title-14-part-25-sec25-851

303

Federal Aviation Administration, DOT

§ 25.851

than, the airport elevation by 2,000
feet, provided—

(1) In the event of probable failure

conditions of the cabin pressurization
system, the cabin pressure altitude
must not exceed 15,000 feet, or 2,000 feet
above the airport elevation, whichever
is higher; and

(2) The cabin pressurization system is

designed to minimize the time in flight
that occupants may be exposed to
cabin pressure altitudes exceeding 8,000
feet.

(d) When operating into or out of air-

ports with elevations at or above 8,000
feet, the cabin pressure high altitude
warning alert may be provided at up to
15,000 feet, or 2,000 feet above the air-
plane’s maximum takeoff and landing
altitude, whichever is greater, pro-
vided:

(1) During landing, the change in

cabin pressure high altitude warning
alert may not occur before the start of
descent into the high elevation airport
and, following takeoff, the cabin pres-
sure high altitude warning alert must
be reset to 10,000 feet before beginning
cruise operation;

(2) Indication is provided to the

flightcrew that the cabin pressure high
altitude warning alert has shifted
above 10,000 feet cabin pressure alti-
tude; and

(3) Either an alerting system is in-

stalled that notifies the flightcrew
members on flight deck duty when to
don oxygen in accordance with the ap-
plicable operating regulations, or a
limitation is provided in the airplane
flight manual that requires the pilot
flying the airplane to don oxygen when
the cabin pressure altitude warning has
shifted above 10,000 feet, and requires
other flightcrew members on flight
deck duty to monitor the cabin pres-
sure and utilize oxygen in accordance
with the applicable operating regula-
tions.

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25–38, 41 FR 55466, Dec. 20,
1976; Amdt. 25–87, 61 FR 28696, June 5, 1996;
Amdt. No. 25–151, 88 FR 39160, June 15, 2023;
88 FR 44032, July 11, 2023]

§ 25.843

Tests for pressurized cabins.

(a)

Strength test. The complete pres-

surized cabin, including doors, win-
dows, and valves, must be tested as a

pressure vessel for the pressure dif-
ferential specified in § 25.365(d).

(b)

Functional tests. The following

functional tests must be performed:

(1) Tests of the functioning and ca-

pacity of the positive and negative
pressure differential valves, and of the
emergency release valve, to stimulate
the effects of closed regulator valves.

(2) Tests of the pressurization system

to show proper functioning under each
possible condition of pressure, tem-
perature, and moisture, up to the max-
imum altitude for which certification
is requested.

(3) Flight tests, to show the perform-

ance of the pressure supply, pressure
and flow regulators, indicators, and
warning signals, in steady and stepped
climbs and descents at rates cor-
responding to the maximum attainable
within the operating limitations of the
airplane, up to the maximum altitude
for which certification is requested.

(4) Tests of each door and emergency

exit, to show that they operate prop-
erly after being subjected to the flight
tests prescribed in paragraph (b)(3) of
this section.

IRE

ROTECTION

§ 25.851

Fire extinguishers.

(a)

Hand fire extinguishers. (1) The fol-

lowing minimum number of hand fire
extinguishers must be conveniently lo-
cated and evenly distributed in pas-
senger compartments:

Passenger capacity

No. of extinguishers

7 through 30 ...............................

31 through 60 .............................

61 through 200 ...........................

201 through 300 ............................

301 through 400 ............................

401 through 500 ............................

501 through 600 ............................

601 through 700 ............................

(2) At least one hand fire extin-

guisher must be conveniently located
in the pilot compartment.

(3) At least one readily accessible

hand fire extinguisher must be avail-
able for use in each Class A or Class B
cargo or baggage compartment and in
each Class E or Class F cargo or bag-
gage compartment that is accessible to
crewmembers in flight.

(4) At least one hand fire extin-

guisher must be located in, or readily

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14 CFR Ch. I (1–1–24 Edition)

§ 25.853

accessible for use in, each galley lo-
cated above or below the passenger
compartment.

(5) Each hand fire extinguisher must

be approved.

(6) At least one of the required fire

extinguishers located in the passenger
compartment of an airplane with a pas-
senger capacity of at least 31 and not
more than 60, and at least two of the
fire extinguishers located in the pas-
senger compartment of an airplane
with a passenger capacity of 61 or more
must contain Halon 1211
(bromochlorodifluoromethane CBrC

), or equivalent, as the extinguishing

agent. The type of extinguishing agent
used in any other extinguisher required
by this section must be appropriate for
the kinds of fires likely to occur where
used.

(7) The quantity of extinguishing

agent used in each extinguisher re-
quired by this section must be appro-
priate for the kinds of fires likely to
occur where used.

(8) Each extinguisher intended for

use in a personnel compartment must
be designed to minimize the hazard of
toxic gas concentration.

(b) Built-in fire extinguishers. If a

built-in fire extinguisher is provided—

(1) Each built-in fire extinguishing

system must be installed so that—

(i) No extinguishing agent likely to

enter personnel compartments will be
hazardous to the occupants; and

(ii) No discharge of the extinguisher

can cause structural damage.

(2) The capacity of each required

built-in fire extinguishing system must
be adequate for any fire likely to occur
in the compartment where used, con-
sidering the volume of the compart-
ment and the ventilation rate. The ca-
pacity of each system is adequate if
there is sufficient quantity of agent to
extinguish the fire or suppress the fire
anywhere baggage or cargo is placed
within the cargo compartment for the
duration required to land and evacuate
the airplane.

[Amdt. 25–74, 56 FR 15456, Apr. 16, 1991, as
amended by Doc. No. Docket FAA–2014–0001,
Amdt. 25–142, 81 FR 7703, Feb. 16, 2016]

§ 25.853

Compartment interiors.

For each compartment occupied by

the crew or passengers, the following
apply:

(a) Materials (including finishes or

decorative surfaces applied to the ma-
terials) must meet the applicable test
criteria prescribed in part I of appendix
F of this part, or other approved equiv-
alent methods, regardless of the pas-
senger capacity of the airplane.

(b) [Reserved]
(c) In addition to meeting the re-

quirements of paragraph (a) of this sec-
tion, seat cushions, except those on
flight crewmember seats, must meet
the test requirements of part II of ap-
pendix F of this part, or other equiva-
lent methods, regardless of the pas-
senger capacity of the airplane.

(d) Except as provided in paragraph

(e) of this section, the following inte-
rior components of airplanes with pas-
senger capacities of 20 or more must
also meet the test requirements of
parts IV and V of appendix F of this
part, or other approved equivalent
method, in addition to the flamma-
bility requirements prescribed in para-
graph (a) of this section:

(1) Interior ceiling and wall panels,

other than lighting lenses and win-
dows;

(2) Partitions, other than transparent

panels needed to enhance cabin safety;

(3) Galley structure, including ex-

posed surfaces of stowed carts and
standard containers and the cavity
walls that are exposed when a full com-
plement of such carts or containers is
not carried; and

(4) Large cabinets and cabin stowage

compartments, other than underseat
stowage compartments for stowing
small items such as magazines and
maps.

(e) The interiors of compartments,

such as pilot compartments, galleys,
lavatories, crew rest quarters, cabinets
and stowage compartments, need not
meet the standards of paragraph (d) of
this section, provided the interiors of
such compartments are isolated from
the main passenger cabin by doors or
equivalent means that would normally
be closed during an emergency landing
condition.

(f) Smoking is not allowed in lava-

tories. If smoking is allowed in any