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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 

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