9.2.1 The design of the engine should be such
that:
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(a) the power output can be controlled within
the approved limits;
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(b) the probability of an overspeed leading to
hazard of the craft or occupants is extremely remotefootnote;
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(c) safety devices do not cause complete engine
shut-down without prior warning, except where it is essential.
9.2.2 The engine and its mountings should be of
adequate strength and stiffness to enable it to withstand, when suitably
supported, the most adverse combination of loads without exceeding
acceptable stress levels for the material concerned, which should
include:
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(a) loads arising from normal operation of the
engine and reasonably probable (see Note) failure conditions;
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(b) vibration loads likely to occur under normal
and anticipated fault conditions agreed to by the Administration;
and
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(c) inertia and gyroscopic loads.
9.2.3 Each engine should be provided with:
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(a) an emergency overspeed shut-down device connected,
where possible, directly to the engine shaft; and
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(b) at least two means for stopping the engine
under any operating conditions.
9.2.4 The major components of the engine should
have adequate strength to withstand both the thermal and dynamic conditions
of normal operation and any excessive thermal and dynamic conditions
that may result from malfunction of the engine. The engine should
not be damaged by a limited operation at a speed or at temperatures
exceeding the normal values but within the range of the protective
devices. Such operation should be considered in determining the service
life of the engine.
9.2.5 The design should be such as to avoid the
risk of major rupture of casings in the event of a local failure of,
or consequent to, local damage to the casing. Particular consideration
should be given to those casings which are subjected to high stress
due to internal pressure.
9.2.6 The design of the engine should be such
as to minimize the risk of fire or explosion and to enable compliance
with the fire precaution requirements of Chapter
7.
9.2.7 Provision should be made to drain all excess
fuel and oil to a safe position so as to avoid a fire hazard.
9.2.8 Whenever practical, the integrity of the
engine should not be unduly affected by the failure of components
driven by it.
9.2.9 Reasonable provision should be made in engines
for the connexion of adequate instrumentation to enable the crew to
monitor engine operation and assess trends towards unsafe conditions.
The overall limits of accuracy required of any instruments to be fitted
should be stated.
9.2.10 The Administration should be satisfied
in respect of any engine installed in a craft, that
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(a) the probability of a directly hazardous failure
(having regard to the position and protection afforded by the installation)
is extremely remotefootnote; and
-
(b) the probability of loss of power is acceptably
low having regard to the duty of the craft and the duty of the engine
in it.
The Administration may take into account tests, investigations
and operating experience on other engines of the type or related types
in deciding on the evidence needed in the particular application.
9.2.11 Ventilation arrangements to engine spaces
should ensure:
9.2.12 Measures should be taken to reduce engine
noise and vibration in machinery spaces so that they are kept within
acceptable levels as determined by the Administration having regard
to the need for entry to the space during operation. If this noise
cannot be sufficiently reduced, the source of excessive noise should
be suitably insulated and isolated or a refuge from noise should be
provided if the space requires manned supervision. Ear protectors
should be provided for personnel required to enter such spaces.
9.2.13 Where two or more engines are employed,
the systems servicing them should be so designed that, as far as practicable,
failure of or explosion in one engine should not damage or impair
the functioning of the others.