Section 25.161

14 CFR Ch. I (1-1-19 Edition)

(4) The most unfavorable weight, or,
at the option of the applicant, as a
function of weight;
(5) For propeller airplanes, the propeller of the more critical inoperative
engine in the position it achieves without pilot action, assuming the engine
fails while at the power or thrust necessary to maintain a three degree approach path angle, and the propeller of
the other inoperative engine feathered;
(6) The power or thrust on the operating engine(s) necessary to maintain
an approach path angle of three degrees when one critical engine is inoperative; and
(7) The power or thrust on the operating engine(s) rapidly changed, immediately after the second critical engine
is made inoperative, from the power or
thrust prescribed in paragraph (g)(6) of
this section to - 
(i) Minimum power or thrust; and
(ii) Go-around power or thrust setting.
(h) In demonstrations of VMCL and
VMCL-2 - 
(1) The rudder force may not exceed
150 pounds;
(2) The airplane may not exhibit hazardous 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 necessary 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 exhibited due to any propeller position
achieved when the engine fails or during 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]

spaschal on DSK3GDR082PROD with CFR

TRIM
Section 25.161 Trim.
(a) General. Each airplane must meet
the trim requirements of this section
after being trimmed, and without further pressure upon, or movement of, ei-

ther the primary controls or their corresponding trim controls by the pilot
or the automatic pilot.
(b) Lateral and directional trim. The
airplane must maintain lateral and directional trim with the most adverse
lateral displacement of the center of
gravity within the relevant operating
limitations, during normally expected
conditions of operation (including operation at any speed from 1.3 VSR1 to
VMO/MMO).
(c) Longitudinal trim. The airplane
must maintain longitudinal trim during - 
(1) A climb with maximum continuous power at a speed not more than
1.3 VSR1, with the landing gear retracted, 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 VSR1, or an approach within the normal range of approach speeds appropriate to the
weight and configuration with power
settings corresponding to a 3 degree
glidepath, whichever is the most severe, with the landing gear extended,
the wing flaps (i) retracted and (ii) extended, and with the most unfavorable
combination of center of gravity position and weight approved for landing;
and
(3) Level flight at any speed from 1.3
VSR1, to VMO/MMO, with the landing gear
and flaps retracted, and from 1.3 VSR1 to
VLE with the landing gear extended.
(d) Longitudinal, directional, and lateral trim. The airplane must maintain
longitudinal, directional, and lateral
trim (and for the lateral trim, the
angle of bank may not exceed five degrees) at 1.3 VSR1 during climbing flight
with - 
(1) The critical engine inoperative;
(2) The remaining engines at maximum continuous power; and
(3) The landing gear and flaps retracted.
(e) Airplanes with four or more engines. Each airplane with four or more
engines must also maintain trim in
rectilinear flight with the most unfavorable center of gravity and at the
climb speed, configuration, and power
required by Section 25.123(a) for the purpose of

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