Code of Federal Regulations - Title 14

236

14 CFR Ch. I (1–1–14 Edition)

§ 23.575

(a)

Metallic damage tolerance. An eval-

uation of the strength, detail design,
and fabrication must show that cata-
strophic failure due to fatigue, corro-
sion, defects, or damage will be avoided
throughout the operational life of the
airplane. This evaluation must be con-
ducted in accordance with the provi-
sions of § 23.573, except as specified in
paragraph (b) of this section, for each
part of the structure that could con-
tribute to a catastrophic failure.

(b)

Fatigue (safe-life) evaluation. Com-

pliance with the damage tolerance re-
quirements of paragraph (a) of this sec-
tion is not required if the applicant es-
tablishes that the application of those
requirements is impractical for a par-
ticular structure. This structure must
be shown, by analysis supported by test
evidence, to be able to withstand the
repeated loads of variable magnitude
expected during its service life without
detectable cracks. Appropriate safe-life
scatter factors must be applied.

[Doc. No. 27805, 61 FR 5148, Feb. 9, 1996]

§ 23.575

Inspections and other proce-

dures.

Each inspection or other procedure,

based on an evaluation required by
§§ 23.571, 23.572, 23.573 or 23.574, must be
established to prevent catastrophic
failure and must be included in the
Limitations Section of the Instructions
for Continued Airworthiness required
by § 23.1529.

[Doc. No. 27805, 61 FR 5148, Feb. 9, 1996]

Subpart D—Design and

Construction

§ 23.601

General.

The suitability of each questionable

design detail and part having an impor-
tant bearing on safety in operations,
must be established by tests.

§ 23.603

Materials and workmanship.

(a) The suitability and durability of

materials used for parts, the failure of
which could adversely affect safety,
must—

(1) Be established by experience or

tests;

(2) Meet approved specifications that

ensure their having the strength and

other properties assumed in the design
data; and

(3) Take into account the effects of

environmental conditions, such as tem-
perature and humidity, expected in
service.

(b) Workmanship must be of a high

standard.

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as
amended by Amdt. 23–17, 41 FR 55464, Dec. 20,
1976; Amdt. 23–23, 43 FR 50592, Oct. 10, 1978]

§ 23.605

Fabrication methods.

(a) The methods of fabrication used

must produce consistently sound struc-
tures. If a fabrication process (such as
gluing, spot welding, or heat-treating)
requires close control to reach this ob-
jective, the process must be performed
under an approved process specifica-
tion.

(b) Each new aircraft fabrication

method must be substantiated by a
test program.

[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964; 30
FR 258, Jan. 9, 1965, as amended by Amdt. 23–
23, 43 FR 50592, Oct. 10, 1978]

§ 23.607

Fasteners.

(a) Each removable fastener must in-

corporate two retaining devices if the
loss of such fastener would preclude
continued safe flight and landing.

(b) Fasteners and their locking de-

vices must not be adversely affected by
the environmental conditions associ-
ated with the particular installation.

on any bolt subject to rotation in oper-
ation unless a non-friction locking de-
vice is used in addition to the self-lock-
ing device.

[Doc. No. 27805, 61 FR 5148, Feb. 9, 1996]

§ 23.609

Protection of structure.

Each part of the structure must—
(a) Be suitably protected against de-

terioration or loss of strength in serv-
ice due to any cause, including—

(1) Weathering;
(2) Corrosion; and
(3) Abrasion; and
(b) Have adequate provisions for ven-

tilation and drainage.

§ 23.611

Accessibility provisions.

For each part that requires mainte-

nance, inspection, or other servicing,

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