[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: 14CFR25.251]



[Page 367]

 

                     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. 25.251  Vibration and buffeting.



    (a) The airplane must be demonstrated in flight to be free from any 

vibration and buffeting that would prevent continued safe flight in any 

likely operating condition.

    (b) Each part of the airplane must be demonstrated in flight to be 

free from excessive vibration under any appropriate speed and power 

conditions up to VDF/MDF. The maximum speeds shown 

must be used in establishing the operating limitations of the airplane 

in accordance with Sec. 25.1505.

    (c) Except as provided in paragraph (d) of this section, there may 

be no buffeting condition, in normal flight, including configuration 

changes during cruise, severe enough to interfere with the control of 

the airplane, to cause excessive fatigue to the crew, or to cause 

structural damage. Stall warning buffeting within these limits is 

allowable.

    (d) There may be no perceptible buffeting condition in the cruise 

configuration in straight flight at any speed up to VMO/MMO, except that 

stall warning buffeting is allowable.

    (e) For an airplane with MD greater than .6 or with a 

maximum operating altitude greater than 25,000 feet, the positive 

maneuvering load factors at which the onset of perceptible buffeting 

occurs must be determined with the airplane in the cruise configuration 

for the ranges of airspeed or Mach number, weight, and altitude for 

which the airplane is to be certificated. The envelopes of load factor, 

speed, altitude, and weight must provide a sufficient range of speeds 

and load factors for normal operations. Probable inadvertent excursions 

beyond the boundaries of the buffet onset envelopes may not result in 

unsafe conditions.



[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as amended by Amdt. 25-23, 

35 FR 5671, Apr. 8, 1970; Amdt. 25-72, 55 FR 29775, July 20, 1990; Amdt. 

25-77, 57 FR 28949, June 29, 1992]