[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: 14CFR23.177]



[Page 198]

 

                     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. 23.177  Static directional and lateral stability.



    (a) The static directional stability, as shown by the tendency to 

recover from a wings level sideslip with the rudder free, must be 

positive for any landing gear and flap position appropriate to the 

takeoff, climb, cruise, approach, and landing configurations. This must 

be shown with symmetrical power up to maximum continuous power, and at 

speeds from 1.2 VS1 up to the maximum allowable speed for the 

condition being investigated. The angel of sideslip for these tests must 

be appropriate to the type of airplane. At larger angles of sideslip, up 

to that at which full rudder is used or a control force limit in Sec. 

23.143 is reached, whichever occurs first, and at speeds from 1.2 

VS1 to VO, the rudder pedal force must not 

reverse.

    (b) The static lateral stability, as shown by the tendency to raise 

the low wing in a sideslip, must be positive for all landing gear and 

flap positions. This must be shown with symmetrical power up to 75 

percent of maximum continuous power at speeds above 1.2 VS1 

in the take off configuration(s) and at speeds above 1.3 VS1 

in other configurations, up to the maximum allowable speed for the 

configuration being investigated, in the takeoff, climb, cruise, and 

approach configurations. For the landing configuration, the power must 

be that necessary to maintain a 3 degree angle of descent in coordinated 

flight. The static lateral stability must not be negative at 1.2 

VS1 in the takeoff configuration, or at 1.3 VS1 in 

other configurations. The angle of sideslip for these tests must be 

appropriate to the type of airplane, but in no case may the constant 

heading sideslip angle be less than that obtainable with a 10 degree 

bank, or if less, the maximum bank angle obtainable with full rudder 

deflection or 150 pound rudder force.

    (c) Paragraph (b) of this section does not apply to acrobatic 

category airplanes certificated for inverted flight.

    (d) In straight, steady slips at 1.2 VS1 for any landing 

gear and flap positions, and for any symmetrical power conditions up to 

50 percent of maximum continuous power, the aileron and rudder control 

movements and forces must increase steadily, but not necessarily in 

constant proportion, as the angle of sideslip is increased up to the 

maximum appropriate to the type of airplane. At larger slip angles, up 

to the angle at which full rudder or aileron control is used or a 

control force limit contained in Sec. 23.143 is reached, the aileron 

and rudder control movements and forces must not reverse as the angle of 

sideslip is increased. Rapid entry into, and recovery from, a maximum 

sideslip considered appropriate for the airplane must not result in 

uncontrollable flight characteristics.



[Doc. No. 27807, 61 FR 5190, Feb. 9, 1996]