[Code of Federal Regulations]
[Title 14, Volume 1]
[Revised as of January 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 14CFR25.107]
[Page 350-351]
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
(3) A speed that provides the maneuvering capability specified in
Sec. 25.143(g).
[[Page 351]]
(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]