874
14 CFR Ch. I (1–1–14 Edition)
§ 33.87
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
burning thrust augmentor augmenta-
tion position if additional time to con-
firm ignition is necessary.
(ii) During the runs at any rated aug-
mented thrust the hydraulic fluid tem-
perature must be maintained at the
limiting temperature except where the
test periods are not long enough to
allow stabilization.
(iii) During the simulated supersonic
runs the fuel temperature and induc-
tion air temperature may not be less
than the limiting temperature.
(iv) The endurance test must be con-
ducted with the fuel burning thrust
augmentor installed, with the primary
and secondary exhaust nozzles in-
stalled, and with the variable area ex-
haust nozzles operated during each run
according to the methods specified in
complying with § 33.5(b).
(v) During the runs at thrust settings
for maximum continuous thrust and
percentages thereof, the engine must
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