(a) For the purpose of this part, the powerplant installation includes
each part of the rotorcraft (other than the main and auxiliary rotor
structures) that --
(1) Is necessary for propulsion;
(2) Affects the control of the major propulsive units; or
(3) Affects the safety of the major propulsive units between normal
inspections or overhauls.
(b) For each powerplant installation --
(1) The installation must comply with --
(i) The installation instructions provided under §33.5 of this chapter;
(ii) The applicable provisions of this subpart.
(2) Each component of the installation must be constructed, arranged,
and installed to ensure its continued safe operation between normal
inspections or overhauls for the range of temperature and altitude for
which approval is requested.
(3) Accessibility must be provided to allow any inspection and
maintenance necessary for continued airworthiness; and
(4) Electrical interconnections must be provided to prevent differences
of potential between major components of the installation and the rest of
(5) Axial and radial expansion of turbine engines may not affect the
safety of the installation.
(6) Design precautions must be taken to minimize the possibility of
incorrect assembly of components and equipment essential to safe operation
of the rotorcraft, except where operation with the incorrect assembly can
be shown to be extremely improbable.
(c) For each powerplant and auxiliary power unit installation, it must
be established that no single failure or malfunction or probable
combination of failures will jeopardize the safe operation of the
rotorcraft except that the failure of structural elements need not be
considered if the probability of any such failure is extremely remote.
(d) Each auxiliary power unit installation must meet the applicable
provisions of this subpart. (Secs. 313(a), 601, 603, 604, Federal
Aviation Act of 1958 (49 U.S.C. 1354(a), 1421, 1423, 1424), sec. 6(c),
Dept. of Transportation Act (49 U.S.C. 1655(c)))