(a) There must be means to shut off or otherwise prevent hazardous
quantities of fuel, oil, de-icing fluid, and other flammable fluids from
flowing into, within, or through any designated fire zone, except that
this means need not be provided --
(1) For lines, fittings, and components forming an integral part of an
(2) For oil systems for turbine engine installations in which all
components of the system, including oil tanks, are fireproof or located in
areas not subject to engine fire conditions; or
(3) For engine oil systems in category B rotorcraft using reciprocating
engines of less than 500 cubic inches displacement.
(b) The closing of any fuel shutoff valve for any engine may not make
fuel unavailable to the remaining engines.
(c) For category A rotorcraft, no hazardous quantity of flammable fluid
may drain into any designated fire zone after shutoff has been
accomplished, nor may the closing of any fuel shutoff valve for an engine
make fuel unavailable to the remaining engines.
(d) The operation of any shutoff may not interfere with the later
emergency operation of any other equipment, such as the means for
declutching the engine from the rotor drive.
(e) Each shutoff valve and its control must be designed, located, and
protected to function properly under any condition likely to result from
fire in a designated fire zone.
(f) Except for ground-use-only auxiliary power unit installations,
there must be means to prevent inadvertent operation of each shutoff and
to make it possible to reopen it in flight after it has been closed.