[Code of Federal Regulations]
[Title 14, Volume 1]
[Revised as of January 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 14CFR25.107]
[Page 344-345]
TITLE 14--AERONAUTICS AND SPACE
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES--Table of Contents
Subpart B--Flight
Sec. 25.107 Takeoff speeds.
(a) V1 must be established in relation to VEF
as follows:
(1) VEF is the calibrated airspeed at which the critical
engine is assumed to fail. VEF must be selected by the
applicant, but may not be less than VMCG determined under
Sec. 25.149(e).
(2) V1, in terms of calibrated airspeed, is selected by
the applicant; however, V1 may not be less than
VEF plus the speed gained with critical engine inoperative
during the time interval between the instant at which the critical
engine is failed, and the instant at which the pilot recognizes and
reacts to the engine failure, as indicated by the pilot's initiation of
the first action (e.g., applying brakes, reducing thrust, deploying
speed brakes) to stop the airplane during accelerate-stop tests.
(b) V2MIN, in terms of calibrated airspeed, may not be
less than--
(1) 1.13 VSR for--
(i) Two-engine and three-engine turbopropeller and reciprocating
engine powered airplanes; and
(ii) Turbojet powered airplanes without provisions for obtaining a
significant reduction in the one-engine-inoperative power-on stall
speed;
(2) 1.08 VSR for--
(i) Turbopropeller and reciprocating engine powered airplanes with
more than three engines; and
(ii) Turbojet powered airplanes with provisions for obtaining a
significant reduction in the one-engine-inoperative power-on stall
speed; and
(3) 1.10 times VMC established under Sec. 25.149.
(c) V2, in terms of calibrated airspeed, must be selected
by the applicant to provide at least the gradient of climb required by
Sec. 25.121(b) but may not be less than--
(1) V2MIN;
(2) VR plus the speed increment attained (in accordance
with Sec. 25.111(c)(2)) before reaching a height of 35 feet above the
takeoff surface; and
[[Page 345]]
(3) A speed that provides the maneuvering capability specified in
Sec. 25.143(g).
(d) VMU is the calibrated airspeed at and above which the
airplane can safely lift off the ground, and con- tinue the takeoff.
VMU speeds must be selected by the applicant throughout the
range of thrust-to-weight ratios to be certificated. These speeds may be
established from free air data if these data are verified by ground
takeoff tests.
(e) VR, in terms of calibrated airspeed, must be selected
in accordance with the conditions of paragraphs (e)(1) through (4) of
this section:
(1) VR may not be less than--
(i) V1;
(ii) 105 percent of VMC;
(iii) The speed (determined in accordance with Sec. 25.111(c)(2))
that allows reaching V2 before reaching a height of 35 feet
above the takeoff surface; or
(iv) A speed that, if the airplane is rotated at its maximum
practicable rate, will result in a VLOF of not less than 110
percent of VMU in the all-engines-operating condition and not
less than 105 percent of VMU determined at the thrust-to-
weight ratio corresponding to the one-engine-inoperative condition.
(2) For any given set of conditions (such as weight, configuration,
and temperature), a single value of VR, obtained in
accordance with this paragraph, must be used to show compliance with
both the one-engine-inoperative and the all-engines-operating takeoff
provisions.
(3) It must be shown that the one-engine-inoperative takeoff
distance, using a rotation speed of 5 knots less than VR
established in accordance with paragraphs (e)(1) and (2) of this
section, does not exceed the corresponding one-engine-inoperative
takeoff distance using the established VR. The takeoff
distances must be determined in accordance with Sec. 25.113(a)(1).
(4) Reasonably expected variations in service from the established
takeoff procedures for the operation of the airplane (such as over-
rotation of the airplane and out-of-trim conditions) may not result in
unsafe flight characteristics or in marked increases in the scheduled
takeoff distances established in accordance with Sec. 25.113(a).
(f) VLOF is the calibrated airspeed at which the airplane
first becomes airborne.
(g) VFTO, in terms of calibrated airspeed, must be
selected by the applicant to provide at least the gradient of climb
required by Sec. 25.121(c), but may not be less than--
(1) 1.18 VSR; and
(2) A speed that provides the maneuvering capability specified in
Sec. 25.143(g).
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-38,
41 FR 55466, Dec. 20, 1976; Amdt. 25-42, 43 FR 2320, Jan. 16, 1978;
Amdt. 25-92, 63 FR 8318, Feb. 18, 1998; Amdt. 25-94, 63 FR 8848, Feb.
23, 1998; Amdt. 25-108, 67 FR 70826, Nov. 26, 2002]