Federal Aviation Administration, DOT

Section 33.49

spaschal on DSK3GDR082PROD with CFR

(9) A 20-hour run consisting of alternate periods in the lower gear ratio of
2 hours at rated maximum continuous
power with maximum continuous
speed, and 2 hours at maximum best
economy cruising power and speed or
at maximum recommended cruising
power.
(10) A 5-hour run in the lower gear
ratio at maximum best economy cruising power and speed or at maximum
recommended cruising power and
speed.
Where simulated altitude test equipment is not available when operating
in the higher gear ratio, the runs may
be made at the observed horsepower obtained with the critical altitude manifold pressure or specified percentages
thereof, and the fuel-air mixtures may
be adjusted to be rich enough to suppress detonation.
(d) Helicopter engines. To be eligible
for use on a helicopter each engine
must either comply with paragraphs
(a) through (j) of Section 29.923 of this chapter, or must undergo the following series of runs:
(1) A 35-hour run consisting of alternate periods of 30 minutes each at
rated takeoff power with takeoff speed,
and at rated maximum continuous
power with maximum continuous
speed.
(2) A 25-hour run consisting of alternate periods of 21-2 hours each at rated
maximum continuous power with maximum continuous speed, and at 70 percent rated maximum continuous power
with maximum continuous speed.
(3) A 25-hour run consisting of alternate periods of 21-2 hours each at rated
maximum continuous power with maximum continuous speed, and at 70 percent rated maximum continuous power
with 80 to 90 percent maximum continuous speed.
(4) A 25-hour run consisting of alternate periods of 21-2 hours each at 30 percent rated maximum continuous power
with takeoff speed, and at 30 percent
rated maximum continuous power with
80 to 90 percent maximum continuous
speed.
(5) A 25-hour run consisting of alternate periods of 21-2 hours each at 80 percent rated maximum continuous power
with takeoff speed, and at either rated
maximum continuous power with 110

percent maximum continuous speed or
at rated takeoff power with 103 percent
takeoff speed, whichever results in the
greater speed.
(6) A 15-hour run at 105 percent rated
maximum continuous power with 105
percent maximum continuous speed or
at full throttle and corresponding
speed at standard sea level carburetor
entrance pressure, if 105 percent of the
rated maximum continuous power is
not exceeded.
(e) Turbosupercharged engines. For engines
incorporating
a
turbosupercharger the following apply except that altitude testing may be simulated provided the applicant shows that
the engine and supercharger are being
subjected to mechanical loads and operating temperatures no less severe
than if run at actual altitude conditions:
(1) For engines used in airplanes the
applicant must conduct the runs specified in paragraph (b) of this section, except - 
(i) The entire run specified in paragraph (b)(1) of this section must be
made at sea level altitude pressure;
(ii) The portions of the runs specified
in paragraphs (b)(2) through (7) of this
section at rated maximum continuous
power must be made at critical altitude pressure, and the portions of the
runs at other power must be made at
8,000 feet altitude pressure; and
(iii) The turbosupercharger used during the 150-hour endurance test must
be run on the bench for an additional 50
hours at the limiting turbine wheel
inlet gas temperature and rotational
speed for rated maximum continuous
power operation unless the limiting
temperature and speed are maintained
during 50 hours of the rated maximum
continuous power operation.
(2) For engines used in helicopters
the applicant must conduct the runs
specified in paragraph (d) of this section, except - 
(i) The entire run specified in paragraph (d)(1) of this section must be
made at critical altitude pressure;
(ii) The portions of the runs specified
in paragraphs (d)(2) and (3) of this section at rated maximum continuous
power must be made at critical altitude pressure and the portions of the

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