Code of Federal Regulations - Title 14

180

14 CFR Ch. I (1–1–14 Edition)

Pt. 23, SFAR No. 23

need not exceed the maximum vertical load
in paragraph (c)(1) of this section.

ATIGUE

VALUATION

28.

Fatigue evaluation of wing and associated

structure. Unless it is shown that the struc-
ture, operating stress levels, materials, and
expected use are comparable from a fatigue
standpoint to a similar design which has had
substantial satisfactory service experience,
the strength, detail design, and the fabrica-
tion of those parts of the wing, wing carry-
through, and attaching structure whose fail-
ure would be catastrophic must be evaluated
under either—

(a) A fatigue strength investigation in

which the structure is shown by analysis,
tests, or both to be able to withstand the re-
peated loads of variable magnitude expected
in service; or

(b) A fail-safe strength investigation in

which it is shown by analysis, tests, or both
that catastrophic failure of the structure is
not probable after fatigue, or obvious partial
failure, of a principal structural element,
and that the remaining structure is able to
withstand a static ultimate load factor of 75
percent of the critical limit load factor at

These loads must be multiplied by a factor of
1.15 unless the dynamic effects of failure
under static load are otherwise considered.

ESIGN AND

ONSTRUCTION

29.

Flutter. For Multiengine turbopropeller

powered airplanes, a dynamic evaluation
must be made and must include—

(a) The significant elastic, inertia, and aer-

odynamic forces associated with the rota-
tions and displacements of the plane of the
propeller; and

(b) Engine-propeller-nacelle stiffness and

damping variations appropriate to the par-
ticular configuration.

ANDING

EAR

30.

Flap operated landing gear warning de-

vice. Airplanes having retractable landing
gear and wing flaps must be equipped with a
warning device that functions continuously
when the wing flaps are extended to a flap
position that activates the warning device to
give adequate warning before landing, using
normal landing procedures, if the landing
gear is not fully extended and locked. There
may not be a manual shut off for this warn-
ing device. The flap position sensing unit
may be installed at any suitable location.
The system for this device may use any part
of the system (including the aural warning
device) provided for other landing gear warn-
ing devices.

ERSONNEL AND

ARGO

CCOMMODATIONS

31.

Cargo and baggage compartments. Cargo

and baggage compartments must be designed
to meet the requirements of FAR 23.787 (a)

and (b), and in addition means must be pro-
vided to protect passengers from injury by
the contents of any cargo or baggage com-
partment when the ultimate forward inertia
force is 9

32.

Doors and exits. The airplane must meet

the requirements of FAR 23.783 and FAR
23.807 (a)(3), (b), and (c), and in addition:

(a) There must be a means to lock and

safeguard each external door and exit
against opening in flight either inadvert-
ently by persons, or as a result of mechan-
ical failure. Each external door must be op-
erable from both the inside and the outside.

(b) There must be means for direct visual

inspection of the locking mechanism by
crewmembers to determine whether external
doors and exits, for which the initial opening
movement is outward, are fully locked. In
addition, there must be a visual means to
signal to crewmembers when normally used
external doors are closed and fully locked.

ify as a floor level emergency exit. Each ad-
ditional required emergency exit except floor
level exits must be located over the wing or
must be provided with acceptable means to
assist the occupants in descending to the
ground. In addition to the passenger en-
trance door:

(1) For a total seating capacity of 15 or

less, an emergency exit as defined in FAR
23.807(b) is required on each side of the cabin.

(2) For a total seating capacity of 16

through 23, three emergency exits as defined
in 23.807(b) are required with one on the same
side as the door and two on the side opposite
the door.

(d) An evacuation demonstration must be

conducted utilizing the maximum number of
occupants for which certification is desired.
It must be conducted under simulated night
conditions utilizing only the emergency
exits on the most critical side of the aircraft.
The participants must be representative of
average airline passengers with no prior
practice or rehearsal for the demonstration.
Evacuation must be completed within 90 sec-
onds.

(e) Each emergency exit must be marked

with the word ‘‘Exit’’ by a sign which has
white letters 1 inch high on a red back-
ground 2 inches high, be self-illuminated or
independently internally electrically illumi-
nated, and have a minimum luminescence
(brightness) of at least 160 microlamberts.
The colors may be reversed if the passenger
compartment illumination is essentially the
same.

(f) Access to window type emergency exits

must not be obstructed by seats or seat
backs.

(g) The width of the main passenger aisle

at any point between seats must equal or ex-
ceed the values in the following table.

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