133 

Federal Aviation Administration, DOT 

§ 121.327 

those required by §§ 121.305 through 
121.321 and 121.803: 

(a) Position lights. 
(b) An anti-collision light. 
(c) Two landing lights, except that 

only one landing light is required for 
nontransport category airplanes type 
certificated after December 31, 1964. 

(d) Instrument lights providing 

enough light to make each required in-
strument, switch, or similar instru-
ment, easily readable and installed so 
that the direct rays are shielded from 
the flight crewmembers’ eyes and that 
no objectionable reflections are visible 
to them. There must be a means of con-
trolling the intensity of illumination 
unless it is shown that nondimming in-
strument lights are satisfactory. 

(e) An airspeed-indicating system 

with heated pitot tube or equivalent 
means for preventing malfunctioning 
due to icing. 

(f) A sensitive altimeter. 

[Doc. No. 6258, 29 FR 19205, Dec. 31, 1964, as 
amended by Amdt. 121–251, 60 FR 65932, Dec. 
20, 1995; Amdt. 121–281, 66 FR 19043, Apr. 12, 
2001] 

§ 121.325 Instruments and equipment 

for operations under IFR or over- 

the-top. 

No person may operate an airplane 

under IFR or over-the-top conditions 
under this part unless it is equipped 
with the following instruments and 
equipment, in addition to those re-
quired by §§ 121.305 through 121.321 and 
121.803: 

(a) An airspeed indicating system 

with heated pitot tube or equivalent 
means for preventing malfunctioning 
due to icing. 

(b) A sensitive altimeter. 
(c) Instrument lights providing 

enough light to make each required in-
strument, switch, or similar instru-
ment, easily readable and so installed 
that the direct rays are shielded from 
the flight crewmembers’ eyes and that 
no objectionable reflections are visible 
to them, and a means of controlling 
the intensity of illumination unless it 
is shown that nondimming instrument 
lights are satisfactory. 

[Doc. No. 6258, 29 FR 19205, Dec. 31, 1964, as 
amended at Amdt. 121–281, 66 FR 19043, Apr. 
12, 2001] 

§ 121.327 Supplemental oxygen: Recip-

rocating engine powered airplanes. 

(a) 

General. 

Except where supple-

mental oxygen is provided in accord-
ance with § 121.331, no person may oper-
ate an airplane unless supplemental ox-
ygen is furnished and used as set forth 
in paragraphs (b) and (c) of this sec-
tion. The amount of supplemental oxy-
gen required for a particular operation 
is determined on the basis of flight al-
titudes and flight duration, consistent 
with the operation procedures estab-
lished for each operation and route. 

(b) 

Crewmembers. 

(1) At cabin pressure 

altitudes above 10,000 feet up to and in-
cluding 12,000 feet, oxygen must be pro-
vided for, and used by, each member of 
the flight crew on flight deck duty, and 
must be provided for other crew-
members, for that part of the flight at 
those altitudes that is of more than 30 
minutes duration. 

(2) At cabin pressure altitudes above 

12,000 feet, oxygen must be provided 
for, and used by, each member of the 
flight crew on flight deck duty, and 
must be provided for other crew-
members, during the entire flight time 
at those altitudes. 

(3) When a flight crewmember is re-

quired to use oxygen, he must use it 
continuously, except when necessary to 
remove the oxygen mask or other dis-
penser in connection with his regular 
duties. Standby crewmembers who are 
on call or are definitely going to have 
flight deck duty before completing the 
flight must be provided with an 
amount of supplemental oxygen equal 
to that provided for crewmembers on 
duty other than on flight deck duty. If 
a standby crewmember is not on call 
and will not be on flight deck duty dur-
ing the remainder of the flight, he is 
considered to be a passenger for the 
purposes of supplemental oxygen re-
quirements. 

(c) 

Passengers. 

Each certificate holder 

shall provide a supply of oxygen, ap-
proved for passenger safety, in accord-
ance with the following: 

(1) For flights of more than 30 min-

utes duration at cabin pressure alti-
tudes above 8,000 feet up to and includ-
ing 14,000 feet, enough oxygen for 30 
minutes for 10 percent of the pas-
sengers. 

134 

14 CFR Ch. I (1–1–24 Edition) 

§ 121.329 

(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. 

(d) For the purposes of this subpart 

cabin pressure altitude 

means the pres-

sure altitude corresponding with the 
pressure in the cabin of the airplane, 
and 

flight altitude 

means the altitude 

above sea level at which the airplane is 
operated. For airplanes without pres-
surized cabins, ‘‘cabin pressure alti-
tude’’ and ‘‘flight altitude’’ mean the 
same thing. 

§ 121.329 Supplemental oxygen for sus-

tenance: Turbine engine powered 

airplanes. 

(a) 

General. 

When operating a turbine 

engine powered airplane, each certifi-
cate holder shall equip the airplane 
with sustaining oxygen and dispensing 
equipment for use as set forth in this 
section: 

(1) The amount of oxygen provided 

must be at least the quantity nec-
essary to comply with paragraphs (b) 
and (c) of this section. 

(2) The amount of sustaining and 

first-aid oxygen required for a par-
ticular operation to comply with the 
rules in this part is determined on the 
basis of cabin pressure altitudes and 
flight duration, consistent with the op-
erating procedures established for each 
operation and route. 

(3) The requirements for airplanes 

with pressurized cabins are determined 
on the basis of cabin pressure altitude 
and the assumption that a cabin pres-
surization failure will occur at the alti-
tude or point of flight that is most 
critical from the standpoint of oxygen 
need, and that after the failure the air-
plane will descend in accordance with 
the emergency procedures specified in 
the Airplane Flight Manual, without 
exceeding its operating limitations, to 
a flight altitude that will allow suc-
cessful termination of the flight. 

(4) Following the failure, the cabin 

pressure altitude is considered to be 
the same as the flight altitude unless it 
is shown that no probable failure of the 

cabin or pressurization equipment will 
result in a cabin pressure altitude 
equal to the flight altitude. Under 
those circumstances, the maximum 
cabin pressure altitude attained may 
be used as a basis for certification or 
determination of oxygen supply, or 
both. 

(b) 

Crewmembers. 

Each certificate 

holder shall provide a supply of oxygen 
for crewmembers in accordance with 
the following: 

(1) At cabin pressure altitudes above 

10,000 feet, up to and including 12,000 
feet, oxygen must be provided for and 
used by each member of the flight crew 
on flight deck duty and must be pro-
vided for other crewmembers for that 
part of the flight at those altitudes 
that is of more than 30 minutes dura-
tion. 

(2) At cabin pressure altitudes above 

12,000 feet, oxygen must be provided 
for, and used by, each member of the 
flight crew on flight deck duty, and 
must be provided for other crew-
members during the entire flight at 
those altitudes. 

(3) When a flight crewmember is re-

quired to use oxygen, he must use it 
continuously except when necessary to 
remove the oxygen mask or other dis-
penser in connection with his regular 
duties. Standby crewmembers who are 
on call or are definitely going to have 
flight deck duty before completing the 
flight must be provided with an 
amount of supplemental oxygen equal 
to that provided for crewmembers on 
duty other than on flight duty. If a 
standby crewmember is not on call and 
will not be on flight deck duty during 
the remainder of the flight, he is con-
sidered to be a passenger for the pur-
poses of supplemental oxygen require-
ments. 

(c) 

Passengers. 

Each certificate holder 

shall provide a supply of oxygen for 
passengers in accordance with the fol-
lowing: 

(1) For flights at cabin pressure alti-

tudes above 10,000 feet, up to and in-
cluding 14,000 feet, enough oxygen for 
that part of the flight at those alti-
tudes that is of more than 30 minutes 
duration, for 10 percent of the pas-
sengers.