[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: 14CFR23.149]



[Page 194-195]

 

                     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 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



[[Page 195]]



    (5) The most unfavorable weight in the range of takeoff weights.



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