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(a)
This part prescribes airworthiness standards for the
issue of type certificates and changes to those
certificates, for propellers.
(b)
Each person who applies under Part 21 for such a
certificate or change must show compliance with the
applicable requirements of this part.
Each
applicant must prepare and make available an
approved manual or manuals containing instructions
for installing and operating the propeller.
35.4 Instructions for Continued Airworthiness.
The
applicant must prepare Instructions for Continued
Airworthiness in accordance with appendix A to this
part that are acceptable to the Administrator. The
instructions may be incomplete at type certification
if a program exists to ensure their completion prior
to delivery of the first aircraft with the propeller
installed, or upon issuance of a standard
certificate of airworthiness for an aircraft with
the propeller installed, whichever occurs later.
Propeller operating limitations are established by
the Administrator, are included in the propeller
type certificate data sheet specified in 21.41 of
this chapter, and include limitations based on the
operating conditions demonstrated during the tests
required by this part and any other information
found necessary for the safe operation of the
propeller.
This
subpart prescribes the design and construction
requirements for propellers.
Each
applicant must show that the propeller concerned
meets the design and construction requirements of
this subpart.
The
propeller may not have design features that
experience has shown to be hazardous or unreliable.
The suitability of each questionable design detail
or part must be established by tests.
The
suitability and durability of materials used in the
propeller must—
(a)
Be established on the basis of experience or tests;
and
(b)
Conform to approved specifications (such as industry
or military specifications, or Technical Standard
Orders) that ensure their having the strength and
other properties assumed in the design data.
Each
part of the propeller must be designed and
constructed to minimize the development of any
unsafe condition of the propeller between overhaul
periods.
A
reversible propeller must be adaptable for use with
a reversing system in an airplane so that no single
failure or malfunction in that system during normal
or emergency operation will result in unwanted
travel of the propeller blades to a position
substantially below the normal flight low-pitch
stop. Failure of structural elements need not be
considered if the occurrence of such a failure is
expected to be extremely remote. For the purposes of
this section the term “reversing system” means that
part of the complete reversing system that is in the
propeller itself and those other parts that are
supplied by the applicant for installation in the
aircraft.
(a)
No loss of normal propeller pitch control may cause
hazardous over speeding of the propeller under
intended operating conditions.
(b)
Each pitch control system that is within the
propeller, or supplied with the propeller, and that
uses engine oil for feathering, must incorporate
means to override or bypass the normally operative
hydraulic system components so as to allow
feathering if those components fail or malfunction.
(c)
Each propeller approved for installation on a
turbopropeller engine must incorporate a provision
for an indicator to indicate when the propeller
blade angle is below the flight low pitch position.
The provision must directly sense the blade position
and be arranged to cause an indicator to indicate
that the blade angle is below the flight low pitch
position before the blade moves more than 8° below
the flight low pitch stop.
This
subpart prescribes the tests and inspections for
propellers and their essential accessories.
(a)
Each applicant must show that the propeller
concerned and its essential accessories complete the
tests and inspections of this subpart without
evidence of failure or malfunction.
(b)
Each applicant must furnish testing facilities,
including equipment, and competent personnel, to
conduct the required tests.
The
hub and blade retention arrangement of propellers
with detachable blades must be subjected to a
centrifugal load of twice the maximum centrifugal
force to which the propeller would be subjected
during operations within the limitations established
for the propeller. This may be done by either a
whirl test or a static pull test.
35.37 Fatigue limit tests.
A
fatigue evalution must be made and the fatigue
limits determined for each metallic hub and blade,
and each primary load carrying metal component of
nonmetallic blades. The fatigue evaluation must
include consideration of all reasonably foreseeable
vibration load patterns. The fatigue limits must
account for the permissible service deteriortion
(such as nicks, grooves, galling, bearing wear, and
variations in material properties).
(a)
Fixed-pitch wood propellers. Fixed-pitch wood
propellers must be subjected to one of the following
tests:
(1)
A 10-hour endurance block test on an engine with a
propeller of the greatest pitch and diameter for
which certification is sought at the rated
rotational speed.
(2)
A 50-hour flight test in level flight or in climb.
At least five hours of this flight test must be with
the propeller operated at the rated rotational
speed, and the remainder of the 50 hours must be
with the propeller operated at not less than 90
percent of the rated rotational speed. This test
must be conducted on a propeller of the greatest
diameter for which certification is requested.
(3)
A 50-hour endurance block test on an engine at the
power and propeller rotational speed for which
certification is sought. This test must be conducted
on a propeller of the greatest diameter for which
certification is requested.
(b)
Fixed-pitch metal propellers and ground
adjustable-pitch propellers. Each fixed-pitch
metal propeller or ground adjustable-pitch propeller
must be subjected to the test prescribed in either
paragraph (a)(2) or (a)(3) of this section.
(c)
Variable-pitch propellers. Compliance with
this paragraph must be shown for a propeller of the
greatest diameter for which certification is
requested. Each variable-pitch propeller (a
propeller the pitch setting of which can be changed
by the flight crew or by automatic means while the
propeller is rotating) must be subjected to one of
the following tests:
(1)
A 100-hour test on a representative engine with the
same or higher power and rotational speed and the
same or more severe vibration characteristics as the
engine with which the propeller is to be used. Each
test must be made at the maximum continuous
rotational speed and power rating of the propeller.
If a takeoff rating greater than the maximum
continuous rating is to be established, and
additional 10-hour block test must be made at the
maximum power and rotational speed for the takeoff
rating.
(2)
Operation of the propeller throughout the engine
endurance tests prescribed in Part 33 of this
subchapter.
(a)
Each variable-pitch propeller must be subjected to
the applicable functional tests of this section. The
same propeller used in the endurance test must be
used in the functional tests and must be driven by
an engine on a test stand or on an aircraft.
(b)
Manually controllable propellers. 500
complete cycles of control must be made throughout
the pitch and rotational speed ranges.
(c)
Automatically controllable propellers. 1,500
complete cycles of control must be made throughout
the pitch and rotational speed ranges.
(d)
Feathering propellers. 50 cycles of
feathering operation must be made.
(e)
Reversible-pitch propellers. Two hundred
complete cycles of control must be made from lowest
normal pitch to maximum reverse pitch, and, while in
maximum reverse pitch, during each cycle, the
propeller must be run for 30 seconds at the maximum
power and rotational speed selected by the applicant
for maximum reverse pitch.
The
following durability requirements apply to propeller
blade pitch control system components:
(a)
Except as provided in paragraph (b) of this section,
each propeller blade pitch control system component,
including governors, pitch change assemblies, pitch
locks, mechanical stops, and feathering system
components, must be subjected in tests to cyclic
loadings that simulate the frequency and amplitude
those to which the component would be subjected
during 1,000 hours of propeller operation.
(b)
Compliance with paragraph (a) of this section may be
shown by a rational analysis based on the results of
tests on similar components.
The
Administrator may require any additional tests he
finds necessary to substantiate the use of any
unconventional features of design, material, or
construction.
(a)
After completion of the tests prescribed in this
subpart, the propeller must be completely
disassembled and a detailed inspection must be made
of the propeller parts for cracks, wear, distortion,
and any other unusual conditions.
(b)
After the inspection the applicant must make any
changes to the design or any additional tests that
the Administrator finds necessary to establish the
airworthiness of the propeller.
The
applicant may service and make minor repairs to the
propeller during the tests. If major repairs or
replacement of parts are found necessary during the
tests or in the teardown inspection, the parts in
question must be subjected to any additional tests
the Administrator finds necessary.
a35.1 general
(a)
This appendix specifies requirements for the
preparation of Instructions for Continued
Airworthiness as required by 35.4.
(b)
The Instructions for Continued Airworthiness for
each propeller must include the Instructions for
Continued Airworthiness for all propeller parts. If
Instructions for Continued Airworthiness are not
supplied by the propeller part manufacturer for a
propeller part, the Instructions for Continued
Airworthiness for the propeller must include the
information essential to the continued airworthiness
of the propeller.
(c)
The applicant must submit to the AFRO-CAA a program
to show how changes to the Instructions for
Continued Airworthiness made by the applicant or by
the manufacturers of propeller parts will be
distributed.
a35.2 format
(a)
The Instructions for Continued Airworthiness must be
in the form of a manual or manuals as appropriate
for the quantity of data to be provided.
(b)
The format of the manual or manuals must provide for
a practical arrangement.
a35.3 content
The
contents of the manual must be prepared in the
English language. The Instructions for Continued
Airworthiness must contain the following sections
and information:
(a)
Propeller Maintenance Section. (1)
Introduction information that includes an
explanation of the propeller's features and data to
the extent necessary for maintenance or preventive
maintenance.
(2)
A detailed description of the propeller and its
systems and installations.
(3)
Basic control and operation information describing
how the propeller components and systems are
controlled and how they operate, including any
special procedures that apply.
(4)
Instructions for uncrating, acceptance checking,
lifting, and installing the propeller.
(5)
Instructions for propeller operational checks.
(6)
Scheduling information for each part of the
propeller that provides the recommended periods at
which it should be cleaned, adjusted, and tested,
the applicable wear tolerances, and the degree of
work recommended at these periods. However, the
applicant may refer to an accessory, instrument, or
equipment manufacturer as the source of this
information if it shows that the item has an
exceptionally high degree of complexity requiring
specialized maintenance techniques, test equipment,
or expertise. The recommended overhaul periods and
necessary cross-references to the Airworthiness
Limitations section of the manual must also be
included. In addition, the applicant must include an
inspection program that includes the frequency and
extent of the inspections necessary to provide for
the continued airworthiness of the propeller.
(7)
Troubleshooting information describing probable
malfunctions, how to recognize those malfunctions,
and the remedial action for those malfunctions.
(8)
Information describing the order and method of
removing and replacing propeller parts with any
necessary precautions to be taken.
(9)
A list of the special tools needed for maintenance
other than for overhauls.
(b)
Propeller Overhaul Section. (1) Disassembly
information including the order and method of
disassembly for overhaul.
(2)
Cleaning and inspection instructions that cover the
materials and apparatus to be used and methods and
precautions to be taken during overhaul. Methods of
overhaul inspection must also be included.
(3)
Details of all fits and clearances relevant to
overhaul.
(4)
Details of repair methods for worn or otherwise
substandard parts and components along with
information necessary to determine when replacement
is necessary.
(5)
The order and method of assembly at overhaul.
(6)
Instructions for testing after overhaul.
(7)
Instructions for storage preparation including any
storage limits.
(8)
A list of tools needed for overhaul.
a35.4 airworthiness limitations section
The
Instructions for Continued Airworthiness must
contain a section titled Airworthiness Limitations
that is segregated and clearly distinguishable from
the rest of the document. This section must set
forth each mandatory replacement time, inspection
interval, and related procedure required for type
certification. This section must contain a legible
statement in a prominent location that reads: “The
Airworthiness Limitations section is AFRO-CAA
approved and specifies maintenance required under
43.16 and 91.403 of the African Civil Aviation
Regulations unless an alternative program has been
AFRO-CAA approved.”
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