389
Federal Aviation Administration, DOT
§ 25.171
(h) In demonstrations of V
MCL
and
V
MCL-2
—
(1) The rudder force may not exceed
150 pounds;
(2) The airplane may not exhibit haz-
ardous flight characteristics or require
exceptional piloting skill, alertness, or
strength;
(3) Lateral control must be sufficient
to roll the airplane, from an initial
condition of steady flight, through an
angle of 20 degrees in the direction nec-
essary to initiate a turn away from the
inoperative engine(s), in not more than
5 seconds; and
(4) For propeller airplanes, hazardous
flight characteristics must not be ex-
hibited due to any propeller position
achieved when the engine fails or dur-
ing any likely subsequent movements
of the engine or propeller controls.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25–42, 43 FR 2321, Jan. 16,
1978; Amdt. 25–72, 55 FR 29774, July 20, 1990; 55
FR 37607, Sept. 12, 1990; Amdt. 25–84, 60 FR
30749, June 9, 1995; Amdt. 25–108, 67 FR 70827,
Nov. 26, 2002]
T
RIM
§ 25.161
Trim.
(a)
General. Each airplane must meet
the trim requirements of this section
after being trimmed, and without fur-
ther pressure upon, or movement of, ei-
ther the primary controls or their cor-
responding trim controls by the pilot
or the automatic pilot.
(b)
Lateral and directional trim. The
airplane must maintain lateral and di-
rectional trim with the most adverse
lateral displacement of the center of
gravity within the relevant operating
limitations, during normally expected
conditions of operation (including op-
eration at any speed from 1.3
V
SR1
to
V
MO
/M
MO
).
(c)
Longitudinal trim. The airplane
must maintain longitudinal trim dur-
ing—
(1) A climb with maximum contin-
uous power at a speed not more than
1.3
V
SR1
, with the landing gear re-
tracted, and the flaps (i) retracted and
(ii) in the takeoff position;
(2) Either a glide with power off at a
speed not more than 1.3 V
SR1
, or an ap-
proach within the normal range of ap-
proach speeds appropriate to the
weight and configuration with power
settings corresponding to a 3 degree
glidepath, whichever is the most se-
vere, with the landing gear extended,
the wing flaps (i) retracted and (ii) ex-
tended, and with the most unfavorable
combination of center of gravity posi-
tion and weight approved for landing;
and
(3) Level flight at any speed from 1.3
V
SR1
, to
V
MO
/M
MO,
with the landing gear
and flaps retracted, and from 1.3
V
SR1
to
V
LE
with the landing gear extended.
(d)
Longitudinal, directional, and lat-
eral trim. The airplane must maintain
longitudinal, directional, and lateral
trim (and for the lateral trim, the
angle of bank may not exceed five de-
grees) at 1.3
V
SR1
during climbing flight
with—
(1) The critical engine inoperative;
(2) The remaining engines at max-
imum continuous power; and
(3) The landing gear and flaps re-
tracted.
(e) Airplanes with four or more en-
gines. Each airplane with four or more
engines must also maintain trim in
rectilinear flight with the most unfa-
vorable center of gravity and at the
climb speed, configuration, and power
required by § 25.123(a) for the purpose of
establishing the en route flight paths
with two engines inoperative.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25–23, 35 FR 5671, Apr. 8,
1970; Amdt. 25–38, 41 FR 55466, Dec. 20, 1976;
Amdt. 25–108, 67 FR 70827, Nov. 26, 2002;
Amdt. 25–115, 69 FR 40527, July 2, 2004]
S
TABILITY
§ 25.171
General.
The airplane must be longitudinally,
directionally, and laterally stable in
accordance with the provisions of
§§ 25.173 through 25.177. In addition,
suitable stability and control feel
(static stability) is required in any con-
dition normally encountered in service,
if flight tests show it is necessary for
safe operation.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25–7, 30 FR 13117, Oct. 15,
1965]
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