spaschal on DSK3GDR082PROD with CFR

Federal Aviation Administration, DOT

Section 27.1521

(1) A limit engine torque must be established if the maximum torque that
the engine can exert is greater than - 
(i) The torque that the rotor drive
system is designed to transmit; or
(ii) The torque that the main rotor
assembly is designed to withstand in
showing compliance with Section 27.547(e).
(2) The limit engine torque established under paragraph (e)(1) of this
section may not exceed either torque
specified in paragraph (e)(1)(i) or (ii) of
this section.
(f) Ambient temperature. For turbine
engines, ambient temperature limitations (including limitations for winterization installations, if applicable)
must be established as the maximum
ambient atmospheric temperature at
which compliance with the cooling provisions of SectionSection 27.1041 through 27.1045 is
shown.
(g) Two and one-half-minute OEI power
operation. Unless otherwise authorized,
the use of 21-2-minute OEI power must
be limited to engine failure operation
of multiengine, turbine-powered rotorcraft for not longer than 21-2 minutes
after failure of an engine. The use of
21-2-minute OEI power must also be limited by - 
(1) The maximum rotational speed,
which may not be greater than - 
(i) The maximum value determined
by the rotor design; or
(ii) The maximum demonstrated during the type tests;
(2) The maximum allowable gas temperature; and
(3) The maximum allowable torque.
(h) Thirty-minute OEI power operation.
Unless otherwise authorized, the use of
30-minute OEI power must be limited
to multiengine, turbine-powered rotorcraft for not longer than 30 minutes
after failure of an engine. The use of 30minute OEI power must also be limited
by - 
(1) The maximum rotational speed,
which may not be greater than - 
(i) The maximum value determined
by the rotor design; or
(ii) The maximum value demonstrated during the type tests;
(2) The maximum allowable gas temperature; and
(3) The maximum allowable torque.
(i) Continuous OEI power operation.
Unless otherwise authorized, the use of

continuous OEI power must be limited
to multiengine, turbine-powered rotorcraft for continued flight after failure
of an engine. The use of continuous
OEI power must also be limited by - 
(1) The maximum rotational speed,
which may not be greater than - 
(i) The maximum value determined
by the rotor design; or
(ii) The maximum value demonstrated during the type tests;
(2) The maximum allowable gas temperature; and
(3) The maximum allowable torque.
(j) Rated 30-second OEI power operation. Rated 30-second OEI power is
permitted only on multiengine, turbine-powered rotorcraft, also certificated for the use of rated 2-minute OEI
power, and can only be used for continued operation of the remaining engine(s) after a failure or precautionary
shutdown of an engine. It must be
shown that following application of 30second OEI power, any damage will be
readily detectable by the applicable inspections and other related procedures
furnished in accordance with Section
A27.4 of appendix A of this part and
Section A33.4 of appendix A of part 33.
The use of 30-second OEI power must be
limited to not more than 30 seconds for
any period in which that power is used,
and by - 
(1) The maximum rotational speed,
which may not be greater than - 
(i) The maximum value determined
by the rotor design; or
(ii) The maximum value demonstrated during the type tests;
(2) The maximum allowable gas temperature; and
(3) The maximum allowable torque.
(k) Rated 2-minute OEI power operation. Rated 2-minute OEI power is permitted only on multiengine, turbinepowered rotorcraft, also certificated
for the use of rated 30-second OEI
power, and can only be used for continued operation of the remaining engine(s) after a failure or precautionary
shutdown of an engine. It must be
shown that following application of 2minute OEI power, any damage will be
readily detectable by the applicable inspections and other related procedures
furnished in accordance with Section
A27.4 of appendix A of this part and
Section A33.4 of appendix A of part 33.

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VerDate Sep<11>2014

12:50 Apr 30, 2019

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