Text in force at CS25-28: from CS25-16, effective 13 Mar 2015.
(a) The take-off speeds prescribed by CS 25.107, the accelerate-stop distance prescribed by CS 25.109, the take-off path prescribed by CS 25.111, the take-off distance and take-off run prescribed by CS 25.113, and the net take-off flight path prescribed by CS 25.115, must be determined in the selected configuration for take-off at each weight, altitude, and ambient temperature within the operational limits selected by the applicant –
(1) In non-icing conditions; and
(2) In icing conditions, if in the configuration used to show compliance with CS 25.121(b), and 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):
(i) The stall speed at maximum take-off weight exceeds that in non-icing conditions by more than the greater of 5.6 km/h (3 knots) CAS or 3 % of VSR; or
(ii) The degradation of the gradient of climb determined in accordance with CS 25.121(b) is greater than one-half of the applicable actual-to-net take-off flight path gradient reduction defined in CS 25.115(b).
(b) No take-off made to determine the data required by this paragraph may require exceptional piloting skill or alertness.
(c) The take-off data must be based on:
(1) Smooth, dry and wet, hard-surfaced runways; and
(2) At the option of the applicant, grooved or porous friction course wet, hard-surfaced runways.
(d) The take-off data must include, within the established operational limits of the aeroplane, the following operational correction factors:
(1) Not more than 50 % of nominal wind components along the take-off path opposite to the direction of take-off, and not less than 150 % of nominal wind components along the take-off path in the direction of take-off.
(2) Effective runway gradients.
ED Decision 2015/008/R · Source