See AMC 25.111(b).)

(c)      During the take-off path determination in accordance with sub-paragraphs (a) and (b) of this paragraph –

(1)     The slope of the airborne part of the take-off path must be positive at each point;

(2)     The aeroplane must reach V₂ before it is 11 m (35 ft) above the take-off surface and must continue at a speed as close as practical to, but not less than V₂ until it is 122 m (400 ft) above the take-off surface;

(3)     At each point along the take-off path, starting at the point at which the aeroplane reaches 122 m (400 ft) above the take-off surface, the available gradient of climb may not be less than –

(i)      1·2% for two-engined aeroplanes;

(ii)     1·5% for three-engined aeroplanes; and

(iii)     1·7% for four-engined aeroplanes,

(4)     The aeroplane configuration may not be changed, except for gear retraction and automatic propeller feathering, and no change in power or thrust that requires action by the pilot may be made, until the aeroplane is 122 m (400 ft) above the take-off surface, and

(5)     If CS 25.105(a)(2) requires the take-off path to be determined for flight in icing conditions, the airborne part of the take-off must be based on the aeroplane drag:

(i)      With the most critical of the “Take-off Ice” accretion(s) defined in Appendices C and O, as applicable, in accordance with CS 25.21(g), from a height of 11 m (35 ft) above the take-off surface up to the point where the aeroplane is 122 m (400 ft) above the take-off surface; and

(ii)     With the most critical of the “Final Take-off Ice” accretion(s) defined in Appendices C and O, as applicable, in accordance with CS 25.21(g), from the point where the aeroplane is 122 m (400 ft) above the take-off surface to the end of the take-off path.

 (d)    The take-off path must be determined by a continuous demonstrated take-off or by synthesis from segments. If the take-off path is determined by the segmental method –

(1)     The segments must be clearly defined and must relate to the distinct changes in the configuration, power or thrust, and speed;

(2)     The weight of the aeroplane, the configuration, and the power or thrust must be constant throughout each segment and must correspond to the most critical condition prevailing in the segment;

(3)     The flight path must be based on the aeroplane’s performance without ground effect; and

(4)     The take-off path data must be checked by continuous demonstrated take-offs up to the point at which the aeroplane is out of ground effect and its speed is stabilised, to ensure that the path is conservative to the continuous path.

The aeroplane is considered to be out of the ground effect when it reaches a height equal to its wing span.

(e)     Not required for CS-25.

[Amdt 25/3]

[Amdt 25/16]