[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: 14CFR23.149]

[Page 188-189]
 
                     TITLE 14--AERONAUTICS AND SPACE
 
CHAPTER I--FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
 
PART 23--AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES--Table of Contents
 
                            Subpart B--Flight
 
Sec. 23.149  Minimum control speed.

    (a) VMC is the calibrated airspeed at which, when the 
critical engine is suddenly made inoperative, it is possible to maintain 
control of the airplane with that engine still inoperative, and 
thereafter maintain straight flight at the same speed with an angle of 
bank of not more than 5 degrees. The method used to simulate critical 
engine failure must represent the most critical mode of powerplant 
failure expected in service with respect to controllability.
    (b) VMC for takeoff must not exceed 1.2 VS1, 
where VS1 is determined at the maximum takeoff weight. 
VMC must be determined with the most unfavorable weight and 
center of gravity position and with the airplane airborne and the ground 
effect negligible, for the takeoff configuration(s) with--
    (1) Maximum available takeoff power initially on each engine;
    (2) The airplane trimmed for takeoff;
    (3) Flaps in the takeoff position(s);
    (4) Landing gear retracted; and
    (5) All propeller controls in the recommended takeoff position 
throughout.
    (c) For all airplanes except reciprocating engine-powered airplanes 
of 6,000 pounds or less maximum weight, the conditions of paragraph (a) 
of this section must also be met for the landing configuration with--
    (1) Maximum available takeoff power initially on each engine;
    (2) The airplane trimmed for an approach, with all engines 
operating, at VREF, at an approach gradient equal to the 
steepest used in the landing distance demonstration of Sec. 23.75;
    (3) Flaps in the landing position;
    (4) Landing gear extended; and
    (5) All propeller controls in the position recommended for approach 
with all engines operating.
    (d) A minimum speed to intentionally render the critical engine 
inoperative must be established and designated as the safe, intentional, 
one-engine-inoperative speed, VSSE.
    (e) At VMC, the rudder pedal force required to maintain 
control must not exceed 150 pounds and it must not be necessary to 
reduce power of the operative engine(s). During the maneuver, the 
airplane must not assume any dangerous attitude and it must be possible 
to prevent a heading change of more than 20 degrees.
    (f) At the option of the applicant, to comply with the requirements 
of Sec. 23.51(c)(1), VMCG may be determined. VMCG 
is the minimum control speed on the ground, and is the calibrated 
airspeed during the takeoff run at which, when the critical engine is 
suddenly made inoperative, it is possible to maintain control of the 
airplane using the rudder control alone (without the use of nosewheel 
steering), as limited by 150 pounds of force, and using the lateral 
control to the extent of keeping the wings level to enable the takeoff 
to be safely continued. In the determination of VMCG, 
assuming that the path of the airplane accelerating with all engines 
operating is along the centerline of the runway, its path from the point 
at which the critical engine is made inoperative to the point at which 
recovery to a direction parallel to the centerline is completed may not 
deviate more than 30 feet laterally from the

[[Page 189]]

centerline at any point. VMCG must be established with--
    (1) The airplane in each takeoff configuration or, at the option of 
the applicant, in the most critical takeoff configuration;
    (2) Maximum available takeoff power on the operating engines;
    (3) The most unfavorable center of gravity;
    (4) The airplane trimmed for takeoff; and
    (5) The most unfavorable weight in the range of takeoff weights.

[Doc. No. 27807, 61 FR 5189, Feb. 9, 1996]