131
Federal Aviation Administration, DOT
§ 121.321
handsets, headsets, microphones, selec-
tor switches, and signaling devices;
(b) Is approved in accordance with
§ 21.305 of this chapter;
(c) Is accessible for immediate use
from each of two flight crewmember
stations in the pilot compartment;
(d) For each required floor-level pas-
senger emergency exit which has an ad-
jacent flight attendant seat, has 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;
(e) Is capable of operation within 10
seconds by a flight attendant at each of
those stations in the passenger com-
partment from which its use is acces-
sible;
(f) Is audible at all passenger seats,
lavatories, and flight attendant seats
and work stations; and
(g) For transport category airplanes
manufactured on or after November 27,
1990, meets the requirements of § 25.1423
of this chapter.
[Doc. No. 24995, 54 FR 43926, Oct. 27, 1989]
§ 121.319 Crewmember interphone sys-
tem.
(a) No person may operate an air-
plane with a seating capacity of more
than 19 passengers unless the airplane
is equipped with a crewmember inter-
phone system that:
(1) [Reserved]
(2) Is capable of operation inde-
pendent of the public address system
required by § 121.318(a) except for
handsets, headsets, microphones, selec-
tor switches, and signaling devices; and
(3) Meets the requirements of para-
graph (b) of this section.
(b) The crewmember interphone sys-
tem required by paragraph (a) of this
section must be approved in accordance
with § 21.305 of this chapter and meet
the following requirements:
(1) It must provide a means of two-
way communication between the pilot
compartment and—
(i) Each passenger compartment; and
(ii) Each galley located on other than
the main passenger deck level.
(2) It must be accessible for imme-
diate use from each of two flight crew-
member stations in the pilot compart-
ment;
(3) It must be accessible for use from
at least one normal flight attendant
station in each passenger compart-
ment;
(4) It must be capable of operation
within 10 seconds by a flight attendant
at those stations in each passenger
compartment from which its use is ac-
cessible; and
(5) For large turbojet-powered air-
planes:
(i) It must be accessible for use at
enough flight attendant stations so
that all floor-level emergency exits (or
entryways to those exits in the case of
exits located within galleys) in each
passenger compartment are observable
from one or more of those stations so
equipped;
(ii) It must have an alerting system
incorporating aural or visual signals
for use by flight crewmembers to alert
flight attendants and for use by flight
attendants to alert flight crew-
members;
(iii) The alerting system required by
paragraph (b)(5)(ii) of this section must
have a means for the recipient of a call
to determine whether it is a normal
call or an emergency call; and
(iv) When the airplane is on the
ground, it must provide a means of
two-way communication between
ground personnel and either of at least
two flight crewmembers in the pilot
compartment. The interphone system
station for use by ground personnel
must be so located that personnel
using the system may avoid visible de-
tection from within the airplane.
[Doc. No. 10865, 38 FR 21494, Aug. 9, 1973, as
amended by Amdt. 121–121, 40 FR 42186, Sept.
11, 1975; Amdt. 121–149, 43 FR 50602, Oct. 30,
1978; Amdt. 121–178, 47 FR 13316, Mar. 29, 1982;
Amdt. 121–253, 61 FR 2611, Jan. 26, 1996]
§ 121.321 Operations in icing.
After October 21, 2013, no person may
operate an airplane with a certificated
maximum takeoff weight less than
60,000 pounds in conditions conducive
to airframe icing unless it complies
with this section. As used in this sec-
tion, the phrase ‘‘conditions conducive
to airframe icing’’ means visible mois-
ture at or below a static air tempera-
ture of 5
°
C or a total air temperature
