Sec. 23.953 - Fuel system independence.
(a) Each fuel system for a multiengine
airplane must be arranged so that, in at least one system configuration,
the failure of any one component (other than a fuel tank) will not result
in the loss of power of more than one engine or require immediate action
by the pilot to prevent the loss of power of more than one engine.
(b) If a single fuel tank (or series of
fuel tanks interconnected to function as a single fuel tank) is used on a
multiengine airplane, the following must be provided:
(1) Independent tank outlets for each
engine, each incorporating a shut-off valve at the tank. This shutoff
valve may also serve as the fire wall shutoff valve required if the line
between the valve and the engine compartment does not contain more than
one quart of fuel (or any greater amount shown to be safe) that can escape
into the engine compartment.
(2) At least two vents arranged to
minimize the probability of both vents becoming obstructed simultaneously.
(3) Filler caps designed to minimize the
probability of incorrect installation or inflight loss.
(4) A fuel system in which those parts
of the system from each tank outlet to any engine are independent of each
part of the system supplying fuel to any other engine.
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as
amended by Amdt. 23-7, 34 FR 13093 Aug. 13, 1969; Amdt. 23-43, 58 FR
18971, Apr. 9, 1993]