761
Federal Aviation Administration, DOT
§ 35.34
by the declared environmental condi-
tions, including temperature, electro-
magnetic interference (EMI), high in-
tensity radiated fields (HIRF) and
lightning. The environmental limits to
which the system has been satisfac-
torily validated must be documented in
the appropriate propeller manuals.
(3) A method is provided to indicate
that an operating mode change has oc-
curred if flight crew action is required.
In such an event, operating instruc-
tions must be provided in the appro-
priate manuals.
(b) The propeller control system
must be designed and constructed so
that, in addition to compliance with
§ 35.15:
(1) No single failure or malfunction of
electrical or electronic components in
the control system results in a haz-
ardous propeller effect.
(2) Failures or malfunctions directly
affecting the propeller control system
in a typical airplane, such as struc-
tural failures of attachments to the
control, fire, or overheat, do not lead
to a hazardous propeller effect.
(3) The loss of normal propeller pitch
control does not cause a hazardous pro-
peller effect under the intended oper-
ating conditions.
(4) The failure or corruption of data
or signals shared across propellers does
not cause a hazardous propeller effect.
(c) Electronic propeller control sys-
tem imbedded software must be de-
signed and implemented by a method
approved by the Administrator that is
consistent with the criticality of the
performed functions and that mini-
mizes the existence of software errors.
(d) The propeller control system
must be designed and constructed so
that the failure or corruption of air-
plane-supplied data does not result in
hazardous propeller effects.
(e) The propeller control system
must be designed and constructed so
that the loss, interruption or abnormal
characteristic of airplane-supplied
electrical power does not result in haz-
ardous propeller effects. The power
quality requirements must be described
in the appropriate manuals.
[Amdt. 35–8, 73 FR 63347, Oct. 24, 2008]
§ 35.24
Strength.
The maximum stresses developed in
the propeller may not exceed values ac-
ceptable to the Administrator consid-
ering the particular form of construc-
tion and the most severe operating
conditions.
[Amdt. 35–8, 73 FR 63348, Oct. 24, 2008]
Subpart C—Tests and Inspections
§ 35.31
[Reserved]
§ 35.33
General.
(a) Each applicant must furnish test
article(s) and suitable testing facili-
ties, including equipment and com-
petent personnel, and conduct the re-
quired tests in accordance with part 21
of this chapter.
(b) All automatic controls and safety
systems must be in operation unless it
is accepted by the Administrator as
impossible or not required because of
the nature of the test. If needed for
substantiation, the applicant may test
a different propeller configuration if
this does not constitute a less severe
test.
(c) Any systems or components that
cannot be adequately substantiated by
the applicant to the requirements of
this part are required to undergo addi-
tional tests or analysis to demonstrate
that the systems or components are
able to perform their intended func-
tions in all declared environmental and
operating conditions.
[Amdt. 35–8, 73 FR 63348, Oct. 24, 2008]
§ 35.34
Inspections, adjustments and
repairs.
(a) Before and after conducting the
tests prescribed in this part, the test
article must be subjected to an inspec-
tion, and a record must be made of all
the relevant parameters, calibrations
and settings.
(b) During all tests, only servicing
and minor repairs are permitted. If
major repairs or part replacement is
required, the Administrator must ap-
prove the repair or part replacement
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14 CFR Ch. I (1–1–24 Edition)
§ 35.35
prior to implementation and may re-
quire additional testing. Any unsched-
uled repair or action on the test article
must be recorded and reported.
[Amdt. 35–8, 73 FR 63348, Oct. 24, 2008]
§ 35.35
Centrifugal load tests.
The applicant must demonstrate that
a propeller complies with paragraphs
(a), (b) and (c) of this section without
evidence of failure, malfunction, or
permanent deformation that would re-
sult in a major or hazardous propeller
effect. When the propeller could be sen-
sitive to environmental degradation in
service, this must be considered. This
section does not apply to fixed-pitch
wood or fixed-pitch metal propellers of
conventional design.
(a) The hub, blade retention system,
and counterweights must be tested for
a period of one hour to a load equiva-
lent to twice the maximum centrifugal
load to which the propeller would be
subjected during operation at the max-
imum rated rotational speed.
(b) Blade features associated with
transitions to the retention system (for
example, a composite blade bonded to a
metallic retention) must be tested ei-
ther during the test of paragraph (a) of
this section or in a separate component
test for a period of one hour to a load
equivalent to twice the maximum cen-
trifugal load to which the propeller
would be subjected during operation at
the maximum rated rotational speed.
(c) Components used with or attached
to the propeller (for example, spinners,
de-icing equipment, and blade erosion
shields) must be subjected to a load
equivalent to 159 percent of the max-
imum centrifugal load to which the
component would be subjected during
operation at the maximum rated rota-
tional speed. This must be performed
by either:
(1) Testing at the required load for a
period of 30 minutes; or
(2) Analysis based on test.
[Amdt. 35–8, 73 FR 63348, Oct. 24, 2008]
§ 35.36
Bird impact.
The applicant must demonstrate, by
tests or analysis based on tests or expe-
rience on similar designs, that the pro-
peller can withstand the impact of a 4-
pound bird at the critical location(s)
and critical flight condition(s) of a typ-
ical installation without causing a
major or hazardous propeller effect.
This section does not apply to fixed-
pitch wood propellers of conventional
design.
[Amdt. 35–8, 73 FR 63348, Oct. 24, 2008]
§ 35.37
Fatigue limits and evaluation.
This section does not apply to fixed-
pitch wood propellers of conventional
design.
(a) Fatigue limits must be estab-
lished by tests, or analysis based on
tests, for propeller:
(1) Hubs.
(2) Blades.
(3) Blade retention components.
(4) Components which are affected by
fatigue loads and which are shown
under § 35.15 to have a fatigue failure
mode leading to hazardous propeller ef-
fects.
(b) The fatigue limits must take into
account:
(1) All known and reasonably foresee-
able vibration and cyclic load patterns
that are expected in service; and
(2) Expected service deterioration,
variations in material properties, man-
ufacturing variations, and environ-
mental effects.
(c) A fatigue evaluation of the pro-
peller must be conducted to show that
hazardous propeller effects due to fa-
tigue will be avoided throughout the
intended operational life of the pro-
peller on either:
(1) The intended airplane by com-
plying with § 23.2400(c) or § 25.907 of this
chapter, as applicable; or
(2) A typical airplane.
[Amdt. 35–8, 73 FR 63348, Oct. 24, 2008, as
amended by Doc. FAA–2015–1621, Amdt. 35–10,
81 FR 96700, Dec. 30, 2016]
§ 35.38
Lightning strike.
The applicant must demonstrate, by
tests, analysis based on tests, or expe-
rience on similar designs, that the pro-
peller can withstand a lightning strike
without causing a major or hazardous
propeller effect. The limit to which the
propeller has been qualified must be
documented in the appropriate manu-
als. This section does not apply to
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