title-14-part-33-sec33-91

735

Federal Aviation Administration, DOT

§ 33.91

starts may be made at any time, in-
cluding the period of endurance test-
ing.

[Doc. No. 3025, 29 FR 7453, June 10, 1964, as
amended by Amdt. 33–3, 32 FR 3737, Mar. 4,
1967; Amdt. 33–6, 39 FR 35468, Oct. 1, 1974;
Amdt. 33–10, 49 FR 6853, Feb. 23, 1984; Amdt.
33–12, 53 FR 34220, Sept. 2, 1988; Amdt. 33–18,
61 FR 31328, June 19, 1996; Amdt. 33–25, 73 FR
48123, Aug. 18, 2008; Amdt. 33–30, 74 FR 45311,
Sept. 2, 2009; Amdt. 33–32, 77 FR 22187, Apr.
13, 2012]

§ 33.88

Engine overtemperature test.

(a) Each engine must run for 5 min-

utes at maximum permissible rpm with
the gas temperature at least 75

F (42

C) higher than the maximum rating’s

steady-state operating limit, excluding
maximum values of rpm and gas tem-
perature associated with the 30-second
OEI and 2-minute OEI ratings. Fol-
lowing this run, the turbine assembly
must be within serviceable limits.

(b) In addition to the test require-

ments in paragraph (a) of this section,
each engine for which 30-second OEI
and 2-minute OEI ratings are desired,
that incorporates a means for auto-
matic temperature control within its
operating limitations in accordance
with § 33.28(k), must run for a period of
4 minutes at the maximum power-on
rpm with the gas temperature at least
35

F (19

C) higher than the maximum

operating limit at 30-second OEI rat-
ing. Following this run, the turbine as-
sembly may exhibit distress beyond the
limits for an overtemperature condi-
tion provided the engine is shown by
analysis or test, as found necessary by
the FAA, to maintain the integrity of
the turbine assembly.

used for each test condition.

[Doc. No. 26019, 61 FR 31329, June 19, 1996, as
amended by Amdt. 33–25, 73 FR 48124, Aug. 18,
2008; Amdt. 33–26, 73 FR 48285, Aug. 19, 2008]

§ 33.89

Operation test.

(a) The operation test must include

testing found necessary by the Admin-
istrator to demonstrate—

(1) Starting, idling, acceleration,

overspeeding, ignition, functioning of
the propeller (if the engine is des-
ignated to operate with a propeller);

(2) Compliance with the engine re-

sponse requirements of § 33.73; and

(3) The minimum power or thrust re-

sponse time to 95 percent rated takeoff
power or thrust, from power lever posi-
tions 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 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

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14 CFR Ch. I (1–1–24 Edition)

§ 33.92

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.

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

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
that were established and recorded at
the beginning of the test; and

(2) Each engine part must conform to

the type design and be eligible for in-
corporation into an engine for contin-
ued operation, in accordance with in-
formation submitted in compliance
with § 33.4.

(b) After completing the endurance

testing of § 33.87(f), each engine must be
completely disassembled, and

(1) Each component having an adjust-

(2) Each engine may exhibit deterio-

ration in excess of that permitted in
paragraph (a)(2) of this section, includ-
ing some engine parts or components
that may be unsuitable for further use.
The applicant must show by inspec-
tion, analysis, test, or by any combina-
tion thereof as found necessary by the
FAA, that structural integrity of the
engine is maintained; or

graph (b) of this section, each engine
for which the 30-second OEI and 2-
minute OEI ratings are desired, may be
subjected to the endurance testing of
§§ 33.87 (b), (c), (d), or (e) of this part,
and followed by the testing of § 33.87(f)
without intervening disassembly and
inspection. However, the engine must
comply with paragraph (a) of this sec-
tion after completing the endurance
testing of § 33.87(f).

[Doc. No. 26019, 61 FR 31329, June 19, 1996, as
amended by Amdt. 33–25, 73 FR 48124, Aug. 18,
2008]