Code of Federal Regulations - Title 14

177

Federal Aviation Administration, DOT

Pt. 23, SFAR No. 23

maintain trim at a speed greater than

MO™

(1) In the approach conditions specified in

FAR 23.161(c)(3) through (5), except that in-
stead of the speeds specified therein, trim
must be maintained with a stick force of not
more than 10 pounds down to a speed used in
showing compliance with section 7 of this
regulation or 1.4

whichever is lower.

(2) In level flight at any speed from

MO,

whichever is lower, to either

Vx or

1.4

, with the landing gear and wing flaps

retracted.

TABILITY

Static longitudinal stability. (a) In showing

compliance with the provisions of FAR
23.175(b) and with paragraph (b) of this sec-
tion, the airspeed must return to within

⁄

percent of the trim speed.

(b)

Cruise stability. The stick force curve

must have a stable slope for a speed range of

50 knots from the trim speed except that

the speeds need not exceed

or be

less than 1.4

. This speed range will be

considered to begin at the outer extremes of
the friction band and the stick force may not
exceed 50 pounds with—

(i) Landing gear retracted;
(ii) Wing flaps retracted;
(iii) The maximum cruising power as se-

lected by the applicant as an operating limi-
tation for turbine engines or 75 percent of
maximum continuous power for recipro-
cating engines except that the power need
not exceed that required at

MO™

(iv) Maximum takeoff weight; and
(v) The airplane trimmed for level flight

with the power specified in subparagraph
(iii) of this paragraph.

may not be less than a speed mid-

way between

and

DF,

except

that, for altitudes where Mach number is the
limiting factor,

need not exceed the

Mach number at which effective speed warn-
ing occurs.

(c)

Climb stability. For turbopropeller powered

airplanes only. In showing compliance with
FAR 23.175(a), an applicant must in lieu of
the power specified in FAR 23.175(a)(4), use
the maximum power or thrust selected by
the applicant as an operating limitation for
use during climb at the best rate of climb
speed except that the speed need not be less
than 1.4

TALLS

10.

Stall warning. If artificial stall warning

is required to comply with the requirements
of FAR 23.207, the warning device must give
clearly distinguishable indications under ex-
pected conditions of flight. The use of a vis-
ual warning device that requires the atten-
tion of the crew within the cockpit is not ac-
ceptable by itself.

ONTROL

YSTEMS

11.

Electric trim tabs. The airplane must

meet the requirements of FAR 23.677 and in
addition it must be shown that the airplane
is safely controllable and that a pilot can
perform all the maneuvers and operations
necessary to effect a safe landing following
any probable electric trim tab runaway
which might be reasonably expected in serv-
ice allowing for appropriate time delay after
pilot recognition of the runaway. This dem-
onstration must be conducted at the critical
airplane weights and center of gravity posi-
tions.

NSTRUMENTS

: I

NSTALLATION

12.

Arrangement and visibility. Each instru-

ment must meet the requirements of FAR
23.1321 and in addition—

(a) Each flight, navigation, and powerplant

instrument for use by any pilot must be
plainly visible to him from his station with
the minimum practicable deviation from his
normal position and line of vision when he is
looking forward along the flight path.

(b) The flight instruments required by FAR

23.1303 and by the applicable operating rules
must be grouped on the instrument panel
and centered as nearly as practicable about
the vertical plane of each pilot’s forward vi-
sion. In addition—

(1) The instrument that most effectively

indicates the attitude must be on the panel
in the top center position;

(2) The instrument that most effectively

indicates airspeed must be adjacent to and
directly to the left of the instrument in the
top center position;

(3) The instrument that most effectively

indicates altitude must be adjacent to and
directly to the right of the instrument in the
top center position; and

(4) The instrument that most effectively

indicates direction of flight must be adjacent
to and directly below the instrument in the
top center position.

13.

Airspeed indicating system. Each airspeed

indicating system must meet the require-
ments of FAR 23.1323 and in addition—

(a) Airspeed indicating instruments must

be of an approved type and must be cali-
brated to indicate true airspeed at sea level
in the standard atmosphere with a
mimimum practicable instrument calibra-
tion error when the corresponding pilot and
static pressures are supplied to the instru-
ments.

(b) The airspeed indicating system must be

calibrated to determine the system error,
i.e., the relation between IAS and CAS, in
flight and during the accelerate takeoff
ground run. The ground run calibration must
be obtained between 0.8 of the mimimum
value of

and 1.2 times the maximum value

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