236 

14 CFR Ch. I (1–1–19 Edition) 

§ 25.333 

t

2

= t

1

+ 

D

t 

t

max

= t

2

+ 

π

/

w

; 

D

t = the minimum period of time necessary 

to allow the prescribed limit load factor 

to be achieved in the initial direction, 
but it need not exceed five seconds (see 
figure below). 

(iv) In cases where the flight deck 

pitch control motion may be affected 
by inputs from systems (for example, 
by a stick pusher that can operate at 
high load factor as well as at 1g), then 
the effects of those systems shall be 
taken into account. 

(v) Airplane loads that occur beyond 

the following times need not be consid-
ered: 

(A) For the nose-up pitching maneu-

ver, the time at which the normal ac-
celeration at the center of gravity goes 
below 0g; 

(B) For the nose-down pitching ma-

neuver, the time at which the normal 
acceleration at the center of gravity 
goes above the positive limit load fac-
tor prescribed in § 25.337; 

(C) t

max.

. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–23, 35 FR 5672, Apr. 8, 
1970; Amdt. 25–46, 43 FR 50594, Oct. 30, 1978; 43 
FR 52495, Nov. 13, 1978; 43 FR 54082, Nov. 20, 
1978; Amdt. 25–72, 55 FR 29775, July 20, 1990; 55 
FR 37607, Sept. 12, 1990; Amdt. 25–86, 61 FR 
5220, Feb. 9, 1996; Amdt. 25–91, 62 FR 40704, 
July 29, 1997; Amdt. 25–141, 79 FR 73466, Dec. 
11, 2014] 

§ 25.333

Flight maneuvering envelope. 

(a) 

General. 

The strength require-

ments must be met at each combina-
tion of airspeed and load factor on and 
within the boundaries of the represent-
ative maneuvering envelope (

V-n 

dia-

gram) of paragraph (b) of this section. 
This envelope must also be used in de-
termining the airplane structural oper-
ating limitations as specified in 
§ 25.1501. 

(b) 

Maneuvering envelope. 

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