735 

Federal Aviation Administration, DOT 

§ 33.95 

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-

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 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 

(c) In lieu of compliance with para-

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] 

§ 33.94

Blade containment and rotor 

unbalance tests. 

(a) Except as provided in paragraph 

(b) of this section, it must be dem-
onstrated by engine tests that the en-
gine is capable of containing damage 
without catching fire and without fail-
ure of its mounting attachments when 
operated for at least 15 seconds, unless 
the resulting engine damage induces a 
self shutdown, after each of the fol-
lowing events: 

(1) Failure of the most critical com-

pressor or fan blade while operating at 

maximum permissible r.p.m. The blade 
failure must occur at the outermost re-
tention groove or, for integrally-bladed 
rotor discs, at least 80 percent of the 
blade must fail. 

(2) Failure of the most critical tur-

bine blade while operating at max-
imum permissible r.p.m. The blade fail-
ure must occur at the outermost reten-
tion groove or, for integrally-bladed 
rotor discs, at least 80 percent of the 
blade must fail. The most critical tur-
bine blade must be determined by con-
sidering turbine blade weight and the 
strength of the adjacent turbine case 
at case temperatures and pressures as-
sociated with operation at maximum 
permissible r.p.m. 

(b) Analysis based on rig testing, 

component testing, or service experi-
ence may be substitute for one of the 
engine tests prescribed in paragraphs 
(a)(1) and (a)(2) of this section if— 

(1) That test, of the two prescribed, 

produces the least rotor unbalance; and 

(2) The analysis is shown to be equiv-

alent to the test. 

(Secs. 313(a), 601, and 603, Federal Aviation 
Act of 1958 (49 U.S.C. 1354(a), 1421, and 1423); 
and 49 U.S.C. 106(g) Revised, Pub. L. 97–449, 
Jan. 12, 1983) 

[Amdt. 33–10, 49 FR 6854, Feb. 23, 1984] 

§ 33.95

Engine-propeller systems tests. 

If the engine is designed to operate 

with a propeller, the following tests 
must be made with a representative 
propeller installed by either including 
the tests in the endurance run or oth-
erwise performing them in a manner 
acceptable to the Administrator: 

(a) Feathering operation: 25 cycles. 
(b) Negative torque and thrust sys-

tem operation: 25 cycles from rated 
maximum continuous power. 

(c) Automatic decoupler operation: 25 

cycles from rated maximum contin-
uous power (if repeated decoupling and 
recoupling in service is the intended 
function of the device). 

(d) Reverse thrust operation: 175 cy-

cles from the flight-idle position to full 
reverse and 25 cycles at rated max-
imum continuous power from full for-
ward to full reverse thrust. At the end 
of each cycle the propeller must be op-
erated in reverse pitch for a period of 
30 seconds at the maximum rotational 

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