Code of Federal Regulations - Title 14

904

14 CFR Ch. I (1–1–14 Edition)

§ 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.

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 § 23.907 or § 25.907 of this
chapter, as applicable; or

(2) A typical airplane.

[Amdt. 35–8, 73 FR 63348, Oct. 24, 2008]

§ 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
fixed-pitch wood propellers of conven-
tional design.

[Amdt. 35–8, 73 FR 63348, Oct. 24, 2008]

§ 35.39

Endurance test.

Endurance tests on the propeller sys-

tem must be made on a representative
engine in accordance with paragraph
(a) or (b) of this section, as applicable,
without evidence of failure or malfunc-
tion.

(a) Fixed-pitch and ground adjust-

able-pitch propellers must be subjected
to one of the following tests:

(1) A 50-hour flight test in level flight

or in climb. The propeller must be op-
erated at takeoff power and rated rota-
tional speed during at least five hours
of this flight test, and at not less than
90 percent of the rated rotational speed
for the remainder of the 50 hours.

(2) A 50-hour ground test at takeoff

power and rated rotational speed.

(b) Variable-pitch propellers must be

subjected to one of the following tests:

(1) A 110-hour endurance test that

must include the following conditions:

(i) Five hours at takeoff power and

rotational speed and thirty 10-minute
cycles composed of:

(A) Acceleration from idle,
(B) Five minutes at takeoff power

and rotational speed,

uous power and rotational speed,

(iii) Fifty hours, consisting of ten 5-

hour cycles composed of:

(A) Five accelerations and decelera-

tions between idle and takeoff power
and rotational speed,

(B) Four and one half hours at ap-

proximately even incremental condi-
tions from idle up to, but not includ-
ing, maximum continuous power and
rotational speed, and

throughout the engine endurance tests
prescribed in part 33 of this chapter.

pellers of similar design may be used in
place of the tests of paragraphs (a) and
(b) of this section.

[Amdt. 35–8, 73 FR 63348, Oct. 24, 2008]

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