400
14 CFR Ch. I (1–1–14 Edition)
§ 25.333
§ 25.333(b)) and the cockpit pitch con-
trol is suddenly moved to obtain ex-
treme nose up pitching acceleration. In
defining the tail load, the response of
the airplane must be taken into ac-
count. Airplane loads that occur subse-
quent to the time when normal accel-
eration at the c.g. exceeds the positive
limit maneuvering load factor (at point
A
2
in § 25.333(b)), or the resulting
tailplane normal load reaches its max-
imum, whichever occurs first, need not
be considered.
(2)
Specified control displacement. A
checked maneuver, based on a rational
pitching control motion vs. time pro-
file, must be established in which the
design limit load factor specified in
§ 25.337 will not be exceeded. Unless
lesser values cannot be exceeded, the
airplane response must result in pitch-
ing accelerations not less than the fol-
lowing:
(i) A positive pitching acceleration
(nose up) is assumed to be reached con-
currently with the airplane load factor
of 1.0 (Points A
1
to D
1
, § 25.333(b)). The
positive acceleration must be equal to
at least
39n
v
n 1.5 , Radians/sec.
2
−
(
)
(
)
where—
n is the positive load factor at the speed
under consideration, and V is the air-
plane equivalent speed in knots.
(ii) A negative pitching acceleration
(nose down) is assumed to be reached
concurrently with the positive maneu-
vering load factor (points A
2
to D
2
,
§ 25.333(b)). This negative pitching ac-
celeration must be equal to at least
−
−
(
)
(
)
26n
v
n 1.5 , Radians/sec.
2
where—
n is the positive load factor at the speed
under consideration; and V is the air-
plane equivalent speed in knots.
[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]
§ 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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