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14 CFR Ch. I (1–1–19 Edition) 

§ 33.90 

(iii) An intermediate value for bleed 

air and power extraction representa-
tive of that which might be used as a 
maximum for aircraft during approach 
to a landing. 

(4) If testing facilities are not avail-

able, the determination of power ex-
traction required in paragraph (a)(3)(ii) 
and (iii) of this section may be accom-
plished through appropriate analytical 
means. 

(b) The operation test must include 

all testing found necessary by the Ad-
ministrator to demonstrate that the 
engine has safe operating characteris-
tics 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] 

§ 33.90

Initial maintenance inspection 

test. 

Each applicant, except an applicant 

for an engine being type certificated 
through amendment of an existing type 
certificate or through supplemental 
type certification procedures, must 
complete one of the following tests on 
an engine that substantially conforms 
to the type design to establish when 
the initial maintenance inspection is 
required: 

(a) An approved engine test that sim-

ulates the conditions in which the en-
gine is expected to operate in service, 
including typical start-stop cycles. 

(b) An approved engine test con-

ducted in accordance with § 33.201 (c) 
through (f). 

[Doc. No. FAA–2002–6717, 72 FR 1877, Jan. 16, 
2007] 

§ 33.91

Engine system and component 

tests. 

(a) For those systems or components 

that cannot be adequately substan-
tiated in accordance with endurance 
testing of § 33.87, the applicant must 
conduct additional tests to dem-
onstrate that the systems or compo-
nents are able to perform the intended 
functions in all declared environmental 
and operating conditions. 

(b) Temperature limits must be es-

tablished for those components that re-
quire temperature controlling provi-
sions in the aircraft installation to as-

sure satisfactory functioning, reli-
ability, and durability. 

(c) Each unpressurized hydraulic 

fluid tank may not fail or leak when 
subjected to a maximum operating 
temperature and an internal pressure 
of 5 p.s.i., and each pressurized hydrau-
lic fluid tank must meet the require-
ments of § 33.64. 

(d) For an engine type certificated 

for use in supersonic aircraft, the sys-
tems, safety devices, and external com-
ponents that may fail because of oper-
ation at maximum and minimum oper-
ating temperatures must be identified 
and tested at maximum and minimum 
operating temperatures and while tem-
perature and other operating condi-
tions 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; Amdt. 33–26, 73 FR 48285, Aug. 19, 2008; 
Amdt. 33–27, 73 FR 55437, Sept. 25, 2008; Amdt. 
33–27, 73 FR 57235, Oct. 2, 2008] 

§ 33.92

Rotor locking tests. 

If continued rotation is prevented by 

a means to lock the rotor(s), the engine 
must be subjected to a test that in-
cludes 25 operations of this means 
under the following conditions: 

(a) The engine must be shut down 

from rated maximum continuous 
thrust or power; and 

(b) The means for stopping and lock-

ing the rotor(s) must be operated as 
specified in the engine operating in-
structions while being subjected to the 
maximum torque that could result 
from continued flight in this condition; 
and 

(c) Following rotor locking, the 

rotor(s) must be held stationary under 
these conditions for five minutes for 
each of the 25 operations. 

[Doc. No. 28107, 61 FR 28433, June 4, 1996] 

§ 33.93

Teardown inspection. 

(a) After completing the endurance 

testing of § 33.87 (b), (c), (d), (e), or (g) 
of this part, each engine must be com-
pletely disassembled, and 

(1) Each component having an adjust-

ment setting and a functioning char-
acteristic that can be established inde-
pendent of installation on the engine 
must retain each setting and func-
tioning characteristic within the limits 

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