776
14 CFR Ch. I (1–1–14 Edition)
§ 29.923
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 30-
second 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 sta-
bilized 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 con-
ducted on a bench test, the test se-
quence must be conducted following
stabilization at take-off power.
(ii) For the purpose of this para-
graph, 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 re-
peated use of this power or would re-
sult in premature engine removals dur-
ing the test. The loads, the vibration
frequency, and the methods of applica-
tion 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 contin-
uous run. Three hours of continuous op-
eration 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, max-
imum left thrust component, and max-
imum right thrust component, except
that the control movements need not
produce loads or blade flapping motion
exceeding the maximum loads of mo-
tions encountered in flight.
(2) The directional controls must be
operated at a minimum of 15 times
each hour through the control ex-
tremes of maximum right turning
torque, neutral torque as required by
the power applied to the main rotor,
and maximum left turning torque.
(3) Each maximum control position
must be held for at least 10 seconds,
and the rate of change of control posi-
tion must be at least as rapid as that
for normal operation.
(d)
Endurance tests; 90 percent of max-
imum continuous run. One hour of con-
tinuous operation at 90 percent of max-
imum continuous torque and the max-
imum speed for use with 90 percent of
maximum continuous torque must be
conducted.
(e)
Endurance tests; 80 percent of max-
imum continuous run. One hour of con-
tinuous operation at 80 percent of max-
imum continuous torque and the min-
imum speed for use with 80 percent of
maximum continuous torque must be
conducted.
(f)
Endurance tests; 60 percent of max-
imum continuous run. Two hours or, for
helicopters for which the use of either
30-minute OEI power or continuous OEI
power is requested, 1 hour of contin-
uous operation at 60 percent of max-
imum continuous torque and the min-
imum speed for use with 60 percent of
maximum continuous torque must be
conducted.
(g)
Endurance tests; engine malfunc-
tioning run. It must be determined
whether malfunctioning of compo-
nents, such as the engine fuel or igni-
tion systems, or whether unequal en-
gine power can cause dynamic condi-
tions detrimental to the drive system.
If so, a suitable number of hours of op-
eration must be accomplished under
those conditions, 1 hour of which must
be included in each cycle, and the re-
maining hours of which must be ac-
complished at the end of the 20 cycles.
If no detrimental condition results, an
additional hour of operation in compli-
ance with paragraph (b) of this section
must be conducted in accordance with
the run schedule of paragraph (b)(1) of
this section without consideration of
paragraph (b)(2) of this section.
(h)
Endurance tests; overspeed run. One
hour of continuous operation must be
conducted at maximum continuous
torque and the maximum power-on
VerDate Mar<15>2010
10:12 Mar 18, 2014
Jkt 232046
PO 00000
Frm 00786
Fmt 8010
Sfmt 8010
Y:\SGML\232046.XXX
232046
pmangrum on DSK3VPTVN1PROD with CFR