[Code of Federal Regulations]
[Title 14, Volume 1]
[Revised as of January 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 14CFR25.121]

[Page 357-358]
 
                     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.  25.121  Climb: One-engine-inoperative.

    (a) Takeoff; landing gear extended. In the critical takeoff 
configuration existing along the flight path (between the points at 
which the airplane reaches VLOF and at which the landing gear is fully 
retracted) and in the configuration used in Sec.  25.111 but without 
ground effect, the steady gradient of climb must be positive for two-
engine airplanes, and not less than 0.3 percent for three-engine 
airplanes or 0.5 percent for four-engine airplanes, at VLOF and with--
    (1) The critical engine inoperative and the remaining engines at the 
power

[[Page 358]]

or thrust available when retraction of the landing gear is begun in 
accordance with Sec.  25.111 unless there is a more critical power 
operating condition existing later along the flight path but before the 
point at which the landing gear is fully retracted; and
    (2) The weight equal to the weight existing when retraction of the 
landing gear is begun, determined under Sec.  25.111.
    (b) Takeoff; landing gear retracted. In the takeoff configuration 
existing at the point of the flight path at which the landing gear is 
fully retracted, and in the configuration used in Sec.  25.111 but 
without ground effect, the steady gradient of climb may not be less than 
2.4 percent for two-engine airplanes, 2.7 percent for three-engine 
airplanes, and 3.0 percent for four-engine airplanes, at V2 
and with--
    (1) The critical engine inoperative, the remaining engines at the 
takeoff power or thrust available at the time the landing gear is fully 
retracted, determined under Sec.  25.111, unless there is a more 
critical power operating condition existing later along the flight path 
but before the point where the airplane reaches a height of 400 feet 
above the takeoff surface; and
    (2) The weight equal to the weight existing when the airplane's 
landing gear is fully retracted, determined under Sec.  25.111.
    (c) Final takeoff. In the en route configuration at the end of the 
takeoff path determined in accordance with Sec.  25.111, the steady 
gradient of climb may not be less than 1.2 percent for two-engine 
airplanes, 1.5 percent for three-engine airplanes and 1.7 percent for 
four-engine airplanes, at VFTO and with
    (1) The critical engine inoperative and the remaining engines at the 
available maximum continuous power or thrust; and
    (2) The weight equal to the weight existing at the end of the 
takeoff path, determined under Sec.  25.111.
    (d) Approach. In a configuration corresponding to the normal all-
engines-operating procedure in which VSR for this configuration does not 
exceed 110 percent of the VSR for the related all-engines-operating 
landing configuration, the steady gradient of climb may not be less than 
2.1 percent for two-engine airplanes, 2.4 percent for three-engine 
airplanes, and 2.7 percent for four engine airplanes, with
    (1) The critical engine inoperative, the remaining engines at the 
go-around power or thrust setting;
    (2) The maximum landing weight;
    (3) A climb speed established in connection with normal landing 
procedures, but not more than 1.4 VSR; and
    (4) Landing gear retracted.

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-84, 
60 FR 30749, June 9, 1995; Amdt. 25-108, 67 FR 70826, Nov. 26, 2002]