PART 33--AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES
Subpart A--General
Sec.
33.1 Applicability.
33.3 General.
33.4 Instructions for Continued Airworthiness.
33.5 Instruction manual for installing and operating the engine.
33.7 Engine ratings and operating limitations.
33.8 Selection of engine power and thrust ratings.
Subpart B--Design and Construction; General
33.11 Applicability.
33.13 [Reserved]
33.14 Start-stop cyclic stress (low-cycle fatigue).
33.15 Materials.
33.17 Fire prevention.
33.19 Durability.
33.21 Engine cooling.
33.23 Engine mounting attachments and structure.
33.25 Accessory attachments.
33.27 Turbine, compressor, fan, and turbosupercharger rotors.
33.28 Electrical and electronic engine control systems.
33.29 Instrument connection.
Subpart C--Design and Construction; Reciprocating Aircraft Engines
Note: For miscellaneous amendments to cross references in this Part 33, see
Amdt. 33-2, 31 FR 9211, July 6, 1966.
Subpart A--General
Sec. 33.1 Applicability.
(a) This part prescribes airworthiness standards for the issue of type
certificates and changes to those certificates, for aircraft engines.
(b) Each person who applies under part 21 for such a certificate or change
must show compliance with the applicable requirements of this part and the
applicable requirements of part 34 of this chapter.
[Amdt. 33-7, 41 FR 55474, Dec. 20, 1976, as amended by Amdt. 33-14, 55 FR
32861, Aug. 10, 1990]
Sec. 33.3 General.
Each applicant must show that the aircraft engine concerned meets the
applicable requirements of this part.
Sec. 33.4 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 engine installed, or upon issuance of a standard
certificate of airworthiness for the aircraft with the engine installed,
whichever occurs later.
[Amdt. 33-9, 45 FR 60181, Sept. 11, 1980]
Sec. 33.5 Instruction manual for installing and operating the engine.
Each applicant must prepare and make available to the Administrator prior
to the issuance of the type certificate, and to the owner at the time of
delivery of the engine, approved instructions for installing and operating
the engine. The instructions must include at least the following:
(a) Installation instructions. (1) The location of engine mounting
attachments, the method of attaching the engine to the aircraft, and the
maximum allowable load for the mounting attachments and related structure.
(2) The location and description of engine connections to be attached to
accessories, pipes, wires, cables, ducts, and cowling.
(3) An outline drawing of the engine including overall dimensions.
(b) Operation instructions. (1) The operating limitations established by
the Administrator.
(2) The power or thrust ratings and procedures for correcting for
nonstandard atmosphere.
(3) The recommended procedures, under normal and extreme ambient conditions
for--
(i) Starting;
(ii) Operating on the ground; and
(iii) Operating during flight.
[Amdt. 33-6, 39 FR 35463, Oct. 1, 1974, as amended by Amdt. 33-9, 45 FR
60181, Sept. 11, 1980]
Sec. 33.7 Engine ratings and operating limitations.
(a) Engine ratings and operating limitations are established by the
Administrator and included in the engine certificate data sheet specified in
Sec. 21.41 of this chapter, including ratings and limitations based on the
operating conditions and information specified in this section, as
applicable, and any other information found necessary for safe operation of
the engine.
(b) For reciprocating engines, ratings and operating limitations are
established relating to the following:
(1) Horsepower or torque, r.p.m., manifold pressure, and time at critical
pressure altitude and sea level pressure altitude for--
(i) Rated maximum continuous power (relating to unsupercharged operation or
to operation in each supercharger mode as applicable); and
(ii) Rated takeoff power (relating to unsupercharged operation or to
operation in each supercharger mode as applicable).
(2) Fuel grade or specification.
(3) Oil grade or specification.
(4) Temperature of the--
(i) Cylinder;
(ii) Oil at the oil inlet; and
(iii) Turbosupercharger turbine wheel inlet gas.
(5) Pressure of--
(i) Fuel at the fuel inlet; and
(ii) Oil at the main oil gallery.
(6) Accessory drive torque and overhang moment.
(7) Component life.
(8) Turbosupercharger turbine wheel r.p.m.
(c) For turbine engines, ratings and operating limitations are established
relating to the following:
(1) Horsepower, torque, or thrust, r.p.m., gas temperature, and time for--
(i) Rated maximum continuous power or thrust (augmented);
(ii) Rated maximum continuous power or thrust (unaugmented);
(iii) Rated takeoff power or thrust (augmented);
(iv) Rated takeoff power or thrust (unaugmented);
(v) Rated 30-minute OEI power;
(vi) Rated 2 1/2 -minute OEI power;
(vii) Rated continuous OEI power; and
(viii) Auxiliary power unit (APU) mode of operation.
(2) Fuel designation or specification.
(3) Oil grade or specification.
(4) Hydraulic fluid specification.
(5) Temperature of--
(i) Oil at a location specified by the applicant;
(ii) Induction air at the inlet face of a supersonic engine, including
steady state operation and transient over-temperature and time allowed;
(iii) Hydraulic fluid of a supersonic engine;
(iv) Fuel at a location specified by the applicant; and
(v) External surfaces of the engine, if specified by the applicant.
(6) Pressure of--
(i) Fuel at the fuel inlet;
(ii) Oil at a location specified by the applicant;
(iii) Induction air at the inlet face of a supersonic engine, including
steady state operation and transient overpressure and time allowed; and
(iv) Hydraulic fluid.
(7) Accessory drive torque and overhang moment.
(8) Component life.
(9) Fuel filtration.
(10) Oil filtration.
(11) Bleed air.
(12) The number of start-stop stress cycles approved for each rotor disc
and spacer.
(13) Inlet air distortion at the engine inlet.
(14) Transient rotor shaft overspeed r.p.m., and number of overspeed
occurrences.
(15) Transient gas overtemperature, and number of overtemperature
occurrences.
(16) For engines to be used in supersonic aircraft, engine rotor
windmilling rotational r.p.m.
Sec. 33.8 Selection of engine power and thrust ratings.
(a) Requested engine power and thrust ratings must be selected by the
applicant.
(b) Each selected rating must be for the lowest power or thrust that all
engines of the same type may be expected to produce under the conditions used
to determine that rating.
[Amdt. 33-3, 32 FR 3736, Mar. 4, 1967]
Subpart B--Design and Construction; General
Sec. 33.11 Applicability.
This subpart prescribes the general design and construction requirements
for reciprocating and turbine aircraft engines.
Sec. 33.13 [Reserved]
Sec. 33.14 Start-stop cyclic stress (low-cycle fatigue).
By a procedure approved by the FAA, operating limitations must be
established which specify the maximum allowable number of start-stop stress
cycles for each rotor structural part (such as discs, spacers, hubs, and
shafts of the compressors and turbines), the failure of which could produce a
hazard to the aircraft. A start-stop stress cycle consists of a flight cycle
profile or an equivalent representation of engine usage. It includes starting
the engine, accelerating to maximum rated power or thrust, decelerating, and
stopping. For each cycle, the rotor structural parts must reach stabilized
temperature during engine operation at a maximum rate power or thrust and
after engine shutdown, unless it is shown that the parts undergo the same
stress range without temperature stabilization.
[Amdt. 33-10, 49 FR 6850, Feb. 23, 1984]
Sec. 33.15 Materials.
The suitability and durability of materials used in the engine must--
(a) Be established on the basis of experience or tests; and
(b) Conform to approved specifications (such as industry or military
specifications) that ensure their having the strength and other properties
assumed in the design data.
(Secs. 313(a), 601, and 603, 72 Stat. 759, 775, 49 U.S.C. 1354(a), 1421, and
1423; sec. 6(c), 49 U.S.C. 1655(c))
[Amdt. 33-8, 42 FR 15047, Mar. 17, 1977, as amended by Amdt. 33-10, 49 FR
6850, Feb. 23, 1984]
Sec. 33.17 Fire prevention.
(a) The design and construction of the engine and the materials used must
minimize the probability of the occurrence and spread of fire. In addition,
the design and construction of turbine engines must minimize the probability
of the occurrence of an internal fire that could result in structural
failure, overheating, or other hazardous conditions.
(b) Except as provided in paragraphs (c), (d), and (e) of this section,
each external line, fitting, and other component, which contains or conveys
flammable fluid must be fire resistant. Components must be shielded or
located to safeguard against the ignition of leaking flammable fluid.
(c) Flammable fluid tanks and supports which are part of and attached to
the engine must be fireproof or be enclosed by a fireproof shield unless
damage by fire to any non-fireproof part will not cause leakage or spillage
of flammable fluid. For a reciprocating engine having an integral oil sump of
less than 25-quart capacity, the oil sump need not be fireproof nor be
enclosed by fireproof shield.
(d) For turbine engines type certificated for use in supersonic aircraft,
each external component which conveys or contains flammable fluid must be
fireproof.
(e) Unwanted accumulation of flammable fluid and vapor must be prevented by
draining and venting.
(Secs. 313(a), 601, and 603, 72 Stat. 759, 775, 49 U.S.C. 1354(a), 1421, and
1423; sec. 6(c), 49 U.S.C. 1655(c))
[Amdt. 33-6, 39 FR 35464, Oct. 1, 1974, as amended by Amdt. 33-8, 42 FR
15047, Mar. 17, 1977; Amdt. 33-10, 49 FR 6850, Feb. 23, 1984]
Sec. 33.19 Durability.
(a) Engine design and construction must minimize the development of an
unsafe condition of the engine between overhaul periods. The design of the
compressor and turbine rotor cases must provide for the containment of damage
from rotor blade failure. Energy levels and trajectories of fragments
resulting from rotor blade failure that lie outside the compressor and
turbine rotor cases must be defined.
(b) Each component of the propeller blade pitch control system which is a
part of the engine type design must meet the requirements of Sec. 35.42 of
this chapter.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-9, 45 FR
60181, Sept. 11, 1980; Amdt. 33-10, 49 FR 6851, Feb. 23, 1984]
Sec. 33.21 Engine cooling.
Engine design and construction must provide the necessary cooling under
conditions in which the airplane is expected to operate.
Sec. 33.23 Engine mounting attachments and structure.
(a) The maximum allowable limit and ultimate loads for engine mounting
attachments and related engine structure must be specified.
(b) The engine mounting attachments and related engine structure must be
able to withstand--
(1) The specified limit loads without permanent deformation; and
(2) The specified ultimate loads without failure, but may exhibit permanent
deformation.
[Amdt. 33-10, 49 FR 6851, Feb. 23, 1984]
Sec. 33.25 Accessory attachments.
The engine must operate properly with the accessory drive and mounting
attachments loaded. Each engine accessory drive and mounting attachment must
include provisions for sealing to prevent contamination of, or unacceptable
leakage from, the engine interior. A drive and mounting attachment requiring
lubrication for external drive splines, or coupling by engine oil, must
include provisions for sealing to prevent unacceptable loss of oil and to
prevent contamination from sources outside the chamber enclosing the drive
connection. The design of the engine must allow for the examination,
adjustment, or removal of each accessory required for engine operation.
[Amdt. 33-10, 49 FR 6851, Feb. 23, 1984]
Sec. 33.27 Turbine, compressor, fan, and turbosupercharger rotors.
(a) Turbine, compressor, fan, and turbosupercharger rotors must have
sufficient strength to withstand the test conditions specified in paragraph
(c) of this section.
(b) The design and functioning of engine control devices, systems, and
instruments must give reasonable assurance that those engine operating
limitations that affect turbine, compressor, fan, and turbosupercharger rotor
structural integrity will not be exceeded in service.
(c) The most critically stressed rotor component (except blades) of each
turbine, compressor, and fan, including integral drum rotors and centrifugal
compressors in an engine or turbosupercharger, as determined by analysis or
other acceptable means, must be tested for a period of 5 minutes--
(1) At its maximum operating temperature, except as provided in paragraph
(c)(2)(iv) of this section; and
(2) At the highest speed of the following, as applicable:
(i) 120 percent of its maximum permissible r.p.m. if tested on a rig and
equipped with blades or blade weights.
(ii) 115 percent of its maximum permissible r.p.m. if tested on an engine.
(iii) 115 percent of its maximum permissible r.p.m. if tested on
turbosupercharger driven by a hot gas supply from a special burner rig.
(iv) 120 percent of the r.p.m. at which, while cold spinning, it is subject
to operating stresses that are equivalent to those induced at the maximum
operating temperature and maximum permissible r.p.m.
(v) 105 percent of the highest speed that would result from failure of the
most critical component or system in a representative installation of the
engine.
(vi) The highest speed that would result from the failure of any component
or system in a representative installation of the engine, in combination with
any failure of a component or system that would not normally be detected
during a routine preflight check or during normal flight operation.
Following the test, each rotor must be within approved dimensional limits for
an overspeed condition and may not be cracked.
[Amdt. 33-10, 49 FR 6851, Feb. 23, 1984]
Sec. 33.28 Electrical and electronic engine control systems.
Each control system which relies on electrical and electronic means for
normal operation must:
(a) Have the control system description, the percent of available power or
trust controlled in both normal operation and failure conditions, and the
range of control of other controlled functions, specified in the instruction
manual required by Sec. 33.5 for the engine;
(b) Be designed and constructed so that any failure of aircraft-supplied
power or data will not result in an unacceptable change in power or thrust,
or prevent continued safe operation of the engine;
(c) Be designed and constructed so that no single failure or malfunction,
or probable combination of failures of electrical or electronic components of
the control system, results in an unsafe condition;
(d) Have environmental limits, including transients caused by lightning
strikes, specified in the instruction manual; and
(e) Have all associated software designed and implemented to prevent errors
that would result in an unacceptable loss of power or thrust, or other unsafe
condition, and have the method used to design and implement the software
approved by the Administrator.
[Amdt. 33-15, 58 FR 29095, May 18, 1993]
Sec. 33.29 Instrument connection.
(a) Unless it is constructed to prevent its connection to an incorrect
instrument, each connection provided for powerplant instruments required by
aircraft airworthiness regulations or necessary to insure operation of the
engine in compliance with any engine limitation must be marked to identify it
with its corresponding instrument.
(b) A connection must be provided on each turbojet engine for an indicator
system to indicate rotor system unbalance.
[Amdt. 33-5, 39 FR 1831, Jan. 15, 1974, as amended by Amdt. 33-6, 39 FR
35465, Oct. 1, 1974]
Subpart C--Design and Construction; Reciprocating Aircraft Engines
Sec. 33.31 Applicability.
This subpart prescribes additional design and construction requirements for
reciprocating aircraft engines.
Sec. 33.33 Vibration.
The engine must be designed and constructed to function throughout its
normal operating range of crankshaft rotational speeds and engine powers
without inducing excessive stress in any of the engine parts because of
vibration and without imparting excessive vibration forces to the aircraft
structure.
Sec. 33.35 Fuel and induction system.
(a) The fuel system of the engine must be designed and constructed to
supply an appropriate mixture of fuel to the cylinders throughout the
complete operating range of the engine under all flight and atmospheric
conditions.
(b) The intake passages of the engine through which air or fuel in
combination with air passes for combustion purposes must be designed and
constructed to minimize the danger of ice accretion in those passages. The
engine must be designed and constructed to permit the use of a means for ice
prevention.
(c) The type and degree of fuel filtering necessary for protection of the
engine fuel system against foreign particles in the fuel must be specified.
The applicant must show that foreign particles passing through the prescribed
filtering means will not critically impair engine fuel system functioning.
(d) Each passage in the induction system that conducts a mixture of fuel
and air must be self-draining, to prevent a liquid lock in the cylinders, in
all attitudes that the applicant establishes as those the engine can have
when the aircraft in which it is installed is in the static ground attitude.
(e) If provided as part of the engine, the applicant must show for each
fluid injection (other than fuel) system and its controls that the flow of
the injected fluid is adequately controlled.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-10, 49 FR
6851, Feb. 23, 1984]
Sec. 33.37 Ignition system.
Each spark ignition engine must have a dual ignition system with at least
two spark plugs for each cylinder and two separate electric circuits with
separate sources of electrical energy, or have an ignition system of
equivalent in-flight reliability.
Sec. 33.39 Lubrication system.
(a) The lubrication system of the engine must be designed and constructed
so that it will function properly in all flight attitudes and atmospheric
conditions in which the airplane is expected to operate. In wet sump engines,
this requirement must be met when only one-half of the maximum lubricant
supply is in the engine.
(b) The lubrication system of the engine must be designed and constructed
to allow installing a means of cooling the lubricant.
(c) The crankcase must be vented to the atmosphere to preclude leakage of
oil from excessive pressure in the crankcase.
This subpart prescribes the block tests and inspections for reciprocating
aircraft engines.
Sec. 33.42 General.
Before each endurance test required by this subpart, the adjustment setting
and functioning characteristic of each component having an adjustment setting
and a functioning characteristic that can be established independent of
installation on the engine must be established and recorded.
[Amdt. 33-6, 39 FR 35465, Oct. 1, 1974]
Sec. 33.43 Vibration test.
(a) Each engine must undergo a vibration survey to establish the torsional
and bending vibration characteristics of the crankshaft and the propeller
shaft or other output shaft, over the range of crankshaft speed and engine
power, under steady state and transient conditions, from idling speed to
either 110 percent of the desired maximum continuous speed rating or 103
percent of the maximum desired takeoff speed rating, whichever is higher. The
survey must be conducted using, for airplane engines, the same configuration
of the propeller type which is used for the endurance test, and using, for
other engines, the same configuration of the loading device type which is
used for the endurance test.
(b) The torsional and bending vibration stresses of the crankshaft and the
propeller shaft or other output shaft may not exceed the endurance limit
stress of the material from which the shaft is made. If the maximum stress in
the shaft cannot be shown to be below the endurance limit by measurement, the
vibration frequency and amplitude must be measured. The peak amplitude must
be shown to produce a stress below the endurance limit; if not, the engine
must be run at the condition producing the peak amplitude until, for steel
shafts, 10 million stress reversals have been sustained without fatigue
failure and, for other shafts, until it is shown that fatigue will not occur
within the endurance limit stress of the material.
(c) Each accessory drive and mounting attachment must be loaded, with the
loads imposed by each accessory used only for an aircraft service being the
limit load specified by the applicant for the drive or attachment point.
(d) The vibration survey described in paragraph (a) of this section must be
repeated with that cylinder not firing which has the most adverse vibration
effect, in order to establish the conditions under which the engine can be
operated safely in that abnormal state. However, for this vibration survey,
the engine speed range need only extend from idle to the maximum desired
takeoff speed, and compliance with paragraph (b) of this section need not be
shown.
[Amdt. 33-6, 39 FR 35465, Oct. 1, 1974, as amended by Amdt. 33-10, 49 FR
6851, Feb. 23, 1984]
Sec. 33.45 Calibration tests.
(a) Each engine must be subjected to the calibration tests necessary to
establish its power characteristics and the conditions for the endurance test
specified in Sec. 33.49. The results of the power characteristics calibration
tests form the basis for establishing the characteristics of the engine over
its entire operating range of crankshaft rotational speeds, manifold
pressures, fuel/air mixture settings, and altitudes. Power ratings are based
upon standard atmospheric conditions with only those accessories installed
which are essential for engine functioning.
(b) A power check at sea level conditions must be accomplished on the
endurance test engine after the endurance test. Any change in power
characteristics which occurs during the endurance test must be determined.
Measurements taken during the final portion of the endurance test may be used
in showing compliance with the requirements of this paragraph.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-6, 39 FR
35465, Oct. 1, 1974]
Sec. 33.47 Detonation test.
Each engine must be tested to establish that the engine can function
without detonation throughout its range of intended conditions of operation.
Sec. 33.49 Endurance test.
(a) General. Each engine must be subjected to an endurance test that
includes a total of 150 hours of operation (except as provided in paragraph
(e)(1)(iii) of this section) and, depending upon the type and contemplated
use of the engine, consists of one of the series of runs specified in
paragraphs (b) through (e) of this section, as applicable. The runs must be
made in the order found appropriate by the Administrator for the particular
engine being tested. During the endurance test the engine power and the
crankshaft rotational speed must be kept within +/-3 percent of the rated
values. During the runs at rated takeoff power and for at least 35 hours at
rated maximum continuous power, one cylinder must be operated at not less
than the limiting temperature, the other cylinders must be operated at a
temperature not lower than 50 degrees F. below the limiting temperature, and
the oil inlet temperature must be maintained within +/-10 degrees F. of the
limiting temperature. An engine that is equipped with a propeller shaft must
be fitted for the endurance test with a propeller that thrust-loads the
engine to the maximum thrust which the engine is designed to resist at each
applicable operating condition specified in this section. Each accessory
drive and mounting attachment must be loaded. During operation at rated
takeoff power and rated maximum continuous power, the load imposed by each
accessory used only for an aircraft service must be the limit load specified
by the applicant for the engine drive or attachment point.
(b) Unsupercharged engines and engines incorporating a gear-driven single-
speed supercharger. For engines not incorporating a supercharger and for
engines incorporating a gear-driven single-speed supercharger the applicant
must conduct the following runs:
(1) A 30-hour run consisting of alternate periods of 5 minutes at rated
takeoff power with takeoff speed, and 5 minutes at maximum best economy
cruising power or maximum recommended cruising power.
(2) A 20-hour run consisting of alternate periods of 1 1/2 hours at rated
maximum continuous power with maximum continuous speed, and 1/2 hour at 75
percent rated maximum continuous power and 91 percent maximum continuous
speed.
(3) A 20-hour run consisting of alternate periods of 1 1/2 hours at rated
maximum continuous power with maximum continuous speed, and 1/2 hour at 70
percent rated maximum continuous power and 89 percent maximum continuous
speed.
(4) A 20-hour run consisting of alternate periods of 1 1/2 hours at rated
maximum continuous power with maximum continuous speed, and 1/2 hour at 65
percent rated maximum continuous power and 87 percent maximum continuous
speed.
(5) A 20-hour run consisting of alternate periods of 1 1/2 hours at rated
maximum continuous power with maximum continuous speed, and 1/2 hour at 60
percent rated maximum continuous power and 84.5 percent maximum continuous
speed.
(6) A 20-hour run consisting of alternate periods of 1 1/2 hours at rated
maximum continuous power with maximum continuous speed, and 1/2 hour at 50
percent rated maximum continuous power and 79.5 percent maximum continuous
speed.
(7) A 20-hour run consisting of alternate periods of 2 1/2 hours at rated
maximum continuous power with maximum continuous speed, and 2 1/2 hours at
maximum best economy cruising power or at maximum recommended cruising power.
(c) Engines incorporating a gear-driven two-speed supercharger. For engines
incorporating a gear-driven two-speed supercharger the applicant must conduct
the following runs:
(1) A 30-hour run consisting of alternate periods in the lower gear ratio
of 5 minutes at rated takeoff power with takeoff speed, and 5 minutes at
maximum best economy cruising power or at maximum recommended cruising power.
If a takeoff power rating is desired in the higher gear ratio, 15 hours of
the 30-hour run must be made in the higher gear ratio in alternate periods of
5 minutes at the observed horsepower obtainable with the takeoff critical
altitude manifold pressure and takeoff speed, and 5 minutes at 70 percent
high ratio rated maximum continuous power and 89 percent high ratio maximum
continuous speed.
(2) A 15-hour run consisting of alternate periods in the lower gear ratio
of 1 hour at rated maximum continuous power with maximum continuous speed,
and 1/2 hour at 75 percent rated maximum continuous power and 91 percent
maximum continuous speed.
(3) A 15-hour run consisting of alternate periods in the lower gear ratio
of 1 hour at rated maximum continuous power with maximum continuous speed,
and 1/2 hour at 70 percent rated maximum continuous power and 89 percent
maximum continuous speed.
(4) A 30-hour run in the higher gear ratio at rated maximum continuous
power with maximum continuous speed.
(5) A 5-hour run consisting of alternate periods of 5 minutes in each of
the supercharger gear ratios. The first 5 minutes of the test must be made at
maximum continuous speed in the higher gear ratio and the observed horsepower
obtainable with 90 percent of maximum continuous manifold pressure in the
higher gear ratio under sea level conditions. The condition for operation for
the alternate 5 minutes in the lower gear ratio must be that obtained by
shifting to the lower gear ratio at constant speed.
(6) A 10-hour run consisting of alternate periods in the lower gear ratio
of 1 hour at rated maximum continuous power with maximum continuous speed,
and 1 hour at 65 percent rated maximum continuous power and 87 percent
maximum continuous speed.
(7) A 10-hour run consisting of alternate periods in the lower gear ratio
of 1 hour at rated maximum continuous power with maximum continuous speed,
and 1 hour at 60 percent rated maximum continuous power and 84.5 percent
maximum continuous speed.
(8) A 10-hour run consisting of alternate periods in the lower gear ratio
of 1 hour at rated maximum continuous power with maximum continuous speed,
and 1 hour at 50 percent rated maximum continuous power and 79.5 percent
maximum continuous speed.
(9) A 20-hour run consisting of alternate periods in the lower gear ratio
of 2 hours at rated maximum continuous power with maximum continuous speed,
and 2 hours at maximum best economy cruising power and speed or at maximum
recommended cruising power.
(10) A 5-hour run in the lower gear ratio at maximum best economy cruising
power and speed or at maximum recommended cruising power and speed.
Where simulated altitude test equipment is not available when operating in
the higher gear ratio, the runs may be made at the observed horsepower
obtained with the critical altitude manifold pressure or specified
percentages thereof, and the fuel-air mixtures may be adjusted to be rich
enough to suppress detonation.
(d) Helicopter engines. To be eligible for use on a helicopter each engine
must either comply with paragraphs (a) through (j) of Sec. 29.923 of this
chapter, or must undergo the following series of runs:
(1) A 35-hour run consisting of alternate periods of 30 minutes each at
rated takeoff power with takeoff speed, and at rated maximum continuous power
with maximum continuous speed.
(2) A 25-hour run consisting of alternate periods of 2 1/2 hours each at
rated maximum continuous power with maximum continuous speed, and at 70
percent rated maximum continuous power with maximum continuous speed.
(3) A 25-hour run consisting of alternate periods of 2 1/2 hours each at
rated maximum continuous power with maximum continuous speed, and at 70
percent rated maximum continuous power with 80 to 90 percent maximum
continuous speed.
(4) A 25-hour run consisting of alternate periods of 2 1/2 hours each at
30 percent rated maximum continuous power with takeoff speed, and at 30
percent rated maximum continuous power with 80 to 90 percent maximum
continuous speed.
(5) A 25-hour run consisting of alternate periods of 2 1/2 hours each at
80 percent rated maximum continuous power with takeoff speed, and at either
rated maximum continuous power with 110 percent maximum continuous speed or
at rated takeoff power with 103 percent takeoff speed, whichever results in
the greater speed.
(6) A 15-hour run at 105 percent rated maximum continuous power with 105
percent maximum continuous speed or at full throttle and corresponding speed
at standard sea level carburetor entrance pressure, if 105 percent of the
rated maximum continuous power is not exceeded.
(e) Turbosupercharged engines. For engines incorporating a
turbosupercharger the following apply except that altitude testing may be
simulated provided the applicant shows that the engine and supercharger are
being subjected to mechanical loads and operating temperatures no less severe
than if run at actual altitude conditions:
(1) For engines used in airplanes the applicant must conduct the runs
specified in paragraph (b) of this section, except--
(i) The entire run specified in paragraph (b)(1) of this section must be
made at sea level altitude pressure;
(ii) The portions of the runs specified in paragraphs (b) (2) through (7)
of this section at rated maximum continuous power must be made at critical
altitude pressure, and the portions of the runs at other power must be made
at 8,000 feet altitude pressure; and
(iii) The turbosupercharger used during the 150-hour endurance test must be
run on the bench for an additional 50 hours at the limiting turbine wheel
inlet gas temperature and rotational speed for rated maximum continuous power
operation unless the limiting temperature and speed are maintained during 50
hours of the rated maximum continuous power operation.
(2) For engines used in helicopters the applicant must conduct the runs
specified in paragraph (d) of this section, except--
(i) The entire run specified in paragraph (d)(1) of this section must be
made at critical altitude pressure;
(ii) The portions of the runs specified in paragraphs (d) (2) and (3) of
this section at rated maximum continuous power must be made at critical
altitude pressure and the portions of the runs at other power must be made at
8,000 feet altitude pressure;
(iii) The entire run specified in paragraph (d)(4) of this section must be
made at 8,000 feet altitude pressure;
(iv) The portion of the runs specified in paragraph (d)(5) of this section
at 80 percent of rated maximum continuous power must be made at 8,000 feet
altitude pressure and the portions of the runs at other power must be made at
critical altitude pressure;
(v) The entire run specified in paragraph (d)(6) of this section must be
made at critical altitude pressure; and
(vi) The turbosupercharger used during the endurance test must be run on
the bench for 50 hours at the limiting turbine wheel inlet gas temperature
and rotational speed for rated maximum continuous power operation unless the
limiting temperature and speed are maintained during 50 hours of the rated
maximum continuous power operation.
[Amdt. 33-3, 32 FR 3736, Mar. 4, 1967, as amended by Amdt. 33-6, 39 FR 35465,
Oct. 1, 1974; Amdt. 33-10, 49 FR 6851, Feb. 23, 1984]
Sec. 33.51 Operation test.
The operation test must include the testing found necessary by the
Administrator to demonstrate backfire characteristics, starting, idling,
acceleration, overspeeding, functioning of propeller and ignition, and any
other operational characteristic of the engine. If the engine incorporates a
multispeed supercharger drive, the design and construction must allow the
supercharger to be shifted from operation at the lower speed ratio to the
higher and the power appropriate to the manifold pressure and speed settings
for rated maximum continuous power at the higher supercharger speed ratio
must be obtainable within five seconds.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-3, 32 FR
3737, Mar. 4, 1967]
Sec. 33.53 Engine component tests.
(a) For each engine that cannot be adequately substantiated by endurance
testing in accordance with Sec. 33.49, the applicant must conduct additional
tests to establish that components are able to function reliably in all
normally anticipated flight and atmospheric conditions.
(b) Temperature limits must be established for each component that requires
temperature controlling provisions in the aircraft installation to assure
satisfactory functioning, reliability, and durability.
Sec. 33.55 Teardown inspection.
After completing the endurance test--
(a) Each engine must be completely disassembled;
(b) Each component having an adjustment setting and a functioning
characteristic that can be established independent of installation on the
engine must retain each setting and functioning characteristic within the
limits that were established and recorded at the beginning of the test; and
(c) Each engine component must conform to the type design and be eligible
for incorporation into an engine for continued operation, in accordance with
information submitted in compliance with Sec. 33.4.
[Amdt. 33-6, 39 FR 35466, Oct. 1, 1974, as amended by Amdt. 33-9, 45 FR
60181, Sept. 11, 1980]
Sec. 33.57 General conduct of block tests.
(a) The applicant may, in conducting the block tests, use separate engines
of identical design and construction in the vibration, calibration,
detonation, endurance, and operation tests, except that, if a separate engine
is used for the endurance test it must be subjected to a calibration check
before starting the endurance test.
(b) The applicant may service and make minor repairs to the engine during
the block tests in accordance with the service and maintenance instructions
submitted in compliance with Sec. 33.4. If the frequency of the service is
excessive, or the number of stops due to engine malfunction is excessive, or
a major repair, or replacement of a part is found necessary during the block
tests or as the result of findings from the teardown inspection, the engine
or its parts may be subjected to any additional test the Administrator finds
necessary.
(c) Each applicant must furnish all testing facilities, including equipment
and competent personnel, to conduct the block tests.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-6, 39 FR
35466, Oct. 1, 1974; Amdt. 33-9, 45 FR 60181, Sept. 11, 1980]
Subpart E--Design and Construction; Turbine Aircraft Engines
Sec. 33.61 Applicability.
This subpart prescribes additional design and construction requirements for
turbine aircraft engines.
Sec. 33.62 Stress analysis.
A stress analysis must be performed on each turbine engine showing the
design safety margin of each turbine engine rotor, spacer, and rotor shaft.
[Amdt. 33-6, 39 FR 35466, Oct. 1, 1974]
Sec. 33.63 Vibration.
Each engine must be designed and constructed to function throughout its
operating range of rotational speeds and engine power without inducing
excessive stress in any engine part because of vibration and without
imparting excessive vibration forces to the aircraft structure.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-10, 49 FR
6851, Feb. 23, 1984]
Sec. 33.65 Surge and stall characteristics.
When the engine is operated in accordance with operating instructions
required by Sec. 33.5(b), starting, a change of power or thrust, power or
thrust augmentation, limiting inlet air distortion, or inlet air temperature
may not cause surge or stall to the extent that flameout, structural failure,
overtemperature, or failure of the engine to recover power or thrust will
occur at any point in the operating envelope.
[Amdt. 33-6, 39 FR 35466, Oct. 1, 1974]
Sec. 33.66 Bleed air system.
The engine must supply bleed air without adverse effect on the engine,
excluding reduced thrust or power output, at all conditions up to the
discharge flow conditions established as a limitation under Sec. 33.7(c)(11).
If bleed air used for engine anti-icing can be controlled, provision must be
made for a means to indicate the functioning of the engine ice protection
system.
[Amdt. 33-10, 49 FR 6851, Feb. 23, 1984]
Sec. 33.67 Fuel system.
(a) With fuel supplied to the engine at the flow and pressure specified by
the applicant, the engine must function properly under each operating
condition required by this part. Each fuel control adjusting means that may
not be manipulated while the fuel control device is mounted on the engine
must be secured by a locking device and sealed, or otherwise be inaccessible.
All other fuel control adjusting means must be accessible and marked to
indicate the function of the adjustment unless the function is obvious.
(b) There must be a fuel strainer or filter between the engine fuel inlet
opening and the inlet of either the fuel metering device or the engine-driven
positive displacement pump whichever is nearer the engine fuel inlet. In
addition, the following provisions apply to each strainer or filter required
by this paragraph (b):
(1) It must be accessible for draining and cleaning and must incorporate a
screen or element that is easily removable.
(2) It must have a sediment trap and drain except that it need not have a
drain if the strainer or filter is easily removable for drain purposes.
(3) It must be mounted so that its weight is not supported by the
connecting lines or by the inlet or outlet connections of the strainer or
filter, unless adequate strength margins under all loading conditions are
provided in the lines and connections.
(4) It must have the type and degree of fuel filtering specified as
necessary for protection of the engine fuel system against foreign particles
in the fuel. The applicant must show:
(i) That foreign particles passing through the specified filtering means do
not impair the engine fuel system functioning; and
(ii) That the fuel system is capable of sustained operation throughout its
flow and pressure range with the fuel initially saturated with water at 80
deg. F (27 deg. C) and having 0.025 fluid ounces per gallon (0.20 milliliters
per liter) of free water added and cooled to the most critical condition for
icing likely to be encountered in operation. However, this requirement may be
met by demonstrating the effectiveness of specified approved fuel anti-icing
additives, or that the fuel system incorporates a fuel heater which maintains
the fuel temperature at the fuel strainer or fuel inlet above 32 deg. F (0
deg. C) under the most critical conditions.
(5) The applicant must demonstrate that the filtering means has the
capacity (with respect to engine operating limitations) to ensure that the
engine will continue to operate within approved limits, with fuel
contaminated to the maximum degree of particle size and density likely to be
encountered in service. Operation under these conditions must be demonstrated
for a period acceptable to the Administrator, beginning when indication of
impending filter blockage is first given by either:
(i) Existing engine instrumentation; or
(ii) Additional means incorporated into the engine fuel system.
(6) Any strainer or filter bypass must be designed and constructed so that
the release of collected contaminants is minimized by appropriate location of
the bypass to ensure that collected contaminants are not in the bypass flow
path.
(c) If provided as part of the engine, the applicant must show for each
fluid injection (other than fuel) system and its controls that the flow of
the injected fluid is adequately controlled.
[Amdt. 33-6, 39 FR 35466, Oct. 1, 1974, as amended by Amdt. 33-10, 49 FR
6851, Feb. 23, 1984]
Sec. 33.68 Induction system icing.
Each engine, with all icing protection systems operating, must--
(a) Operate throughout its flight power range (including idling) without
the accumulation of ice on the engine components that adversely affects
engine operation or that causes a serious loss of power or thrust in
continuous maximum and intermittent maximum icing conditions as defined in
Appendix C of Part 25 of this chapter; and
(b) Idle for 30 minutes on the ground, with the available air bleed for
icing protection at its critical condition, without adverse effect, in an
atmosphere that is at a temperature between 15 deg. and 30 deg. F (between -9
deg. and -1 deg. C) and has a liquid water content not less than 0.3 grams
per cubic meter in the form of drops having a mean effective diameter not
less than 20 microns, followed by a momentary operation at takeoff power or
thrust. During the 30 minutes of idle operation the engine may be run up
periodically to a moderate power or thrust setting in a manner acceptable to
the Administrator.
[Amdt. 33-6, 39 FR 35466, Oct. 1, 1974, as amended by Amdt. 33-10, 49 FR
6852, Feb. 23, 1984]
Sec. 33.69 Ignitions system.
Each engine must be equipped with an ignition system for starting the
engine on the ground and in flight. An electric ignition system must have at
least two igniters and two separate secondary electric circuits, except that
only one igniter is required for fuel burning augmentation systems.
[Amdt. 33-6, 39 FR 35466, Oct. 1, 1974]
Sec. 33.71 Lubrication system.
(a) General. Each lubrication system must function properly in the flight
attitudes and atmospheric conditions in which an aircraft is expected to
operate.
(b) Oil strainer or filter. There must be an oil strainer or filter through
which all of the engine oil flows. In addition:
(1) Each strainer or filter required by this paragraph that has a bypass
must be constructed and installed so that oil will flow at the normal rate
through the rest of the system with the strainer or filter element completely
blocked.
(2) The type and degree of filtering necessary for protection of the engine
oil system against foreign particles in the oil must be specified. The
applicant must demonstrate that foreign particles passing through the
specified filtering means do not impair engine oil system functioning.
(3) Each strainer or filter required by this paragraph must have the
capacity (with respect to operating limitations established for the engine)
to ensure that engine oil system functioning is not impaired with the oil
contaminated to a degree (with respect to particle size and density) that is
greater than that established for the engine in paragraph (b)(2) of this
section.
(4) For each strainer or filter required by this paragraph, except the
strainer or filter at the oil tank outlet, there must be means to indicate
contamination before it reaches the capacity established in accordance with
paragraph (b)(3) of this section.
(5) Any filter bypass must be designed and constructed so that the release
of collected contaminants is minimized by appropriate location of the bypass
to ensure that the collected contaminants are not in the bypass flow path.
(6) Each strainer or filter required by this paragraph that has no bypass,
except the strainer or filter at an oil tank outlet or for a scavenge pump,
must have provisions for connection with a warning means to warn the pilot of
the occurence of contamination of the screen before it reaches the capacity
established in accordance with paragraph (b)(3) of this section.
(7) Each strainer or filter required by this paragraph must be accessible
for draining and cleaning.
(c) Oil tanks. (1) Each oil tank must have an expansion space of not less
than 10 percent of the tank capacity.
(2) It must be impossible to inadvertently fill the oil tank expansion
space.
(3) Each recessed oil tank filler connection that can retain any
appreciable quantity of oil must have provision for fitting a drain.
(4) Each oil tank cap must provide an oil-tight seal.
(5) Each oil tank filler must be marked with the word "oil."
(6) Each oil tank must be vented from the top part of the expansion space,
with the vent so arranged that condensed water vapor that might freeze and
obstruct the line cannot accumulate at any point.
(7) There must be means to prevent entrance into the oil tank or into any
oil tank outlet, of any object that might obstruct the flow of oil through
the system.
(8) There must be a shutoff valve at the outlet of each oil tank, unless
the external portion of the oil system (including oil tank supports) is
fireproof.
(9) Each unpressurized oil tank may not leak when subjected to a maximum
operating temperature and an internal pressure of 5 p.s.i., and each
pressurized oil tank may not leak when subjected to maximum operating
temperature and an internal pressure that is not less than 5 p.s.i. plus the
maximum operating pressure of the tank.
(10) Leaked or spilled oil may not accumulate between the tank and the
remainder of the engine.
(11) Each oil tank must have an oil quantity indicator or provisions for
one.
(12) If the propeller feathering system depends on engine oil--
(i) There must be means to trap an amount of oil in the tank if the supply
becomes depleted due to failure of any part of the lubricating system other
than the tank itself;
(ii) The amount of trapped oil must be enough to accomplish the feathering
opeation and must be available only to the feathering pump; and
(iii) Provision must be made to prevent sludge or other foreign matter from
affecting the safe operation of the propeller feathering system.
(d) Oil drains. A drain (or drains) must be provided to allow safe drainage
of the oil system. Each drain must--
(1) Be accessible; and
(2) Have manual or automatic means for positive locking in the closed
position.
(e) Oil radiators. Each oil radiator must withstand, without failure, any
vibration, inertia, and oil pressure load to which it is subjected during the
block tests.
[Amdt. 33-6, 39 FR 35466, Oct. 1, 1974, as amended by Amdt. 33-10, 49 FR
6852, Feb. 23, 1984]
Sec. 33.72 Hydraulic actuating systems.
Each hydraulic actuating system must function properly under all conditions
in which the engine is expected to operate. Each filter or screen must be
accessible for servicing and each tank must meet the design criteria of Sec.
33.71.
[Amdt. 33-6, 39 FR 35467, Oct. 1, 1974]
Sec. 33.73 Power or thrust response.
The design and construction of the engine must enable an increase--
(a) From minimum to rated takeoff power or thrust with the maximum bleed
air and power extraction to be permitted in an aircraft, without
overtemperature, surge, stall, or other detrimental factors occurring to the
engine whenever the power control lever is moved from the minimum to the
maximum position in not more than 1 second, except that the Administrator may
allow additional time increments for different regimes of control operation
requiring control scheduling; and
(b) From the fixed minimum flight idle power lever position when provided,
or if not provided, from not more than 15 percent of the rated takeoff power
or thrust available to 95 percent rated takeoff power or thrust in not over 5
seconds. The 5-second power or thrust response must occur from a stabilized
static condition using only the bleed air and accessories loads necessary to
run the engine. This takeoff rating is specified by the applicant and need
not include thrust augmentation.
[Amdt. 33-1, 36 FR 5493, Mar. 24, 1971]
Sec. 33.75 Safety analysis.
It must be shown by analysis that any probable malfunction or any probable
single or multiple failure, or any probable improper operation of the engine
will not cause the engine to--
(a) Catch fire;
(b) Burst (release hazardous fragments through the engine case);
(c) Generate loads greater than those ultimate loads specified in Sec.
33.23(a); or
(d) Lose the capability of being shut down.
[Amdt. 33-6, 39 FR 35467, Oct. 1, 1974, as amended by Amdt. 33-10, 49 FR
6852, Feb. 23, 1984]
Sec. 33.77 Foreign object ingestion.
(a) Ingestion of a 4-pound bird, under the conditions prescribed in
paragraph (e) of this section, may not cause the engine to--
(1) Catch fire;
(2) Burst (release hazardous fragments through the engine case);
(3) Generate loads greater than those ultimate loads specified in Sec.
33.23(a); or
(4) Lose the capability of being shut down.
(b) Ingestion of 3-ounce birds or 1 1/2 -pound birds, under the conditions
prescribed in paragraph (e) of this section, may not--
(1) Cause more than a sustained 25 percent power or thrust loss;
(2) Require the engine to be shut down within 5 minutes from the time of
ingestion; or
(3) Result in a potentially hazardous condition.
(c) Ingestion of water, ice, or hail, under the conditions prescribed in
paragraph (e) of this section, may not cause a sustained power or thrust loss
or require the engine to be shut down. It must be demonstrated that the
engine can accelerate and decelerate safely while inducting a mixture of at
least 4 percent water by weight of engine airflow following stabilized
operation at both flight idle and takeoff power settings with at least a 4
percent water-to-air ratio.
(d) For an engine that incorporates a protection device, compliance with
this section need not be demonstrated with respect to foreign objects to be
ingested under the conditions prescribed in paragraph (e) of this section if
it is shown that--
(1) Such foreign objects are of a size that will not pass through the
protective device;
(2) The protective device will withstand the impact of the foreign objects;
and
(3) The foreign object, or objects, stopped by the protective device will
not obstruct the flow of induction air into the engine with a resultant
sustained reduction in power or thrust greater than those values required by
paragraphs (b) and (c) of this section.
(e) Compliance with paragraphs (a), (b), and (c) of this section must be
shown by engine test under the following ingestion conditions:
Foreign Speed of Engine
object Test quantity foreign object operation Ingestion
Birds:
3-ounce size One for each Liftoff speed Takeoff In rapid
50 square of typical sequence to
inches of aircraft simulate a
inlet area or flock
fraction encounter
thereof up to and aimed at
a maximum of selected
16 birds. critical
Three-ounce areas.
bird
ingestion not
required if a
1 1/2 -pound
bird will
pass the
inlet guide
vanes into
the rotor
blades
1 1/2 -pound One for the Initial climb Takeoff In rapid
size first 300 speed of sequence to
square inches typical simulate a
of inlet aircraft flock
area, if it encounter
can enter the and aimed at
inlet, plus selected
one for each critical
additional areas.
600 square
inches of
inlet area or
fraction
thereof up to
a maximum of
8 birds
4-pound size One, if it can Maximum climb Maximum cruise Aimed at
enter the speed of critical
inlet typical area.
aircraft if
the engine has
inlet guide
vanes
Liftoff speed Takeoff Aimed at
of typical critical
aircraft, if area.
the engine
does not have
inlet guide
vanes
Ice Maximum Sucked in Maximum cruise To simulate a
accumulation continuous
on a typical maximum
inlet cowl icing
and engine encounter at
face 25 deg.F.
resulting
from a 2-
minute delay
in actuating
anti-icing
system, or a
slab of ice
which is
comparable in
weight or
thickness for
that size
engine
Hail (0.8 to For all Rough air Maximum cruise In a volley
0.9 specific engines: With flight speed at 15,000 to simulate
gravity) inlet area of of typical feet altitude a hailstone
not more than aircraft encounter.
100 square One-half the
inches: one number of
1-inch hailstones
hailstone. aimed at
With inlet random area
area of more over the
than 100 face of the
square inlet and
inches: one the other
1-inch and half aimed
one 2-inch at the
hailstone for critical
each 150 face area.
square inches
of inlet area
or fraction
thereof
For supersonic Supersonic Maximum cruise Aimed at
engines (in cruise critical
addition): 3 velocity. engine face
hailstones Alternatively, area.
each having a use subsonic
diameter velocities
equal to that with larger
in a straight hailstones to
line give
variation equivalent
from 1 inch kinetic energy
at 35,000
feet to 1/4
inch at
60,000 feet
using
diameter
corresponding
to the lowest
supersonic
cruise
altitude
expected
Water At least 4 Sucked in Flight idle, For 3 minutes
percent of acceleration, each at idle
engine takeoff, and takeoff,
airflow by deceleration and during
weight acceleration
and
deceleration
in spray to
simulate
rain.
Note.--The term "inlet area" as used in this section means the engine inlet
projected area at the front face of the engine. It includes the projected
area of any spinner or bullet nose that is provided.
[Amdt. 33-10, 49 FR 6852, Feb. 23, 1984]
Sec. 33.79 Fuel burning thrust augmentor.
Each fuel burning thrust augmentor, including the nozzle, must--
(a) Provide cutoff of the fuel burning thrust augmentor;
(b) Permit on-off cycling;
(c) Be controllable within the intended range of operation;
(d) Upon a failure or malfunction of augmentor combustion, not cause the
engine to lose thrust other than that provided by the augmentor; and
(e) Have controls that function compatibly with the other engine controls
and automatically shut off augmentor fuel flow if the engine rotor speed
drops below the minimum rotational speed at which the augmentor is intended
to function.
[Amdt. 33-6, 39 FR 35468, Oct. 1, 1974]
Subpart F--Block Tests; Turbine Aircraft Engines
Sec. 33.81 Applicability.
This subpart prescribes the block tests and inspections for turbine
engines.
[Doc. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-6, 39 FR 35468,
Oct. 1, 1974]
Sec. 33.82 General.
Before each endurance test required by this subpart, the adjustment setting
and functioning characteristic of each component having an adjustment setting
and a functioning characteristic that can be established independent of
installation on the engine must be established and recorded.
[Amdt. 36-6, 39 FR 35468, Oct. 1, 1974]
Sec. 33.83 Vibration test.
(a) Each engine must undergo a vibration survey to establish the vibration
characteristics of the rotor discs, rotor blades, rotor shafts, stator
blades, and any other components that are subject to vibratory exciting
forces which could induce failure at the maximum inlet distortion limit. The
survey is to cover the range of rotor speeds and engine power or thrust,
under steady state and transient conditions, from idling speed to 103 percent
of the maximum permissible speed. The survey must be conducted using the same
configuration of the loading device which is used for the endurance test,
except that the Administrator may allow the use of a modified configuration
if that loading device type is incompatible with the necessary vibration
instrumentation.
(b) The vibration stresses (or strains) of rotor and stator components
determined under paragraph (a) of this section must be less, by a margin
acceptable to the Administrator, than the endurance limit of the material
from which these parts are made, adjusted for the most severe operating
conditions.
(c) Each accessory drive and mounting attachment must be loaded, with the
load imposed by each accessory used only for an aircraft service being the
limit load specified by the applicant for the engine drive or attachment
point.
[Amdt. 33-6, 39 FR 35468, Oct. 1, 1974, as amended by Amdt. 33-10, 49 FR
6853, Feb. 23, 1984]
Sec. 33.85 Calibration tests.
(a) Each engine must be subjected to those calibration tests necessary to
establish its power characteristics and the conditions for the endurance test
specified Sec. 33.87. The results of the power characteristics calibration
tests form the basis for establishing the characteristics of the engine over
its entire operating range of speeds, pressures, temperatures, and altitudes.
Power ratings are based upon standard atmospheric conditions with no airbleed
for aircraft services and with only those accessories installed which are
essential for engine functioning.
(b) A power check at sea level conditions must be accomplished on the
endurance test engine after the endurance test and any change in power
characteristics which occurs during the endurance test must be determined.
Measurements taken during the final portion of the endurance test may be used
in showing compliance with the requirements of this paragraph.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-6, 39 FR
35468, Oct. 1, 1974]
Sec. 33.87 Endurance test.
(a) General. Each engine must be subjected to an endurance test that
includes a total of 150 hours of operation and, depending upon the type and
contemplated use of the engine, consists of one of the series of runs
specified in paragraphs (b) through (f) of this section, as applicable. For
engines tested under paragraph (b), (c), (d), or (e) of this section, the
prescribed 6-hour test sequence must be conducted 25 times to complete the
required 150 hours of operation. The following test requirements apply:
(1) The runs must be made in the order found appropriate by the
Administrator for the particular engine being tested.
(2) Any automatic engine control that is part of the engine must control
the engine during the endurance test except for operations where automatic
control is normally overridden by manual control or where manual control is
otherwise specified for a particular test run.
(3) Except as provided in paragraph (a)(5) of this section, power or
thrust, gas temperature, rotor shaft rotational speed, and, if limited,
temperature of external surfaces of the engine must be at least 100 percent
of the value associated with the particular engine operation being tested.
More than one test may be run if all parameters cannot be held at the 100
percent level simultaneously.
(4) The runs must be made using fuel, lubricants and hydraulic fluid which
conform to the specifications specified in complying with Sec. 33.7(c).
(5) Maximum air bleed for engine and aircraft services must be used during
at least one-fifth of the runs. However, for these runs, the power or thrust
or the rotor shaft rotational speed may be less than 100 percent of the value
associated with the particular operation being tested if the Administrator
finds that the validity of the endurance test is not compromised.
(6) Each accessory drive and mounting attachment must be loaded. The load
imposed by each accessory used only for aircraft service must be the limit
load specified by the applicant for the engine drive and attachment point
during rated maximum continuous power or thrust and higher output. The
endurance test of any accessory drive and mounting attachment under load may
be accomplished on a separate rig if the validity of the test is confirmed by
an approved analysis.
(7) During the runs at any rated power or thrust the gas temperature and
the oil inlet temperature must be maintained at the limiting temperature
except where the test periods are not longer than 5 minutes and do not allow
stabilization. At least one run must be made with fuel, oil, and hydraulic
fluid at the minimum pressure limit and at least one run must be made with
fuel, oil, and hydraulic fluid at the maximum pressure limit with fluid
temperature reduced as necessary to allow maximum pressure to be attained.
(8) If the number of occurrences of either transient rotor shaft overspeed
or transient gas overtemperature is limited, that number of the accelerations
required by paragraphs (b), (c), (d), and (e) of this section must be made at
the limiting overspeed or overtemperature. If the number of occurrences is
not limited, half the required accelerations must be made at the limiting
overspeed or overtemperature.
(9) For each engine type certificated for use on supersonic aircraft the
following additional test requirements apply:
(i) To change the thrust setting, the power control lever must be moved
from the initial position to the final position in not more than one second
except for movements into the fuel burning thrust augmentor augmentation
position if additional time to confirm ignition is necessary.
(ii) During the runs at any rated augmented thrust the hydraulic fluid
temperature must be maintained at the limiting temperature except where the
test periods are not long enough to allow stabilization.
(iii) During the simulated supersonic runs the fuel temperature and
induction air temperature may not be less than the limiting temperature.
(iv) The endurance test must be conducted with the fuel burning thrust
augmentor installed, with the primary and secondary exhaust nozzles
installed, and with the variable area exhaust nozzles operated during each
run according to the methods specified in complying with Sec. 33.5(b).
(v) During the runs at thrust settings for maximum continuous thrust and
percentages thereof, the engine must be operated with the inlet air
distortion at the limit for those thrust settings.
(b) Engines other than certain rotorcraft engines. For each engine except a
rotorcraft engine for which a rating is desired under paragraph (c), (d), or
(e) of this section, the applicant must conduct the following runs:
(1) Takeoff and idling. One hour of alternate five-minute periods at rated
takeoff power and thrust and at idling power and thrust. The developed powers
and thrusts at takeoff and idling conditions and their corresponding rotor
speed and gas temperature conditions must be as established by the power
control in accordance with the schedule established by the manufacturer. The
applicant may, during any one period, manually control the rotor speed,
power, and thrust while taking data to check performance. For engines with
augmented takeoff power ratings that involve increases in turbine inlet
temperature, rotor speed, or shaft power, this period of running at takeoff
must be at the augmented rating. For engines with augmented takeoff power
ratings that do not materially increase operating severity, the amount of
running conducted at the augmented rating is determined by the Administrator.
In changing the power setting after each period, the power-control lever must
be moved in the manner prescribed in paragraph (b)(5) of this section.
(2) Rated maximum continuous and takeoff power and thrust. Thirty minutes
at--
(i) Rated maximum continuous power and thrust during fifteen of the twenty-
five 6-hour endurance test cycles; and
(ii) Rated takeoff power and thrust during ten of the twenty-five 6-hour
endurance test cycles.
(3) Rated maximum continuous power and thrust. One hour and 30 minutes at
rated maximum continuous power and thrust.
(4) Incremental cruise power and thrust. Two hours and 30 minutes at the
successive power lever positions corresponding to at least 15 approximately
equal speed and time increments between maximum continuous engine rotational
speed and ground or minimum idle rotational speed. For engines operating at
constant speed, the thrust and power may be varied in place of speed. If
there is significant peak vibration anywhere between ground idle and maximum
continuous conditions, the number of increments chosen may be changed to
increase the amount of running made while subject to the peak vibrations up
to not more than 50 percent of the total time spent in incremental running.
(5) Acceleration and deceleration runs. 30 minutes of accelerations and
decelerations, consisting of six cycles from idling power and thrust to rated
takeoff power and thrust and maintained at the takeoff power lever position
for 30 seconds and at the idling power lever position for approximately four
and one-half minutes. In complying with this paragraph, the power-control
lever must be moved from one extreme poition to the other in not more than
one second, except that, if different regimes of control operations are
incorporated necessitating scheduling of the power-control lever motion in
going from one extreme position to the other, a longer period of time is
acceptable, but not more than two seconds.
(6) Starts. One hundred starts must be made, of which 25 starts must be
preceded by at least a two-hour engine shutdown. There must be at least 10
false engine starts, pausing for the applicant's specified minimum fuel
drainage time, before attempting a normal start. There must be at least 10
normal restarts with not longer than 15 minutes since engine shutdown. The
remaining starts may be made after completing the 150 hours of endurance
testing.
(c) Rotorcraft engines for which a 30-minute OEI power rating is desired.
For each rotorcraft engine for which a 30-minute OEI power rating is desired,
the applicant must conduct the following series of tests:
(1) Takeoff and idling. One hour of alternate 5-minute periods at rated
takeoff power and at idling power. The developed powers at takeoff and idling
conditions and their corresponding rotor speed and gas temperature conditions
must be as established by the power control in accordance with the schedule
established by the manufacturer. During any one period, the rotor speed and
power may be controlled manually while taking data to check performance. For
engines with augmented takeoff power ratings that involve increases in
turbine inlet temperature, rotor speed, or shaft power, this period of
running at rated takeoff power must be at the augmented power rating. In
changing the power setting after each period, the power control lever must be
moved in the manner prescribed in paragraph (c)(5) of this section.
(2) Rated 30-minute OEI power. Thirty minutes at rated 30-minute OEI power.
(3) Rated maximum continuous power. Two hours at rated maximum continuous
power.
(4) Incremental cruise power. Two hours at the successive power lever
positions corresponding with not less than 12 approximately equal speed and
time increments between maximum continuous engine rotational speed and ground
or minimum idle rotational speed. For engines operating at constant speed,
power may be varied in place of speed. If there are significant peak
vibrations anywhere between ground idle and maximum continuous conditions,
the number of increments chosen must be changed to increase the amount of
running conducted while being subjected to the peak vibrations up to not more
than 50 percent of the total time spent in incremental running.
(5) Acceleration and deceleration runs. Thirty minutes of accelerations and
decelerations, consisting of six cycles from idling power to rated takeoff
power and maintained at the takeoff power lever position for 30 seconds and
at the idling power lever position for approximately 4 1/2 minutes. In
complying with this paragraph, the power control lever must be moved from one
extreme position to the other in not more than 1 second, except that if
different regimes of control operations are incorporated necessitating
scheduling of the power control lever motion in going from one extreme
position to the other, a longer period of time is acceptable, but not more
than 2 seconds.
(6) Starts. One hundred starts, of which 25 starts must be preceded by at
least a two-hour engine shutdown. There must be at least 10 false engine
starts, pausing for the applicant's specified minimum fuel drainage time,
before attempting a normal start. There must be at least 10 normal restarts
with not longer than 15 minutes since engine shutdown. The remaining starts
may be made after completing the 150 hours of endurance testing.
(d) Rotorcraft engines for which a continuous OEI rating is desired. For
each rotorcraft engine for which a continuous OEI power rating is desired,
the applicant must conduct the following series of tests:
(1) Takeoff and idling. One hour of alternate 5-minute periods at rated
takeoff power and at idling power. The developed powers at takeoff and idling
conditions and their corresponding rotor speed and gas temperature conditions
must be as established by the power control in accordance with the schedule
established by the manufacturer. During any one period the rotor speed and
power may be controlled manually while taking data to check performance. For
engines with augmented takeoff power ratings that involve increases in
turbine inlet temperature, rotor speed, or shaft power, this period of
running at rated takeoff power must be at the augmented power rating. In
changing the power setting after each period, the power control lever must be
moved in the manner prescribed in paragraph (c)(5) of this section.
(2) Rated maximum continuous and takeoff power. Thirty minutes at--
(i) Rated maximum continuous power during fifteen of the twenty-five 6-hour
endurance test cycles; and
(ii) Rated takeoff power during ten of the twenty-five 6-hour endurance
test cycles.
(3) Rated continuous OEI power. One hour at rated continuous OEI power.
(4) Rated maximum continuous power. One hour at rated maximum continuous
power.
(5) Incremental cruise power. Two hours at the successive power lever
positions corresponding with not less than 12 approximately equal speed and
time increments between maximum continuous engine rotational speed and ground
or minimum idle rotational speed. For engines operating at constant speed,
power may be varied in place of speed. If there are significant peak
vibrations anywhere between ground idle and maximum continuous conditions,
the number of increments chosen must be changed to increase the amount of
running conducted while being subjected to the peak vibrations up to not more
than 50 percent of the total time spent in incremental running.
(6) Acceleration and deceleration runs. Thirty minutes of accelerations and
decelerations, consisting of six cycles from idling power to rated takeoff
power and maintained at the takeoff power lever position for 30 seconds and
at the idling power lever position for approximately 4 1/2 minutes. In
complying with this paragraph, the power control lever must be moved from one
extreme position to the other in not more than 1 second, except that if
different regimes of control operations are incorporated necessitating
scheduling of the power control lever motion in going from one extreme
position to the other, a longer period of time is acceptable, but not more
than 2 seconds.
(7) Starts. One hundred starts, of which 25 starts must be preceded by at
least a 2-hour engine shutdown. There must be at least 10 false engine
starts, pausing for the applicant's specified minimum fuel drainage time,
before attempting a normal start. There must be at least 10 normal restarts
with not longer than 15 minutes since engine shutdown. The remaining starts
may be made after completing the 150 hours of endurance testing.
(e) Rotorcraft engines for which a 2 1/2 -minute OEI power rating is
desired. For each rotorcraft engine for which a 2 1/2 -minute OEI power
rating is desired, the applicant must conduct the following series of tests:
(1) Takeoff, 2 1/2 -minute OEI, and idling. One hour of alternate 5-minute
periods at rated takeoff power and at idling power except that, during the
third and sixth takeoff power periods, only 2 1/2 minutes need be conducted
at rated takeoff power, and the remaining 2 1/2 minutes must be conducted at
rated 2 1/2 -minute OEI power. The developed powers at takeoff, 2 1/2 -minute
OEI, and idling conditions and their corresponding rotor speed and gas
temperature conditions must be as established by the power control in
accordance with the schedule established by the manufacturer. The applicant
may, during any one period, control manually the rotor speed and power while
taking data to check performance. For engines with augmented takeoff power
ratings that involve increases in turbine inlet temperature, rotor speed, or
shaft power, this period of running at rated takeoff power must be at the
augmented rating. In changing the power setting after or during each period,
the power control lever must be moved in the manner prescribed in paragraph
(d)(6) of this section.
(2) The tests required in paragraphs (b)(2) through (b)(6), or (c)(2)
through (c)(6), or (d)(2) through (d)(7) of this section, as applicable,
except that in one of the 6-hour test sequences, the last 5 minutes of the 30
minutes at takeoff power test period of paragraph (b)(2) of this section, or
of the 30 minutes at 30-minute OEI power test period of paragraph (c)(2) of
this section, or of the l hour at continuous OEI power test period of
paragraph (d)(3) of this section, must be run at 2 1/2 -minute OEI power.
(f) Supersonic aircraft engines. For each engine type certificated for use
on supersonic aircraft the applicant must conduct the following:
(1) Subsonic test under sea level ambient atmospheric conditions. Thirty
runs of one hour each must be made, consisting of--
(i) Two periods of 5 minutes at rated takeoff augmented thrust each
followed by 5 minutes at idle thrust;
(ii) One period of 5 minutes at rated takeoff thrust followed by 5 minutes
at not more than 15 percent of rated takeoff thrust;
(iii) One period of 10 minutes at rated takeoff augmented thrust followed
by 2 minutes at idle thrust, except that if rated maximum continuous
augmented thrust is lower than rated takeoff augmented thrust, 5 of the 10-
minute periods must be at rated maximum continuous augmented thrust; and
(iv) Six periods of 1 minute at rated takeoff augmented thrust each
followed by 2 minutes, including acceleration and deceleration time, at idle
thrust.
(2) Simulated supersonic test. Each run of the simulated supersonic test
must be preceded by changing the inlet air temperature and pressure from that
attained at subsonic condition to the temperature and pressure attained at
supersonic velocity, and must be followed by a return to the temperature
attained at subsonic condition. Thirty runs of 4 hours each must be made,
consisting of--
(i) One period of 30 minutes at the thrust obtained with the power control
lever set at the position for rated maximum continuous augmented thrust
followed by 10 minutes at the thrust obtained with the power control lever
set at the position for 90 percent of rated maximum continuous augmented
thrust. The end of this period in the first five runs must be made with the
induction air temperature at the limiting condition of transient
overtemperature, but need not be repeated during the periods specified in
paragraphs (e)(2) (ii) through (iv) of this section;
(ii) One period repeating the run specified in paragraph (e)(2)(i) of this
section, except that it must be followed by 10 minutes at the thrust obtained
with the power control lever set at the position for 80 percent of rated
maximum continuous augmented thrust;
(iii) One period repeating the run specified in paragraph (e)(2)(i) of this
section, except that it must be followed by 10 minutes at the thrust obtained
with the power control lever set at the position for 60 percent of rated
maximum continuous augmented thrust and then 10 minutes at not more than 15
percent of rated takeoff thrust;
(iv) One period repeating the runs specified in paragraphs (e)(2) (i) and
(ii) of this section; and
(v) One period of 30 minutes with 25 of the runs made at the thrust
obtained with the power control lever set at the position for rated maximum
continuous augmented thrust, each followed by idle thrust and with the
remaining 5 runs at the thrust obtained with the power control lever set at
the position for rated maximum continuous augmented thrust for 25 minutes
each, followed by subsonic operation at not more than 15 percent or rated
takeoff thrust and accelerated to rated takeoff thrust for 5 minutes using
hot fuel.
(3) Starts. One hundred starts must be made, of which 25 starts must be
preceded by an engine shutdown of at least 2 hours. There must be at least 10
false engine starts, pausing for the applicant's specified minimum fuel
drainage time before attempting a normal start. At least 10 starts must be
normal restarts, each made no later than 15 minutes after engine shutdown.
The starts may be made at any time, including the period of endurance
testing.
Each engine must be run for 5 minutes at maximum permissible r.p.m with the
gas temperature at least 75 deg.F (42 deg.C) higher than the maximum
operating limit. Following this run, the turbine assembly must be within
serviceable limits.
[Amdt. 33-10, 49 FR 6853, Feb. 23, 1984]
Sec. 33.89 Operation test.
(a) The operation test must include testing found necessary by the
Administrator to demonstrate--
(1) Starting, idling, acceleration, overspeeding, ignition, functioning of
the propeller (if the engine is designated to operate with a propeller);
(2) Compliance with the engine response requirements of Sec. 33.73; and
(3) The minimum power or thrust response time to 95 percent rated takeoff
power or thrust, from power lever positions representative of minimum idle
and of minimum flight idle, starting from stabilized idle operation, under
the following engine load conditions:
(i) No bleed air and power extraction for aircraft use.
(ii) Maximum allowable bleed air and power extraction for aircraft use.
(iii) An intermediate value for bleed air and power extraction
representative of that which might be used as a maximum for aircraft during
approach to a landing.
(4) If testing facilities are not available, the determination of power
extraction required in paragraph (a)(3) (ii) and (iii) of this section may be
accomplished through appropriate analytical means.
(b) The operation test must include all testing found necessary by the
Administrator to demonstrate that the engine has safe operating
characteristics throughout its specified operating envelope.
[Amdt. 33-4, 36 FR 5493, Mar. 24, 1971, as amended by Amdt. 33-6, 39 FR
35469, Oct. 1, 1974; Amdt. 33-10, 49 FR 6853, Feb. 23, 1984]
Sec. 33.90 Initial maintenance inspection.
Each engine, except engines being type certificated through amendment of an
existing type certificate or through supplemental type certification
procedures, must undergo an approved test run that simulates the conditions
in which the engine is expected to operate in service, including typical
start-stop cycles, to establish when the initial maintenance inspection is
required. The test run must be accomplished on an engine which substantially
conforms to the final type design.
[Amdt. 33-10, 49 FR 6854, Feb. 23, 1984]
Sec. 33.91 Engine component tests.
(a) For those systems that cannot be adequately substantiated by endurance
testing in accordance with the provisions of Sec. 33.87, additional tests
must be made to establish that components are able to function reliably in
all normally anticipated flight and atmospheric conditions.
(b) Temperature limits must be established for those components that
require temperature controlling provisions in the aircraft installation to
assure satisfactory functioning, reliability, and durability.
(c) Each unpressurized hydraulic fluid tank may not fail or leak when
subjected to maximum operating temperature and an internal pressure of 5
p.s.i., and each pressurized hydraulic fluid tank may not fail or leak when
subjected to maximum operating temperature and an internal pressure not less
than 5 p.s.i. plus the maximum operating pressure of the tank.
(d) For an engine type certificated for use in supersonic aircraft, the
systems, safety devices, and external components that may fail because of
operation at maximum and minimum operating temperatures must be identified
and tested at maximum and minimum operating temperatures and while
temperature and other operating conditions are cycled between maximum and
minimum operating values.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-6, 39 FR
35469, Oct. 1, 1974]
Sec. 33.92 Windmilling tests.
(a) For engines to be used in supersonic aircraft, unless means are
incorporated in the engine to stop rotation of the engine rotors when the
engine is shut down in flight, each engine rotor must either seize or be
capable of rotation for 3 hours at the limiting windmilling rotational r.p.m.
with no oil in the engine system, without the engine--
(1) Catching fire;
(2) Bursting (releasing hazardous uncontained fragments); or
(3) Generating loads greater than those ultimate loads specified in Sec.
33.23(a).
(b) A turbojet or turbofan engine incorporating means to stop rotation of
the engine rotors when the engine is shut down in flight must be subjected to
25 operations under the following conditions:
(1) Each engine must be shut down while operating at rated maximum
continuous thrust.
(2) For engines certificated for use on supersonic aircraft, the
temperature of the induction air and the external surfaces of the engine must
be held at the maximum limit during the tests required by this paragraph.
[Amdt. 33-6, 39 FR 35470, Oct. 1, 1974, as amended by Amdt. 33-10, 49 FR
6854, Feb. 23, 1984]
Sec. 33.93 Teardown inspection.
After completing the endurance test each engine must be completely
disassembled, and--
(a) Each component having an adjustment setting and a functioning
characteristic that can be established independent of installation on the
engine must retain each setting and functioning characteristic within the
limits that were established and recorded at the beginning of the test; and
(b) Each engine part must conform to the type design and be eligible for
incorporation into an engine for continued operation, in accordance with
information submitted in compliance with Sec. 33.4.
Sec. 33.94 Blade containment and rotor unbalance tests.
(a) Except as provided in paragraph (b) of this section, it must be
demonstrated by engine tests that the engine is capable of containing damage
without catching fire and without failure of its mounting attachments when
operated for at least 15 seconds, unless the resulting engine damage induces
a self shutdown, after each of the following events:
(1) Failure of the most critical compressor or fan blade while operating at
maximum permissible r.p.m. The blade failure must occur at the outermost
retention groove or, for integrally-bladed rotor discs, at least 80 percent
of the blade must fail.
(2) Failure of the most critical turbine blade while operating at maximum
permissible r.p.m. The blade failure must occur at the outermost retention
groove or, for integrally-bladed rotor discs, at least 80 percent of the
blade must fail. The most critical turbine blade must be determined by
considering turbine blade weight and the strength of the adjacent turbine
case at case temperatures and pressures associated with operation at maximum
permissible r.p.m.
(b) Analysis based on rig testing, component testing, or service experience
may be substitute for one of the engine tests prescribed in paragraphs (a)(1)
and (a)(2) of this section if--
(1) That test, of the two prescribed, produces the least rotor unbalance;
and
(2) The analysis is shown to be equivalent to the test.
(Secs. 313(a), 601, and 603, Federal Aviation Act of 1958 (49 U.S.C. 1354(a),
1421, and 1423); and 49 U.S.C. 106(g) Revised, Pub. L. 97-449, Jan. 12, 1983)
[Amdt. 33-10, 49 FR 6854, Feb. 23, 1984]
Sec. 33.95 Engine-propeller systems tests.
If the engine is designed to operate with a propeller, the following tests
must be made with a representative propeller installed by either including
the tests in the endurance run or otherwise performing them in a manner
acceptable to the Administrator:
(a) Feathering operation: 25 cycles.
(b) Negative torque and thrust system operation: 25 cycles from rated
maximum continuous power.
(c) Automatic decoupler operation: 25 cycles from rated maximum continuous
power (if repeated decoupling and recoupling in service is the intended
function of the device).
(d) Reverse thrust operation: 175 cycles from the flight-idle position to
full reverse and 25 cycles at rated maximum continuous power from full
forward to full reverse thrust. At the end of each cycle the propeller must
be operated in reverse pitch for a period of 30 seconds at the maximum
rotational speed and power specified by the applicant for reverse pitch
operation.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-3, 32 FR
3737, Mar. 4, 1967]
Sec. 33.96 Engine tests in auxiliary power unit (APU) mode.
If the engine is designed with a propeller brake which will allow the
propeller to be brought to a stop while the gas generator portion of the
engine remains in operation, and remain stopped during operation of the
engine as an auxiliary power unit ("APU mode"), in addition to the
requirements of Sec. 33.87, the applicant must conduct the following tests:
(a) Ground locking: A total of 45 hours with the propeller brake engaged in
a manner which clearly demonstrates its ability to function without adverse
effects on the complete engine while the engine is operating in the APU mode
under the maximum conditions of engine speed, torque, temperature, air bleed,
and power extraction as specified by the applicant.
(b) Dynamic braking: A total of 400 application-release cycles of brake
engagements must be made in a manner which clearly demonstrates its ability
to function without adverse effects on the complete engine under the maximum
conditions of engine acceleration/deceleration rate, speed, torque, and
temperature as specified by the applicant. The propeller must be stopped
prior to brake release.
(c) One hundred engine starts and stops with the propeller brake engaged.
(d) The tests required by paragraphs (a), (b), and (c) of this section must
be performed on the same engine, but this engine need not be the same engine
used for the tests required by Sec. 33.87.
(e) The tests required by paragraphs (a), (b), and (c) of this section must
be followed by engine disassembly to the extent necessary to show compliance
with the requirements of Sec. 33.93(a) and Sec. 33.93(b).
[Amdt. 33-11, 51 FR 10346, Mar. 25, 1986]
Sec. 33.97 Thrust reversers.
(a) If the engine incorporates a reverser, the endurance calibration,
operation, and vibration tests prescribed in this subpart must be run with
the reverser installed. In complying with this section, the power control
lever must be moved from one extreme position to the other in not more than
one second except, if regimes of control operations are incorporated
necessitating scheduling of the power-control lever motion in going from one
extreme position to the other, a longer period of time is acceptable but not
more than three seconds. In addition, the test prescribed in paragraph (b) of
this section must be made. This test may be scheduled as part of the
endurance run.
(b) 175 reversals must be made from flight-idle forward thrust to maximum
reverse thrust and 25 reversals must be made from rated takeoff thrust to
maximum reverse thrust. After each reversal the reverser must be operated at
full reverse thrust for a period of one minute, except that, in the case of a
reverser intended for use only as a braking means on the ground, the reverser
need only be operated at full reverse thrust for 30 seconds.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-3, 32 FR
3737, Mar. 4, 1967]
Sec. 33.99 General conduct of block tests.
(a) Each applicant may, in making a block test, use separate engines of
identical design and construction in the vibration, calibration, endurance,
and operation tests, except that, if a separate engine is used for the
endurance test it must be subjected to a calibration check before starting
the endurance test.
(b) Each applicant may service and make minor repairs to the engine during
the block tests in accordance with the service and maintenance instructions
submitted in compliance with Sec. 33.4. If the frequency of the service is
excessive, or the number of stops due to engine malfunction is excessive, or
a major repair, or replacement of a part is found necessary during the block
tests or as the result of findings from the teardown inspection, the engine
or its parts must be subjected to any additional tests the Administrator
finds necessary.
(c) Each applicant must furnish all testing facilities, including equipment
and competent personnel, to conduct the block tests.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33-6, 39 FR
35470, Oct. 1, 1974; Amdt. 33-9, 45 FR 60181, Sept. 11, 1980]
Appendix A--Instructions for Continued Airworthiness
A33.1 GENERAL
(a) This appendix specifies requirements for the preparation of
Instructions for Continued Airworthiness as required by Sec. 33.4.
(b) The Instructions for Continued Airworthiness for each engine must
include the Instructions for Continued Airworthiness for all engine parts. If
Instructions for Continued Airworthiness are not supplied by the engine part
manufacturer for an engine part, the Instructions for Continued Airworthiness
for the engine must include the information essential to the continued
airworthiness of the engine.
(c) The applicant must submit to the FAA a program to show how changes to
the Instructions for Continued Airworthiness made by the applicant or by the
manufacturers of engine parts will be distributed.
A33.2 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.
A33.3 CONTENT
The contents of the manual or manuals must be prepared in the English
language. The Instructions for Continued Airworthiness must contain the
following manuals or sections, as appropriate, and information:
(a) Engine Maintenance Manual or Section. (1) Introduction information that
includes an explanation of the engine's features and data to the extent
necessary for maintenance or preventive maintenance.
(2) A detailed description of the engine and its components, systems, and
installations.
(3) Installation instructions, including proper procedures for uncrating,
deinhibiting, acceptance checking, lifting, and attaching accessories, with
any necessary checks.
(4) Basic control and operating information describing how the engine
components, systems, and installations operate, and information describing
the methods of starting, running, testing, and stopping the engine and its
parts including any special procedures and limitations that apply.
(5) Servicing information that covers details regarding servicing points,
capacities of tanks, reservoirs, types of fluids to be used, pressures
applicable to the various systems, locations of lubrication points,
lubricants to be used, and equipment required for servicing.
(6) Scheduling information for each part of the engine that provides the
recommended periods at which it should be cleaned, inspected, adjusted,
tested, and lubricated, and the degree of inspection the applicable wear
tolerances, and work recommended at these periods. However, the applicant may
refer to an accessory, instrument, or equipment manufacturer as the source of
this information if the applicant 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 engine.
(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 the engine and
its parts and replacing parts, with any necessary precautions to be taken.
Instructions for proper ground handling, crating, and shipping must also be
included.
(9) A list of the tools and equipment necessary for maintenance and
directions as to their method of use.
(b) Engine Overhaul Manual or 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 the 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.
A33.4 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. If the Instructions for Continued Airworthiness consist
of multiple documents, the section required by this paragraph must be
included in the principal manual. This section must contain a legible
statement in a prominent location that reads: "The Airworthiness Limitations
section is FAA approved and specifies maintenance required under Secs. 43.16
and 91.403 of the Federal Aviation Regulations unless an alternative program
has been FAA approved."
[Amdt. 33-9, 45 FR 60181, Sept. 11, 1980, as amended by Amdt. 33-13, 54 FR
34330, Aug. 18, 1989]
Effective Date Note At 54 FR 34330, Aug. 18, 1989, Sec. A33.4 in Appendix
A, Part 33 was amended by changing the cross reference "Sec. 91.163" to "Sec.
91.403", effective August 18, 1990.
