Federal Aviation Administration, DOT

Section 33.49

occur within the endurance limit stress
of the material.
(c) Each accessory drive and mounting attachment must be loaded, with
the loads imposed by each accessory
used only for an aircraft service being
the limit load specified by the applicant 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 conditions under which the engine can be operated 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]

Section 33.45

Calibration tests.

(a) Each engine must be subjected to
the calibration tests necessary to establish its power characteristics and
the conditions for the endurance test
specified in Section 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 essential for engine functioning.
(b) A power check at sea level conditions must be accomplished on the endurance test engine after the endurance test. Any change in power characteristics which occurs during the endurance 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.

spaschal on DSK3GDR082PROD with CFR

[Doc. No. 3025, 29 FR 7453, June 10, 1964, as
amended by Amdt. 33-6, 39 FR 35465, Oct. 1,
1974]

Section 33.47

Detonation test.

Each engine must be tested to establish that the engine can function with-

out detonation throughout its range of
intended conditions of operation.
Section 33.49 Endurance test.
(a) General. Each engine must be subjected to an endurance test that includes a total of 150 hours of operation
(except as provided in paragraph
(e)(1)(iii) of this section) and, depending 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 applicable. The runs must be made in the
order found appropriate by the Administrator for the particular engine being
tested. During the endurance test the
engine power and the crankshaft rotational speed must be kept within Section3
percent of the rated values. During the
runs at rated takeoff power and for at
least 35 hours at rated maximum continuous 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 temperature must be maintained within Section10 degrees F. of the limiting temperature.
An engine that is equipped with a propeller shaft must be fitted for the endurance test with a propeller that
thrust-loads the engine to the maximum thrust which the engine is designed to resist at each applicable operating condition specified in this section. Each accessory drive and mounting 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 engines incorporating a gear-driven singlespeed supercharger. For engines not incorporating a supercharger and for engines incorporating a gear-driven single-speed supercharger the applicant
must conduct the following runs:
(1) A 30-hour run consisting of alternate periods of 5 minutes at rated takeoff power with takeoff speed, and 5
minutes at maximum best economy
cruising power or maximum recommended cruising power.

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