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Federal Aviation Administration, DOT
§ 33.71
§ 33.70
Engine life-limited parts.
By a procedure approved by the FAA,
operating limitations must be estab-
lished which specify the maximum al-
lowable number of flight cycles for
each engine life-limited part. Engine
life-limited parts are rotor and major
static structural parts whose primary
failure is likely to result in a haz-
ardous engine effect. Typically, engine
life-limited parts include, but are not
limited to disks, spacers, hubs, shafts,
high-pressure casings, and non-redun-
dant mount components. For the pur-
poses of this section, a hazardous en-
gine effect is any of the conditions list-
ed in § 33.75 of this part. The applicant
will establish the integrity of each en-
gine life-limited part by:
(a) An engineering plan that contains
the steps required to ensure each en-
gine life-limited part is withdrawn
from service at an approved life before
hazardous engine effects can occur.
These steps include validated analysis,
test, or service experience which en-
sures that the combination of loads,
material properties, environmental in-
fluences and operating conditions, in-
cluding the effects of other engine
parts influencing these parameters, are
sufficiently well known and predictable
so that the operating limitations can
be established and maintained for each
engine life-limited part. Applicants
must perform appropriate damage tol-
erance assessments to address the po-
tential for failure from material, man-
ufacturing, and service induced anoma-
lies within the approved life of the
part. Applicants must publish a list of
the life-limited engine parts and the
approved life for each part in the Air-
worthiness Limitations Section of the
Instructions for Continued Airworthi-
ness as required by § 33.4 of this part.
(b) A manufacturing plan that identi-
fies the specific manufacturing con-
straints necessary to consistently
produce each engine life-limited part
with the attributes required by the en-
gineering plan.
(c) A service management plan that
defines in-service processes for mainte-
nance and the limitations to repair for
each engine life-limited part that will
maintain attributes consistent with
those required by the engineering plan.
These processes and limitations will
become part of the Instructions for
Continued Airworthiness.
[Amdt. 33–22, 72 FR 50860, Sept. 4, 2007]
§ 33.71
Lubrication system.
(a)
General. Each lubrication system
must function properly in the flight at-
titudes and atmospheric conditions in
which an aircraft is expected to oper-
ate.
(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 par-
ticles passing through the specified fil-
tering 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 para-
graph (b)(2) of this section.
(4) For each strainer or filter re-
quired by this paragraph, except the
strainer or filter at the oil tank outlet,
there must be means to indicate con-
tamination before it reaches the capac-
ity established in accordance with
paragraph (b)(3) of this section.
(5) Any filter bypass must be de-
signed and constructed so that the re-
lease 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, ex-
cept 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 occurance of contamination of
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718
14 CFR Ch. I (1–1–24 Edition)
§ 33.72
the screen before it reaches the capac-
ity 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 inadvert-
ently fill the oil tank expansion space.
(3) Each recessed oil tank filler con-
nection 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. For an applicant seeking
eligibility for an engine to be installed
on an airplane approved for ETOPS,
the oil tank must be designed to pre-
vent a hazardous loss of oil due to an
incorrectly installed oil tank cap.
(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 ac-
cumulate 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 (in-
cluding 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 must meet the requirements of
§ 33.64.
(10) Leaked or spilled oil may not ac-
cumulate between the tank and the re-
mainder 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 pre-
vent 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 posi-
tion.
(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; Amdt. 33–21, 72 FR 1877, Jan. 16, 2007;
Amdt. 33–27, 73 FR 55437, Sept. 25, 2008; Amdt.
33–27, 73 FR 57235, Oct. 2, 2008]
§ 33.72
Hydraulic actuating systems.
Each hydraulic actuating system
must function properly under all condi-
tions 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 § 33.71.
[Amdt. 33–6, 39 FR 35467, Oct. 1, 1974]
§ 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 over-
temperature, surge, stall, or other det-
rimental factors occurring to the en-
gine 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 oper-
ation requiring control scheduling; and
(b) From the fixed minimum flight
idle power lever position when pro-
vided, 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
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