(1) In non-icing conditions; and
(2) In icing conditions, if in the configuration of §25.121(b) with the takeoff ice accretion defined in appendix C:
(i) The stall speed at maximum takeoff weight exceeds that in non-icing conditions by more than the greater of 3 knots CAS or 3 percent of VSR; or
(ii) The degradation of the gradient of climb determined in accordance with §25.121(b) is greater than one-half of the applicable actual-to-net takeoff flight path gradient reduction defined in §25.115(b).
(b) No takeoff made to determine the data required by this section may require exceptional piloting skill or alertness.
(c) The takeoff data must be based on—
(1) In the case of land planes and amphibians:
(i) Smooth, dry and wet, hard-surfaced runways; and
(ii) At the option of the applicant, grooved or porous friction course wet, hard-surfaced runways.
(2) Smooth water, in the case of seaplanes and amphibians; and
(3) Smooth, dry snow, in the case of skiplanes.
(d) The takeoff data must include, within the established operational limits of the airplane, the following operational correction factors:
(1) Not more than 50 percent of nominal wind components along the takeoff path opposite to the direction of takeoff, and not less than 150 percent of nominal wind components along the takeoff path in the direction of takeoff.
(2) Effective runway gradients.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25–92, 63 FR 8318, Feb. 18, 1998; Amdt. 25–121, 72 FR 44665, Aug. 8, 2007]