709
Federal Aviation Administration, DOT
§ 33.49
occur within the endurance limit stress
of the material.
(c) Each accessory drive and mount-
ing attachment must be loaded, with
the loads imposed by each accessory
used only for an aircraft service being
the limit load specified by the appli-
cant for the drive or attachment point.
(d) The vibration survey described in
paragraph (a) of this section must be
repeated with that cylinder not firing
which has the most adverse vibration
effect, in order to establish the condi-
tions under which the engine can be op-
erated safely in that abnormal state.
However, for this vibration survey, the
engine speed range need only extend
from idle to the maximum desired
takeoff speed, and compliance with
paragraph (b) of this section need not
be shown.
[Amdt. 33–6, 39 FR 35465, Oct. 1, 1974, as
amended by Amdt. 33–10, 49 FR 6851, Feb. 23,
1984]
§ 33.45
Calibration tests.
(a) Each engine must be subjected to
the calibration tests necessary to es-
tablish its power characteristics and
the conditions for the endurance test
specified in § 33.49. The results of the
power characteristics calibration tests
form the basis for establishing the
characteristics of the engine over its
entire operating range of crankshaft
rotational speeds, manifold pressures,
fuel/air mixture settings, and altitudes.
Power ratings are based upon standard
atmospheric conditions with only those
accessories installed which are essen-
tial for engine functioning.
(b) A power check at sea level condi-
tions must be accomplished on the en-
durance test engine after the endur-
ance test. Any change in power charac-
teristics which occurs during the en-
durance test must be determined.
Measurements taken during the final
portion of the endurance test may be
used in showing compliance with the
requirements of this paragraph.
[Doc. No. 3025, 29 FR 7453, June 10, 1964, as
amended by Amdt. 33–6, 39 FR 35465, Oct. 1,
1974]
§ 33.47
Detonation test.
Each engine must be tested to estab-
lish that the engine can function with-
out detonation throughout its range of
intended conditions of operation.
§ 33.49
Endurance test.
(a)
General. Each engine must be sub-
jected to an endurance test that in-
cludes a total of 150 hours of operation
(except as provided in paragraph
(e)(1)(iii) of this section) and, depend-
ing upon the type and contemplated
use of the engine, consists of one of the
series of runs specified in paragraphs
(b) through (e) of this section, as appli-
cable. The runs must be made in the
order found appropriate by the Admin-
istrator for the particular engine being
tested. During the endurance test the
engine power and the crankshaft rota-
tional speed must be kept within
±
3
percent of the rated values. During the
runs at rated takeoff power and for at
least 35 hours at rated maximum con-
tinuous power, one cylinder must be
operated at not less than the limiting
temperature, the other cylinders must
be operated at a temperature not lower
than 50 degrees F. below the limiting
temperature, and the oil inlet tempera-
ture must be maintained within
±
10 de-
grees F. of the limiting temperature.
An engine that is equipped with a pro-
peller shaft must be fitted for the en-
durance test with a propeller that
thrust-loads the engine to the max-
imum thrust which the engine is de-
signed to resist at each applicable op-
erating condition specified in this sec-
tion. Each accessory drive and mount-
ing attachment must be loaded. During
operation at rated takeoff power and
rated maximum continuous power, the
load imposed by each accessory used
only for an aircraft service must be the
limit load specified by the applicant
for the engine drive or attachment
point.
(b)
Unsupercharged engines and en-
gines incorporating a gear-driven single-
speed supercharger. For engines not in-
corporating a supercharger and for en-
gines incorporating a gear-driven sin-
gle-speed supercharger the applicant
must conduct the following runs:
(1) A 30-hour run consisting of alter-
nate periods of 5 minutes at rated take-
off power with takeoff speed, and 5
minutes at maximum best economy
cruising power or maximum rec-
ommended cruising power.
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