[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: 14CFR23.175]

[Page 200]
 
                     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.  23.175  Demonstration of static longitudinal stability.

    Static longitudinal stability must be shown as follows:
    (a) Climb. The stick force curve must have a stable slope at speeds 
between 85 and 115 percent of the trim speed, with--
    (1) Flaps retracted;
    (2) Landing gear retracted;
    (3) Maximum continuous power; and
    (4) The airplane trimmed at the speed used in determining the climb 
performance required by Sec.  23.69(a).
    (b) Cruise. With flaps and landing gear retracted and the airplane 
in trim with power for level flight at representative cruising speeds at 
high and low altitudes, including speeds up to VNO or 
VMO/MMO, as appropriate, except that the speed 
need not exceed VH--
    (1) For normal, utility, and acrobatic category airplanes, the stick 
force curve must have a stable slope at all speeds within a range that 
is the greater of 15 percent of the trim speed plus the resulting free 
return speed range, or 40 knots plus the resulting free return speed 
range, above and below the trim speed, except that the slope need not be 
stable--
    (i) At speeds less than 1.3 VS1; or
    (ii) For airplanes with VNE established under Sec.  
23.1505(a), at speeds greater than VNE; or
    (iii) For airplanes with VMO/MMO established 
under Sec.  23.1505(c), at speeds greater than VFC/
MFC.
    (2) For commuter category airplanes, the stick force curve must have 
a stable slope at all speeds within a range of 50 knots plus the 
resulting free return speed range, above and below the trim speed, 
except that the slope need not be stable--
    (i) At speeds less than 1.4 VS1; or
    (ii) At speeds greater than VFC/MFC; or
    (iii) At speeds that require a stick force greater than 50 pounds.
    (c) Landing. The stick force curve must have a stable slope at 
speeds between 1.1 VS1 and 1.8 VS1 with--
    (1) Flaps in the landing position;
    (2) Landing gear extended; and
    (3) The airplane trimmed at--
    (i) VREF, or the minimum trim speed if higher, with power 
off; and
    (ii) VREF with enough power to maintain a 3 degree angle 
of descent.

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