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738 

14 CFR Ch. I (1–1–24 Edition) 

§ 33.97 

performed on the same engine, but this 
engine need not be the same engine 
used for the tests required by § 33.87. 

(e) The tests required by paragraphs 

(a), (b), and (c) of this section must be 
followed by engine disassembly to the 
extent necessary to show compliance 
with the requirements of § 33.93(a) and 
§ 33.93(b). 

[Amdt. 33–11, 51 FR 10346, Mar. 25, 1986] 

§ 33.97

Thrust reversers. 

(a) If the engine incorporates a re-

verser, the endurance, calibration, op-
eration, and vibration tests prescribed 
in this subpart must be run with the 
reverser installed. In complying with 
this section, the power control lever 
must be moved from one extreme posi-
tion to the other in not more than one 
second except, if regimes of control op-
erations are incorporated necessitating 
scheduling of the power-control lever 
motion in going from one extreme posi-
tion to the other, a longer period of 
time is acceptable but not more than 
three seconds. In addition, the test pre-
scribed in paragraph (b) of this section 
must be made. This test may be sched-
uled as part of the endurance run. 

(b) 175 reversals must be made from 

flight-idle forward thrust to maximum 
reverse thrust and 25 reversals must be 
made from rated takeoff thrust to max-
imum reverse thrust. After each rever-
sal the reverser must be operated at 
full reverse thrust for a period of one 
minute, except that, in the case of a re-
verser intended for use only as a brak-
ing means on the ground, the reverser 
need only be operated at full reverse 
thrust for 30 seconds. 

[Doc. No. 3025, 29 FR 7453, June 10, 1964, as 
amended by Amdt. 33–3, 32 FR 3737, Mar. 4, 
1967; Amdt. No. 33–35, 87 FR 75711, Dec. 9, 
2022; 88 FR 2813, Jan. 18, 2023] 

§ 33.99

General conduct of block tests. 

(a) Each applicant may, in making a 

block test, use separate engines of 
identical design and construction in 
the vibration, calibration, endurance, 
and operation tests, except that, if a 
separate engine is used for the endur-
ance test it must be subjected to a cali-
bration check before starting the en-
durance test. 

(b) Each applicant may service and 

make minor repairs to the engine dur-
ing the block tests in accordance with 
the service and maintenance instruc-
tions submitted in compliance with 
§ 33.4. If the frequency of the service is 
excessive, or the number of stops due 
to engine malfunction is excessive, or a 
major repair, or replacement of a part 
is found necessary during the block 
tests or as the result of findings from 
the teardown inspection, the engine or 
its parts must be subjected to any addi-
tional tests the Administrator finds 
necessary. 

(c) Each applicant must furnish all 

testing facilities, including equipment 
and competent personnel, to conduct 
the block tests. 

[Doc. No. 3025, 29 FR 7453, June 10, 1964, as 
amended by Amdt. 33–6, 39 FR 35470, Oct. 1, 
1974; Amdt. 33–9, 45 FR 60181, Sept. 11, 1980] 

Subpart G—Special Requirements: 

Turbine Aircraft Engines 

S

OURCE

: Docket No. FAA–2002–6717, 72 FR 

1877, Jan. 16, 2007, unless otherwise noted. 

§ 33.201

Design and test requirements 

for Early ETOPS eligibility. 

An applicant seeking type design ap-

proval for an engine to be installed on 
a two-engine airplane approved for 
ETOPS without the service experience 
specified in part 25, appendix K, K25.2.1 
of this chapter, must comply with the 
following: 

(a) The engine must be designed 

using a design quality process accept-
able to the FAA, that ensures the de-
sign features of the engine minimize 
the occurrence of failures, malfunc-
tions, defects, and maintenance errors 
that could result in an IFSD, loss of 
thrust control, or other power loss. 

(b) The design features of the engine 

must address problems shown to result 
in an IFSD, loss of thrust control, or 
other power loss in the applicant’s 
other relevant type designs approved 
within the past 10 years, to the extent 
that adequate service data is available 
within that 10-year period. An appli-
cant without adequate service data 
must show experience with and knowl-
edge of problem mitigating design 
practices equivalent to that gained 

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739 

Federal Aviation Administration, DOT 

§ 33.201 

from actual service experience in a 
manner acceptable to the FAA. 

(c) Except as specified in paragraph 

(f) of this section, the applicant must 
conduct a simulated ETOPS mission 
cyclic endurance test in accordance 
with an approved test plan on an en-
gine that substantially conforms to the 
type design. The test must: 

(1) Include a minimum of 3,000 rep-

resentative service start-stop mission 
cycles and three simulated diversion 
cycles at maximum continuous thrust 
or power for the maximum diversion 
time for which ETOPS eligibility is 
sought. Each start-stop mission cycle 
must include the use of take-off, climb, 
cruise, descent, approach, and landing 
thrust or power and the use of thrust 
reverse (if applicable). The diversions 
must be evenly distributed over the du-
ration of the test. The last diversion 
must be conducted within 100 cycles of 
the completion of the test. 

(2) Be performed with the high speed 

and low speed main engine rotors inde-
pendently unbalanced to obtain a min-
imum of 90 percent of the rec-
ommended field service maintenance 
vibration levels. For engines with three 
main engine rotors, the intermediate 
speed rotor must be independently un-
balanced to obtain a minimum of 90 
percent of the recommended produc-
tion acceptance vibration level. The re-
quired peak vibration levels must be 
verified during a slow acceleration and 
deceleration run of the test engine cov-
ering the main engine rotor operating 
speed ranges. 

(3) Include a minimum of three mil-

lion vibration cycles for each 60 rpm 
incremental step of the typical high- 
speed rotor start-stop mission cycle. 
The test may be conducted using any 
rotor speed step increment from 60 to 
200 rpm provided the test encompasses 
the typical service start-stop cycle 
speed range. For incremental steps 
greater than 60 rpm, the minimum 
number of vibration cycles must be lin-
early increased up to ten million cycles 
for a 200 rpm incremental step. 

(4) Include a minimum of 300,000 vi-

bration cycles for each 60 rpm incre-
mental step of the high-speed rotor ap-
proved operational speed range be-
tween minimum flight idle and cruise 
power not covered by paragraph (c)(3) 

of this section. The test may be con-
ducted using any rotor speed step in-
crement from 60 to 200 rpm provided 
the test encompasses the applicable 
speed range. For incremental steps 
greater than 60 rpm the minimum 
number of vibration cycles must be lin-
early increased up to 1 million for a 200 
rpm incremental step. 

(5) Include vibration surveys at peri-

odic intervals throughout the test. The 
equivalent value of the peak vibration 
level observed during the surveys must 
meet the minimum vibration require-
ment of § 33.201(c)(2). 

(d) Prior to the test required by para-

graph (c) of this section, the engine 
must be subjected to a calibration test 
to document power and thrust charac-
teristics. 

(e) At the conclusion of the testing 

required by paragraph (c) of this sec-
tion, the engine must: 

(1) Be subjected to a calibration test 

at sea-level conditions. Any change in 
power or thrust characteristics must 
be within approved limits. 

(2) Be visually inspected in accord-

ance with the on-wing inspection rec-
ommendations and limits contained in 
the Instructions for Continued Air-
worthiness submitted in compliance 
with § 33.4. 

(3) Be completely disassembled and 

inspected— 

(i) In accordance with the applicable 

inspection recommendations and limits 
contained in the Instructions for Con-
tinued Airworthiness submitted in 
compliance with § 33.4; 

(ii) With consideration of the causes 

of IFSD, loss of thrust control, or other 
power loss identified by paragraph (b) 
of this section; and 

(iii) In a manner to identify wear or 

distress conditions that could result in 
an IFSD, loss of thrust control, or 
other power loss not specifically iden-
tified by paragraph (b) of this section 
or addressed within the Instructions 
for Continued Airworthiness. 

(4) Not show wear or distress to the 

extent that could result in an IFSD, 
loss of thrust control, or other power 
loss within a period of operation before 
the component, assembly, or system 
would likely have been inspected or 
functionally tested for integrity while 
in service. Such wear or distress must 

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740 

14 CFR Ch. I (1–1–24 Edition) 

Pt. 33, App. A 

have corrective action implemented 
through a design change, a change to 
maintenance instructions, or oper-
ational procedures before ETOPS eligi-
bility is granted. The type and fre-
quency of wear and distress that occurs 
during the engine test must be con-
sistent with the type and frequency of 
wear and distress that would be ex-
pected to occur on ETOPS eligible en-
gines. 

(f) An alternative mission cycle en-

durance test that provides an equiva-
lent demonstration of the unbalance 
and vibration specified in paragraph (c) 
of this section may be used when ap-
proved by the FAA. 

(g) For an applicant using the simu-

lated ETOPS mission cyclic endurance 
test to comply with § 33.90, the test 
may be interrupted so that the engine 
may be inspected by an on-wing or 
other method, using criteria acceptable 
to the FAA, after completion of the 
test cycles required to comply with 
§ 33.90(a). Following the inspection, the 
ETOPS test must be resumed to com-
plete the requirements of this section. 

A

PPENDIX

TO

P

ART

33—I

NSTRUCTIONS

 

FOR

C

ONTINUED

A

IRWORTHINESS

 

A

33.1

GENERAL

 

(a) This appendix specifies requirements 

for the preparation of Instructions for Con-
tinued Airworthiness as required by § 33.4. 

(b) The Instructions for Continued Air-

worthiness for each engine must include the 
Instructions for Continued Airworthiness for 
all engine parts. If Instructions for Contin-
ued Airworthiness are not supplied by the 
engine part manufacturer for an engine part, 
the Instructions for Continued Airworthiness 
for the engine must include the information 
essential to the continued airworthiness of 
the engine. 

(c) The applicant must submit to the FAA 

a program to show how changes to the In-
structions for Continued Airworthiness made 
by the applicant or by the manufacturers of 
engine parts will be distributed. 

A

33.2

FORMAT

 

(a) The Instructions for Continued Air-

worthiness must be in the form of a manual 
or manuals as appropriate for the quantity 
of data to be provided. 

(b) The format of the manual or manuals 

must provide for a practical arrangement. 

A

33.3

CONTENT

 

The contents of the manual or manuals 

must be prepared in the English language. 
The Instructions for Continued Airworthi-
ness must contain the following manuals or 
sections, as appropriate, and information: 

(a) 

Engine Maintenance Manual or Section. 

(1) Introduction information that includes an 
explanation of the engine’s features and data 
to the extent necessary for maintenance or 
preventive maintenance. 

(2) A detailed description of the engine and 

its components, systems, and installations. 

(3) Installation instructions, including 

proper procedures for uncrating, 
deinhibiting, acceptance checking, lifting, 
and attaching accessories, with any nec-
essary checks. 

(4) Basic control and operating information 

describing how the engine components, sys-
tems, and installations operate, and informa-
tion describing the methods of starting, run-
ning, testing, and stopping the engine and its 
parts including any special procedures and 
limitations that apply. 

(5) Servicing information that covers de-

tails regarding servicing points, capacities of 
tanks, reservoirs, types of fluids to be used, 
pressures applicable to the various systems, 
locations of lubrication points, lubricants to 
be used, and equipment required for serv-
icing. 

(6) Scheduling information for each part of 

the engine that provides the recommended 
periods at which it should be cleaned, in-
spected, adjusted, tested, and lubricated, and 
the degree of inspection the applicable wear 
tolerances, and work recommended at these 
periods. However, the applicant may refer to 
an accessory, instrument, or equipment 
manufacturer as the source of this informa-
tion if the applicant shows that the item has 
an exceptionally high degree of complexity 
requiring specialized maintenance tech-
niques, test equipment, or expertise. The rec-
ommended overhaul periods and necessary 
cross references to the Airworthiness Limi-
tations section of the manual must also be 
included. In addition, the applicant must in-
clude an inspection program that includes 
the frequency and extent of the inspections 
necessary to provide for the continued air-
worthiness of the engine. 

(7) Troubleshooting information describing 

probable malfunctions, how to recognize 
those malfunctions, and the remedial action 
for those malfunctions. 

(8) Information describing the order and 

method of removing the engine and its parts 
and replacing parts, with any necessary pre-
cautions to be taken. Instructions for proper 
ground handling, crating, and shipping must 
also be included. 

(9) A list of the tools and equipment nec-

essary for maintenance and directions as to 
their method of use. 

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