135
Federal Aviation Administration, DOT
§ 121.333
(2) For flights at cabin pressure alti-
tudes above 14,000 feet, up to and in-
cluding 15,000 feet, enough oxygen for
that part of the flight at those alti-
tudes for 30 percent of the passengers.
(3) For flights at cabin pressure alti-
tudes above 15,000 feet, enough oxygen
for each passenger carried during the
entire flight at those altitudes.
§ 121.331 Supplemental oxygen re-
quirements for pressurized cabin
airplanes: Reciprocating engine
powered airplanes.
(a) When operating a reciprocating
engine powered airplane pressurized
cabin, each certificate holder shall
equip the airplane to comply with
paragraphs (b) through (d) of this sec-
tion in the event of cabin pressuriza-
tion failure.
(b)
For crewmembers.
When operating
at flight altitudes above 10,000 feet, the
certificate holder shall provide enough
oxygen for each crewmember for the
entire flight at those altitudes and not
less than a two-hour supply for each
flight crewmember on flight deck duty.
The required two hours supply is that
quantity of oxygen necessary for a con-
stant rate of descent from the air-
plane’s maximum certificated oper-
ating altitude to 10,000 feet in ten min-
utes and followed by 110 minutes at
10,000 feet. The oxygen required by
§ 121.337 may be considered in deter-
mining the supplemental breathing
supply required for flight crewmembers
on flight deck duty in the event of
cabin pressurization failure.
(c)
For passengers.
When operating at
flight altitudes above 8,000 feet, the
certificate holder shall provide oxygen
as follows:
(1) When an airplane is not flown at
a flight altitude above flight level 250,
enough oxygen for 30 minutes for 10
percent of the passengers, if at any
point along the route to be flown the
airplane can safely descend to a flight
altitude of 14,000 feet or less within
four minutes.
(2) If the airplane cannot descend to
a flight altitude of 14,000 feet or less
within four minutes, the following sup-
ply of oxygen must be provided:
(i) For that part of the flight that is
more than four minutes duration at
flight altitudes above 15,000 feet, the
supply required by § 121.327(c)(3).
(ii) For that part of the flight at
flight altitudes above 14,000 feet, up to
and including 15,000 feet, the supply re-
quired by § 121.327(c)(2).
(iii) For flight at flight altitudes
above 8,000 feet up to and including
14,000 feet, enough oxygen for 30 min-
utes for 10 percent of the passengers.
(3) When an airplane is flown at a
flight altitude above flight level 250,
enough oxygen for 30 minutes for 10
percent of the passengers for the entire
flight (including emergency descent)
above 8,000 feet, up to and including
14,000 feet, and to comply with
§ 121.327(c) (2) and (3) for flight above
14,000 feet.
(d) For the purposes of this section it
is assumed that the cabin pressuriza-
tion failure occurs at a time during
flight that is critical from the stand-
point of oxygen need and that after the
failure the airplane will descend, with-
out exceeding its normal operating
limitations, to flight altitudes allow-
ing safe flight with respect to terrain
clearance.
[Doc. No. 6258, 29 FR 19205, Dec. 31, 1964, as
amended by Amdt. 121–132, 41 FR 55475, Dec.
20, 1976]
§ 121.333 Supplemental oxygen for
emergency descent and for first aid;
turbine engine powered airplanes
with pressurized cabins.
(a)
General.
When operating a turbine
engine powered airplane with a pres-
surized cabin, the certificate holder
shall furnish oxygen and dispensing
equipment to comply with paragraphs
(b) through (e) of this section in the
event of cabin pressurization failure.
(b)
Crewmembers.
When operating at
flight altitudes above 10,000 feet, the
certificate holder shall supply enough
oxygen to comply with § 121.329, but not
less than a two-hour supply for each
flight crewmember on flight deck duty.
The required two hours supply is that
quantity of oxygen necessary for a con-
stant rate of descent from the air-
plane’s maximum certificated oper-
ating altitude to 10,000 feet in ten min-
utes and followed by 110 minutes at
10,000 feet. The oxygen required in the
event of cabin pressurization failure by
136
14 CFR Ch. I (1–1–24 Edition)
§ 121.333
§ 121.337 may be included in deter-
mining the supply required for flight
crewmembers on flight deck duty.
(c)
Use of oxygen masks by flight crew-
members.
(1) When operating at flight
altitudes above flight level 250, each
flight crewmember on flight deck duty
must be provided with an oxygen mask
so designed that it can be rapidly
placed on his face from its ready posi-
tion, properly secured, sealed, and sup-
plying oxygen upon demand; and so de-
signed that after being placed on the
face it does not prevent immediate
communication between the flight
crewmember and other crewmembers
over the airplane intercommunication
system. When it is not being used at
flight altitudes above flight level 250,
the oxygen mask must be kept in con-
dition for ready use and located so as
to be within the immediate reach of
the flight crewmember while at his
duty station.
(2) When operating at flight altitudes
above flight level 250, one pilot at the
controls of the airplane shall at all
times wear and use an oxygen mask se-
cured, sealed, and supplying oxygen, in
accordance with the following:
(i) The one pilot need not wear and
use an oxygen mask at or below the
following flight levels if each flight
crewmember on flight deck duty has a
quick-donning type of oxygen mask
that the certificate holder has shown
can be placed on the face from its
ready position, properly secured,
sealed, and supplying oxygen upon de-
mand, with one hand and within five
seconds:
(A) For airplanes having a passenger
seat configuration of more than 30
seats, excluding any required crew-
member seat, or a payload capacity of
more than 7,500 pounds, at or below
flight level 410.
(B) For airplanes having a passenger
seat configuration of less than 31 seats,
excluding any required crewmember
seat, and a payload capacity of 7,500
pounds or less, at or below flight level
350.
(ii) Whenever a quick-donning type of
oxygen mask is to be used under this
section, the certificate holder shall
also show that the mask can be put on
without disturbing eye glasses and
without delaying the flight crew-
member from proceeding with his as-
signed emergency duties. The oxygen
mask after being put on must not pre-
vent immediate communication be-
tween the flight crewmember and other
crewmembers over the airplane inter-
communication system.
(3) Notwithstanding paragraph (c)(2)
of this section, if for any reason at any
time it is necessary for one pilot to
leave his station at the controls of the
airplane when operating at flight alti-
tudes above flight level 410, the re-
maining pilot at the controls shall put
on and use his oxygen mask until the
other pilot has returned to his duty
station.
(4) Before the takeoff of a flight, each
flight crewmember shall personally
preflight his oxygen equipment to in-
sure that the oxygen mask is func-
tioning, fitted properly, and connected
to appropriate supply terminals, and
that the oxygen supply and pressure
are adequate for use.
(d)
Use of portable oxygen equipment by
cabin attendants.
After November 28,
2005 each mask used for portable oxy-
gen equipment must be connected to
its oxygen supply. Above flight level
250, one of the following is required:
(1) Each attendant shall carry port-
able oxygen equipment with a 15
minute supply of oxygen; or
(2) There must be sufficient portable
oxygen equipment (including masks
and spare outlets) distributed through-
out the cabin so that such equipment is
immediately available to each attend-
ant, regardless of their location in the
cabin; or
(3) There are sufficient spare outlets
and masks distributed throughout the
cabin to ensure immediate availability
of oxygen to each cabin attendant, re-
gardless of their location in the cabin.
(e)
Passenger cabin occupants.
When
the airplane is operating at flight alti-
tudes above 10,000 feet, the following
supply of oxygen must be provided for
the use of passenger cabin occupants:
(1) When an airplane certificated to
operate at flight altitudes up to and in-
cluding flight level 250, can at any
point along the route to be flown, de-
scend safely to a flight altitude of
14,000 feet or less within four minutes,
oxygen must be available at the rate
prescribed by this part for a 30-minute
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