Sec. 25.1423 - Public address system.
A public address system required by this
chapter must --
(a) Be powerable when the aircraft is in
flight or stopped on the ground, after the shutdown or failure of all
engines and auxiliary power units, or the disconnection or failure of all
power sources dependent on their continued operation, for --
(1) A time duration of at least 10
minutes, including an aggregate time duration of at least 5 minutes of
announcements made by flight and cabin crewmembers, considering all other
loads which may remain powered by the same source when all other power
sources are inoperative; and
(2) An additional time duration in its
standby state appropriate or required for any other loads that are powered
by the same source and that are essential to safety of flight or required
during emergency conditions.
(b) Be capable of operation within 10
seconds by a flight attendant at those stations in the passenger
compartment from which the system is accessible.
(c) Be intelligible at all passenger
seats, lavatories, and flight attendant seats and work stations.
(d) Be designed so that no unused,
unstowed microphone will render the system inoperative.
(e) Be capable of functioning
independently of any required crewmember interphone system.
(f) Be accessible for immediate use from
each of two flight crewmember stations in the pilot compartment.
(g) For each required floor-level
passenger emergency exit which has an adjacent flight attendant seat, have
a microphone which is readily accessible to the seated flight attendant,
except that one microphone may serve more than one exit, provided the
proximity of the exits allows unassisted verbal communication between
seated flight attendants.
[Doc. No. 26003, 58 FR 45229, Aug. 26, 1993]