(a) Each battery ignition system must be supplemented with a generator
that is automatically available as an alternate source of electrical
energy to allow continued engine operation if any battery becomes
(b) The capacity of batteries and generators must be large enough to
meet the simultaneous demands of the engine ignition system and the
greatest demands of any electrical system components that draw from the
(c) The design of the engine ignition system must account for --
(1) The condition of an inoperative generator;
(2) The condition of a completely depleted battery with the generator
running at its normal operating speed; and
(3) The condition of a completely depleted battery with the generator
operating at idling speed, if there is only one battery.
(d) Magneto ground wiring (for separate ignition circuits) that lies on
the engine side of any firewall must be installed, located, or protected,
to minimize the probability of the simultaneous failure of two or more
wires as a result of mechanical damage, electrical fault, or other cause.
(e) No ground wire for any engine may be routed through a fire zone of
another engine unless each part of that wire within that zone is
(f) Each ignition system must be independent of any electrical circuit
that is not used for assisting, controlling, or analyzing the operation of
(g) There must be means to warn appropriate crewmembers if the
malfunctioning of any part of the electrical system is causing the
continuous discharge of any battery necessary for engine ignition.