[Code of Federal Regulations]
[Title 14, Volume 1]
[Revised as of January 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 14CFR25.177]

[Page 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. 25.177  Static lateral-directional stability.

    (a)-(b) [Reserved]
    (c) In straight, steady sideslips, the aileron and rudder control 
movements and forces must be substantially proportional to the angle of 
sideslip in a stable sense; and the factor of proportionality must lie 
between limits found necessary for safe operation throughout the range 
of sideslip angles appropriate to the operation of the airplane. At 
greater angles, up to the angle at which full rudder is used or a rudder 
force of 180 pounds is obtained, the rudder pedal forces may not 
reverse; and increased rudder deflection must be needed for increased 
angles of sideslip. Compliance with this paragraph must be demonstrated 
for all landing gear and flap positions and symmetrical power conditions 
at speeds from 1.13 VSR1 to VFE, VLE, 
or VFC/MFC, as appropriate.
    (d) The rudder gradients must meet the requirements of paragraph (c) 
at speeds between VMO/MMO and VFC/
MFC except that the dihedral effect (aileron deflection 
opposite the corresponding rudder input) may be negative provided the 
divergence is gradual, easily recognized, and easily controlled by the 
pilot.

[Amdt. 25-72, 55 FR 29774, July 20, 1990; 55 FR 37607, Sept. 12, 1990; 
Amdt. 25-108, 67 FR 70827, Nov. 26, 2002]