spaschal on DSK3GDR082PROD with CFR

Federal Aviation Administration, DOT

Section 29.923

(ii) Absorbed by the rotors to be approved for the rotorcraft.
(b) Endurance tests; takeoff run. The
takeoff run must be conducted as follows:
(1) Except as prescribed in paragraphs (b)(2) and (b)(3) of this section,
the takeoff torque run must consist of
1 hour of alternate runs of 5 minutes at
takeoff torque and the maximum speed
for use with takeoff torque, and 5 minutes at as low an engine idle speed as
practicable. The engine must be declutched from the rotor drive system,
and the rotor brake, if furnished and so
intended, must be applied during the
first minute of the idle run. During the
remaining 4 minutes of the idle run,
the clutch must be engaged so that the
engine drives the rotors at the minimum practical r.p.m. The engine and
the rotor drive system must be accelerated at the maximum rate. When declutching the engine, it must be decelerated rapidly enough to allow the operation of the overrunning clutch.
(2) For helicopters for which the use
of a 21-2-minute OEI rating is requested,
the takeoff run must be conducted as
prescribed in paragraph (b)(1) of this
section, except for the third and sixth
runs for which the takeoff torque and
the maximum speed for use with takeoff torque are prescribed in that paragraph. For these runs, the following
apply:
(i) Each run must consist of at least
one period of 21-2 minutes with takeoff
torque and the maximum speed for use
with takeoff torque on all engines.
(ii) Each run must consist of at least
one period, for each engine in sequence,
during which that engine simulates a
power failure and the remaining engines are run at the 21-2-minute OEI
torque and the maximum speed for use
with 21-2-minute OEI torque for 21-2 minutes.
(3) For multiengine, turbine-powered
rotorcraft for which the use of 30-second/2-minute OEI power is requested,
the takeoff run must be conducted as
prescribed in paragraph (b)(1) of this
section except for the following:
(i) Immediately following any one 5minute power-on run required by paragraph (b)(1) of this section, simulate a
failure for each power source in turn,
and apply the maximum torque and the

maximum speed for use with 30-second
OEI power to the remaining affected
drive system power inputs for not less
than 30 seconds. Each application of 30second OEI power must be followed by
two applications of the maximum
torque and the maximum speed for use
with the 2 minute OEI power for not
less than 2 minutes each; the second
application must follow a period at stabilized continuous or 30 minute OEI
power (whichever is requested by the
applicant). At least one run sequence
must be conducted from a simulated
 - flight idle -  condition. When conducted on a bench test, the test sequence must be conducted following
stabilization at take-off power.
(ii) For the purpose of this paragraph, an affected power input includes
all parts of the rotor drive system
which can be adversely affected by the
application of higher or asymmetric
torque and speed prescribed by the
test.
(iii) This test may be conducted on a
representative bench test facility when
engine limitations either preclude repeated use of this power or would result in premature engine removals during the test. The loads, the vibration
frequency, and the methods of application to the affected rotor drive system
components must be representative of
rotorcraft conditions. Test components
must be those used to show compliance
with the remainder of this section.
(c) Endurance tests; maximum continuous run. Three hours of continuous operation at maximum continuous torque
and the maximum speed for use with
maximum continuous torque must be
conducted as follows:
(1) The main rotor controls must be
operated at a minimum of 15 times
each hour through the main rotor pitch
positions of maximum vertical thrust,
maximum forward thrust component,
maximum aft thrust component, maximum left thrust component, and maximum right thrust component, except
that the control movements need not
produce loads or blade flapping motion
exceeding the maximum loads of motions encountered in flight.
(2) The directional controls must be
operated at a minimum of 15 times
each hour through the control extremes of maximum right turning

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