title-14-part-33-sec33-35

707

Federal Aviation Administration, DOT

§ 33.35

(1) Alert the pilot when the engine is

at the 30-second OEI and the 2-minute
OEI power levels, when the event be-
gins, and when the time interval ex-
pires;

(2) Automatically record each usage

and duration of power at the 30-second
OEI and 2-minute OEI levels;

(3) Alert maintenance personnel in a

positive manner that the engine has
been operated at either or both of the
30-second and 2-minute OEI power lev-
els, and permit retrieval of the re-
corded data; and

(4) Enable routine verification of the

proper operation of the above means.

(d) The means, or the provision for a

means, of paragraphs (c)(2) and (c)(3) of
this section must not be capable of
being reset in flight.

(e) The applicant must make provi-

sion for the installation of instrumen-
tation necessary to ensure operation in
compliance with engine operating limi-
tations. Where, in presenting the safe-
ty analysis, or complying with any
other requirement, dependence is
placed on instrumentation that is not
otherwise mandatory in the assumed
aircraft installation, then the appli-
cant must specify this instrumentation
in the engine installation instructions
and declare it mandatory in the engine
approval documentation.

(f) As part of the System Safety As-

sessment of § 33.28(e), the applicant
must assess the possibility and subse-
quent effect of incorrect fit of instru-
ments, sensors, or connectors. Where
necessary, the applicant must take de-
sign precautions to prevent incorrect
configuration of the system.

(g) The sensors, together with associ-

ated wiring and signal conditioning,
must be segregated, electrically and
physically, to the extent necessary to
ensure that the probability of a fault
propagating from instrumentation and
monitoring functions to control func-
tions, or vice versa, is consistent with
the failure effect of the fault.

(h) The applicant must provide in-

strumentation enabling the flight crew
to monitor the functioning of the tur-
bine cooling system unless appropriate
inspections are published in the rel-
evant manuals and evidence shows
that:

(1) Other existing instrumentation

provides adequate warning of failure or
impending failure;

(2) Failure of the cooling system

would not lead to hazardous engine ef-
fects before detection; or

(3) The probability of failure of the

cooling system is extremely remote.

[Amdt. 33–5, 39 FR 1831, Jan. 15, 1974, as
amended by Amdt. 33–6, 39 FR 35465, Oct. 1,
1974; Amdt. 33–18, 61 FR 31328, June 19, 1996;
Amdt. 33–25, 73 FR 48123, Aug. 18, 2008; Amdt.
33–26, 73 FR 48285, Aug. 19, 2008]

Subpart C—Design and Construc-

tion; Reciprocating Aircraft
Engines

§ 33.31

Applicability.

This subpart prescribes additional de-

sign and construction requirements for
reciprocating aircraft engines.

§ 33.33

Vibration.

The engine must be designed and con-

structed 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 vi-
bration and without imparting exces-
sive vibration forces to the aircraft
structure.

§ 33.34

Turbocharger rotors.

Each turbocharger case must be de-

signed and constructed to be able to
contain fragments of a compressor or
turbine that fails at the highest speed
that is obtainable with normal speed
control devices inoperative.

[Amdt. 33–22, 72 FR 50860, Sept. 4, 2007]

§ 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 com-
plete operating range of the engine
under all flight and atmospheric condi-
tions.

(b) The intake passages of the engine

through which air or fuel in combina-
tion with air passes for combustion
purposes must be designed and con-
structed to minimize the danger of ice
accretion in those passages. The engine
must be designed and constructed to

VerDate Sep<11>2014

09:06 Jun 28, 2024

Jkt 262046

PO 00000

Frm 00717

Fmt 8010

Sfmt 8010

Y:\SGML\262046.XXX

262046

jspears on DSK121TN23PROD with CFR

708

14 CFR Ch. I (1–1–24 Edition)

§ 33.37

permit the use of a means for ice pre-
vention.

tering necessary for protection of the
engine fuel system against foreign par-
ticles in the fuel must be specified. The
applicant must show that foreign par-
ticles passing through the prescribed
filtering means will not critically im-
pair engine fuel system functioning.

(d) Each passage in the induction sys-

tem that conducts a mixture of fuel
and air must be self-draining, to pre-
vent a liquid lock in the cylinders, in
all attitudes that the applicant estab-
lishes as those the engine can have
when the aircraft in which it is in-
stalled 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 in-
jected 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]

§ 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 equiva-
lent in-flight reliability.

§ 33.39

Lubrication system.

(a) The lubrication system of the en-

gine must be designed and constructed
so that it will function properly in all
flight attitudes and atmospheric condi-
tions 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 en-

gine must be designed and constructed
to allow installing a means of cooling
the lubricant.

the atmosphere to preclude leakage of
oil from excessive pressure in the
crankcase.

Subpart D—Block Tests;

Reciprocating Aircraft Engines

§ 33.41

Applicability.

This subpart prescribes the block

tests and inspections for reciprocating
aircraft engines.

§ 33.42

General.

Before each endurance test required

by this subpart, the adjustment setting
and functioning characteristic of each
component having an adjustment set-
ting and a functioning characteristic
that can be established independent of
installation on the engine must be es-
tablished and recorded.

[Amdt. 33–6, 39 FR 35465, Oct. 1, 1974]

§ 33.43

Vibration test.

(a) Each engine must undergo a vi-

bration survey to establish the tor-
sional and bending vibration character-
istics of the crankshaft and the pro-
peller shaft or other output shaft, over
the range of crankshaft speed and en-
gine 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 high-
er. 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 vibra-

tion 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 measure-
ment, the vibration frequency and am-
plitude 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 con-
dition 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