660
14 CFR Ch. I (1–1–14 Edition)
§ 27.601
Subpart D—Design and
Construction
G
ENERAL
§ 27.601
Design.
(a) The rotorcraft may have no de-
sign features or details that experience
has shown to be hazardous or unreli-
able.
(b) The suitability of each question-
able design detail and part must be es-
tablished by tests.
§ 27.602
Critical parts.
(a)
Critical part. A critical part is a
part, the failure of which could have a
catastrophic effect upon the rotocraft,
and for which critical characteristics
have been identified which must be
controlled to ensure the required level
of integrity.
(b) If the type design includes crtical
parts, a critical parts list shall be es-
tablished. Procedures shall be estab-
lished to define the critical design
characteristics, identify processes that
affect those characteristics, and iden-
tify the design change and process
change controls necessary for showing
compliance with the quality assurance
requirements of part 21 of this chapter.
[Doc. No. 29311, 64 FR 46232, Aug. 24, 1999]
§ 27.603
Materials.
The suitability and durability of ma-
terials used for parts, the failure of
which could adversely affect safety,
must—
(a) Be established on the basis of ex-
perience or tests;
(b) Meet approved specifications that
ensure their having the strength and
other properties assumed in the design
data; and
(c) Take into account the effects of
environmental conditions, such as tem-
perature and humidity, expected in
service.
(Secs. 313(a), 601, 603, 604, Federal Aviation
Act of 1958 (49 U.S.C. 1354(a), 1421, 1423, 1424);
and sec. 6(c) of the Dept. of Transportation
Act (49 U.S.C. 1655(c)))
[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as
amended by Amdt. 27–11, 41 FR 55469, Dec. 20,
1976; Amdt. 27–16, 43 FR 50599, Oct. 30, 1978]
§ 27.605
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
according to an approved process speci-
fication.
(b) Each new aircraft fabrication
method must be substantiated by a
test program.
(Secs. 313(a), 601, 603, 604, and 605 of the Fed-
eral Aviation Act of 1958 (49 U.S.C. 1354(a),
1421, 1423, 1424 and 1425); sec. 6(c) of the Dept.
of Transportation Act (49 U.S.C. 1655(c)))
[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as
amended by Amdt. 27–16, 43 FR 50599, Oct. 30,
1978]
§ 27.607
Fasteners.
(a) Each removable bolt, screw, nut,
pin, or other fastener whose loss could
jeopardize the safe operation of the
rotorcraft must incorporate two sepa-
rate locking devices. The fastener and
its locking devices may not be ad-
versely affected by the environmental
conditions associated with the par-
ticular installation.
(b) No self-locking nut may be used
on any bolt subject to rotation in oper-
ation unless a nonfriction locking de-
vice is used in addition to the self-lock-
ing device.
[Amdt. 27–4, 33 FR 14533, Sept. 27, 1968]
§ 27.609
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 provisions for ventilation
and drainage where necessary to pre-
vent the accumulation of corrosive,
flammable, or noxious fluids.
§ 27.610
Lightning and static elec-
tricity protection.
(a) The rotorcraft must be protected
against catastrophic effects from light-
ning.
(b) For metallic components, compli-
ance with paragraph (a) of this section
may be shown by—
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