[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: 14CFR25.253]

[Page 369-370]
 
                     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.  25.253  High-speed characteristics.

    (a) Speed increase and recovery characteristics. The following speed 
increase and recovery characteristics must be met:
    (1) Operating conditions and characteristics likely to cause 
inadvertent speed increases (including upsets in pitch and roll) must be 
simulated with the airplane trimmed at any likely cruise speed up to 
VMO/MMO. These conditions and characteristics include gust upsets, 
inadvertent control movements, low stick force gradient in relation to 
control friction, passenger movement, leveling off from climb, and 
descent from Mach to airspeed limit altitudes.
    (2) Allowing for pilot reaction time after effective inherent or 
artificial speed warning occurs, it must be shown

[[Page 370]]

that the airplane can be recovered to a normal attitude and its speed 
reduced to VMO/MMO, without-
    (i) Exceptional piloting strength or skill;
    (ii) Exceeding VD/MD, VDF/MDF, or the structural limitations; and
    (iii) Buffeting that would impair the pilot's ability to read the 
instruments or control the airplane for recovery.
    (3) With the airplane trimmed at any speed up to VMO/
MMO, there must be no reversal of the response to control 
input about any axis at any speed up to VDF/MDF. 
Any tendency to pitch, roll, or yaw must be mild and readily 
controllable, using normal piloting techniques. When the airplane is 
trimmed at VMO/MMO, the slope of the elevator 
control force versus speed curve need not be stable at speeds greater 
than VFC/MFC, but there must be a push force at 
all speeds up to VDF/MDF and there must be no 
sudden or excessive reduction of elevator control force as 
VDF/MDF is reached.
    (b) Maximum speed for stability characteristics, VFC/
MFC. VFC/MFC is the maximum speed at 
which the requirements of Sec.  Sec.  25.143(f), 25.147(e), 25.175(b)(1), 
25.177, and 25.181 must be met with flaps and landing gear retracted. It 
may not be less than a speed midway between VMO/
MMO and VDF/MDF, except that for 
altitudes where Mach number is the limiting factor, MFC need 
not exceed the Mach number at which effective speed warning occurs.

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-23, 
35 FR 5671, Apr. 8, 1970; Amdt. 25-54, 45 FR 60172, Sept. 11, 1980; 
Amdt. 25-72, 55 FR 29775, July 20, 1990; Amdt. 25-84, 60 FR 30750, June 
9, 1995]