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14 CFR Ch. I (1–1–19 Edition) 

§ 33.87 

(d), (e) or (g) of this section, the pre-
scribed 6-hour test sequence must be 
conducted 25 times to complete the re-
quired 150 hours of operation. Engines 
for which the 30-second OEI and 2- 
minute OEI ratings are desired must be 
further tested under paragraph (f) of 
this section. The following test re-
quirements apply: 

(1) The runs must be made in the 

order found appropriate by the FAA for 
the particular engine being tested. 

(2) Any automatic engine control 

that is part of the engine must control 
the engine during the endurance test 
except for operations where automatic 
control is normally overridden by man-
ual control or where manual control is 
otherwise specified for a particular test 
run. 

(3) Except as provided in paragraph 

(a)(5) of this section, power or thrust, 
gas temperature, rotor shaft rotational 
speed, and, if limited, temperature of 
external surfaces of the engine must be 
at least 100 percent of the value associ-
ated with the particular engine oper-
ation being tested. More than one test 
may be run if all parameters cannot be 
held at the 100 percent level simulta-
neously. 

(4) The runs must be made using fuel, 

lubricants and hydraulic fluid which 
conform to the specifications specified 
in complying with § 33.7(c). 

(5) Maximum air bleed for engine and 

aircraft services must be used during 
at least one-fifth of the runs, except for 
the test required under paragraph (f) of 
this section, provided the validity of 
the test is not compromised. However, 
for these runs, the power or thrust or 
the rotor shaft rotational speed may be 
less than 100 percent of the value asso-
ciated with the particular operation 
being tested if the FAA finds that the 
validity of the endurance test is not 
compromised. 

(6) Each accessory drive and mount-

ing attachment must be loaded in ac-
cordance with paragraphs (a)(6)(i) and 
(ii) of this section, except as permitted 
by paragraph (a)(6)(iii) of this section 
for the test required under paragraph 
(f) of this section. 

(i) The load imposed by each acces-

sory used only for aircraft service must 
be the limit load specified by the appli-
cant for the engine drive and attach-

ment point during rated maximum con-
tinuous power or thrust and higher 
output. 

(ii) The endurance test of any acces-

sory drive and mounting attachment 
under load may be accomplished on a 
separate rig if the validity of the test 
is confirmed by an approved analysis. 

(iii) The applicant is not required to 

load the accessory drives and mounting 
attachments when running the tests 
under paragraphs (f)(1) through (f)(8) of 
this section if the applicant can sub-
stantiate that there is no significant 
effect on the durability of any acces-
sory drive or engine component. How-
ever, the applicant must add the equiv-
alent engine output power extraction 
from the power turbine rotor assembly 
to the engine shaft output. 

(7) During the runs at any rated 

power or thrust the gas temperature 
and the oil inlet temperature must be 
maintained at the limiting tempera-
ture except where the test periods are 
not longer than 5 minutes and do not 
allow stabilization. At least one run 
must be made with fuel, oil, and hy-
draulic fluid at the minimum pressure 
limit and at least one run must be 
made with fuel, oil, and hydraulic fluid 
at the maximum pressure limit with 
fluid temperature reduced as necessary 
to allow maximum pressure to be at-
tained. 

(8) If the number of occurrences of ei-

ther transient rotor shaft overspeed, 
transient gas overtemperature or tran-
sient engine overtorque is limited, that 
number of the accelerations required 
by paragraphs (b) through (g) of this 
section must be made at the limiting 
overspeed, overtemperature or over-
torque. If the number of occurrences is 
not limited, half the required accelera-
tions must be made at the limiting 
overspeed, overtemperature or over-
torque. 

(9) For each engine type certificated 

for use on supersonic aircraft the fol-
lowing additional test requirements 
apply: 

(i) To change the thrust setting, the 

power control lever must be moved 
from the initial position to the final 
position in not more than one second 
except for movements into the fuel 

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