Code of Federal Regulations - Title 14

375

Federal Aviation Administration, DOT

§ 25.107

= Load factor normal to the flight path

at V

MAX

W = Airplane gross weight;
S = Aerodynamic reference wing area; and
q = Dynamic pressure.

(b) V

CLMAX

is determined with:

(1) Engines idling, or, if that result-

ant thrust causes an appreciable de-
crease in stall speed, not more than
zero thrust at the stall speed;

(2) Propeller pitch controls (if appli-

cable) in the takeoff position;

(3) The airplane in other respects

(such as flaps, landing gear, and ice ac-
cretions) in the condition existing in
the test or performance standard in
which V

is being used;

(4) The weight used when V

is being

used as a factor to determine compli-
ance with a required performance
standard;

(5) The center of gravity position

that results in the highest value of ref-
erence stall speed; and

(6) The airplane trimmed for straight

flight at a speed selected by the appli-
cant, but not less than 1.13V

and not

greater than 1.3V

SR.

condition, apply the longitudinal con-
trol to decelerate the airplane so that
the speed reduction does not exceed
one knot per second.

(d) In addition to the requirements of

paragraph (a) of this section, when a
device that abruptly pushes the nose
down at a selected angle of attack (e.g.,
a stick pusher) is installed, the ref-
erence stall speed, V

, may not be less

than 2 knots or 2 percent, whichever is
greater, above the speed at which the
device operates.

[Doc. No. 28404, 67 FR 70825, Nov. 26, 2002, as
amended by Amdt. 25–121, 72 FR 44665, Aug. 8,
2007]

§ 25.105

Takeoff.

(a) The takeoff speeds prescribed by

§ 25.107, the accelerate-stop distance
prescribed by § 25.109, the takeoff path
prescribed by § 25.111, the takeoff dis-
tance and takeoff run prescribed by
§ 25.113, and the net takeoff flight path
prescribed by § 25.115, must be deter-
mined in the selected configuration for
takeoff at each weight, altitude, and
ambient temperature within the oper-
ational limits selected by the appli-
cant—

(1) In non-icing conditions; and
(2) In icing conditions, if in the con-

figuration of § 25.121(b) with the takeoff
ice accretion defined in appendix C:

(i) The stall speed at maximum take-

off weight exceeds that in non-icing
conditions by more than the greater of
3 knots CAS or 3 percent of V

; 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 re-
quire exceptional piloting skill or
alertness.

on—

(1) In the case of land planes and am-

phibians:

(i) Smooth, dry and wet, hard-sur-

faced 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 sea-

planes and amphibians; and

(3) Smooth, dry snow, in the case of

skiplanes.

(d) The takeoff data must include,

within the established operational lim-
its of the airplane, the following oper-
ational correction factors:

(1) Not more than 50 percent of nomi-

nal wind components along the takeoff
path opposite to the direction of take-
off, 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]

§ 25.107

Takeoff speeds.

(a) V

must be established in relation

to V

as follows:

(1) V

is the calibrated airspeed at

which the critical engine is assumed to
fail. V

must be selected by the appli-

cant, but may not be less than V

MCG

de-

termined under § 25.149(e).

(2) V

, in terms of calibrated air-

speed, is selected by the applicant;
however, V

may not be less than V

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