ED Decision 2003/15/RM
(a) For the purpose of this CS-27, 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) 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;
(2) Accessibility must be provided to allow any inspection and maintenance necessary for continued airworthiness;
(3) Electrical interconnections must be provided to prevent differences of potential between major components of the installation and the rest of the rotorcraft;
(4) Axial and radial expansion of turbine engines may not affect the safety of the installation; and
(5) Design precautions must be taken to minimise 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) The installation must comply with:
(1) The installation instructions provided under CS-E; and
(2) The applicable provisions of this Subpart.
ED Decision 2007/013/R
(a) (Reserved)
(b) Engine or drive system cooling fan blade protection.
(1) If an engine or rotor drive system cooling fan is installed, there must be means to protect the rotorcraft and allow a safe landing if a fan blade fails. This must be shown by showing that:
(i) The fan blades are contained in case of failure;
(ii) Each fan is located so that a failure will not jeopardise safety; or
(iii) Each fan blade can withstand an ultimate load of 1.5 times the centrifugal force resulting from operation limited by the following:
(A) For fans driven directly by the engine:
(1) The terminal engine rpm under uncontrolled conditions; or
(2) An overspeed limiting device.
(B) For fans driven by the rotor drive system the maximum rotor drive system rotational speed to be expected in service, including transients.
(2) Unless a fatigue evaluation under CS 27.571 is conducted, it must be shown that cooling fan blades are not operating at resonant conditions within the operating limits of the rotorcraft.
(c) Turbine engine installation. For turbine engine installations, the powerplant systems associated with engine control devices, systems, and instrumentation must be designed to give reasonable assurance that those engine operating limitations that adversely affect turbine rotor structural integrity will not be exceeded in service.
(d) Restart capability. A means to restart any engine in flight must be provided.
(1) Except for the in-flight shutdown of all engines, engine restart capability must be demonstrated throughout a flight envelope for the rotorcraft.
(2) Following the in-flight shutdown of all engines, in-flight engine restart capability must be provided.
[Amdt. No.: 27/1]
ED Decision 2003/15/RM
(a) Each engine must be installed to prevent the harmful vibration of any part of the engine or rotorcraft.
(b) The addition of the rotor and the rotor drive system to the engine may not subject the principal rotating parts of the engine to excessive vibration stresses. This must be shown by a vibration investigation.
(c) No part of the rotor drive system may be subjected to excessive vibration stresses.