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Federal Aviation Administration, DOT 

§ 33.201 

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 



: 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 

(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 
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 

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