137
Federal Aviation Administration, DOT
§ 121.337
period for at least 10 percent of the pas-
senger cabin occupants.
(2) When an airplane is operated at
flight altitudes up to and including
flight level 250 and cannot descend
safely to a flight altitude of 14,000 feet
within four minutes, or when an air-
plane is operated at flight altitudes
above flight level 250, oxygen must be
available at the rate prescribed by this
part for not less than 10 percent of the
passenger cabin occupants for the en-
tire flight after cabin depressurization,
at cabin pressure altitudes above 10,000
feet up to and including 14,000 feet and,
as applicable, to allow compliance with
§ 121.329(c) (2) and (3), except that there
must be not less than a 10-minute sup-
ply for the passenger cabin occupants.
(3) For first-aid treatment of occu-
pants who for physiological reasons
might require undiluted oxygen fol-
lowing descent from cabin pressure al-
titudes above flight level 250, a supply
of oxygen in accordance with the re-
quirements of § 25.1443(d) must be pro-
vided for two percent of the occupants
for the entire flight after cabin depres-
surization at cabin pressure altitudes
above 8,000 feet, but in no case to less
than one person. An appropriate num-
ber of acceptable dispensing units, but
in no case less than two, must be pro-
vided, with a means for the cabin at-
tendants to use this supply.
(f)
Passenger briefing.
Before flight is
conducted above flight level 250, a
crewmember shall instruct the pas-
sengers on the necessity of using oxy-
gen in the event of cabin depressuriza-
tion and shall point out to them the lo-
cation and demonstrate the use of the
oxygen-dispensing equipment.
[Doc. No. 6258, 29 FR 19205, Dec. 31, 1964, as
amended by Amdt. 121–11, 30 FR 12466, Sept.
30, 1965; Amdt. 121–132, 41 FR 55475, Dec. 20,
1976; Amdt. 121–262, 62 FR 13256, Mar. 19, 1997;
62 FR 15570, Apr. 1, 1997; Amdt. 121–306, 69 FR
62789, Oct. 27, 2004; Amdt. 121–383, 85 FR 16900,
Mar. 25, 2020]
§ 121.335 Equipment standards.
(a)
Reciprocating engine powered air-
planes.
The oxygen apparatus, the min-
imum rates of oxygen flow, and the
supply of oxygen necessary to comply
with § 121.327 must meet the standards
established in section 4b.651 of the Civil
Air Regulations as in effect on July 20,
1950, except that if the certificate hold-
er shows full compliance with those
standards to be impracticable, the Ad-
ministrator may authorize any change
in those standards that he finds will
provide an equivalent level of safety.
(b)
Turbine engine powered airplanes.
The oxygen apparatus, the minimum
rate of oxygen flow, and the supply of
oxygen necessary to comply with
§§ 121.329 and 121.333 must meet the
standards established in section 4b.651
of the Civil Air Regulations as in effect
on September 1, 1958, except that if the
certificate holder shows full compli-
ance with those standards to be im-
practicable, the Administrator may au-
thorize any changes in those standards
that he finds will provide an equivalent
level of safety.
§ 121.337 Protective breathing equip-
ment.
(a) The certificate holder shall fur-
nish approved protective breathing
equipment (PBE) meeting the equip-
ment, breathing gas, and communica-
tion requirements contained in para-
graph (b) of this section.
(b)
Pressurized and nonpressurized
cabin airplanes.
Except as provided in
paragraph (f) of this section, no person
may operate an airplane unless protec-
tive breathing equipment meeting the
requirements of this section is provided
as follows:
(1)
General.
The equipment must pro-
tect the flightcrew from the effects of
smoke, carbon dioxide or other harmful
gases or an oxygen deficient environ-
ment caused by other than an airplane
depressurization while on flight deck
duty and must protect crewmembers
from the above effects while combat-
ting fires on board the airplane.
(2) The equipment must be inspected
regularly in accordance with inspec-
tion guidelines and the inspection peri-
ods established by the equipment man-
ufacturer to ensure its condition for
continued serviceability and imme-
diate readiness to perform its intended
emergency purposes. The inspection pe-
riods may be changed upon a showing
by the certificate holder that the
changes would provide an equivalent
level of safety.
(3) That part of the equipment pro-
tecting the eyes must not impair the