Federal Register / Vol. 89, No. 240 / Friday, December 13, 2024 / Rules and Regulations 100723 

TABLE 3 TO PARAGRAPH 4.1.1.—RELATIVE HUMIDITY AS A FUNCTION OF DRY-BULB AND WET-BULB TEMPERATURES FOR

WHOLE-HOME DEHUMIDIFIERS

Wet-bulb temperature 

(°F) 

Dry-bulb temperature (°F) 

72.5 72.6 72.7 72.8 72.9 73 73.1 73.2 73.3 73.4 73.5 

63.3 .................................................. 60.59 60.26 59.92 59.59 59.26 58.92 58.6 58.27 57.94 57.62 57.3 

63.4 .................................................. 60.98 60.64 60.31 59.75 59.64 59.31 58.98 58.65 58.32 58 57.67 

63.5 .................................................. 61.37 61.03 60.7 60.36 60.02 59.69 59.36 59.03 58.7 58.38 58.05 

63.6 .................................................. 61.76 61.42 61.08 60.75 60.41 60.08 59.74 59.41 59.08 58.76 58.43 

63.7 .................................................. 62.16 61.81 61.47 61.13 60.8 60.46 60.13 59.8 59.47 59.14 58.81 

63.8 .................................................. 62.55 62.2 61.86 61.52 61.18 60.85 60.51 60.18 59.85 59.52 59.19 

63.9 .................................................. 62.94 62.6 62.25 61.91 61.57 61.23 60.9 60.56 60.23 59.9 59.57 

* * * * * 

[FR Doc. 2024–29566 Filed 12–12–24; 8:45 am] 

BILLING CODE 0099–10–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. FAA–2024–1310; Special 

Conditions No. 25–873–SC] 

Special Conditions: Aerocon 

Engineering Company, Airbus Model 

A350–941 Airplane; Forward Lower 

Lobe Crew Rest Compartment 

Installation 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions. 

SUMMARY: These special conditions are 

issued for the Airbus Model A350–941 

airplane. This airplane, as modified by 

Aerocon Engineering Company 

(Aerocon), will have a novel or unusual 

design feature when compared to the 

state of technology envisioned in the 

airworthiness standards for transport 

category airplanes. This design feature 

is an installation of a lower lobe crew 

rest (LLCR) compartment located under 

the passenger cabin floor in the cargo 

compartment. The applicable 

airworthiness regulations do not contain 

adequate or appropriate safety standards 

for this design feature. These special 

conditions contain the additional safety 

standards that the Administrator 

considers necessary to establish a level 

of safety equivalent to that established 

by the existing airworthiness standards. 

DATES: Effective December 13, 2024. 

FOR FURTHER INFORMATION CONTACT: 

Daniel Jacquet, Cabin Safety, AIR–624, 

Technical Policy Branch, Policy and 

Standards Division, Aircraft 

Certification Service, Federal Aviation 

Administration, 2200 South 216th 

Street, Des Moines, Washington 98198; 

telephone and fax (206) 231–3208; email 

daniel.jacquet@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

On August 27, 2021, Aerocon applied 

for a supplemental type certificate for a 

LLCR installation in the Model A350– 

941 airplane. The Airbus Model A350– 

941 airplane is a twin-engine, transportcategory airplane with a maximum 

takeoff weight of 623,908 pounds and 

maximum seating for 480 passengers. 

Type Certification Basis 

Under the provisions of 14 CFR 

21.101, Aerocon must show that the 

Airbus Model A350–941 airplane, as 

changed, continues to meet the 

applicable provisions of the regulations 

listed in Type Certificate No. T000631B 

or the applicable regulations in effect on 

the date of application for the change, 

except for earlier amendments as agreed 

upon by the FAA. 

If the Administrator finds that the 

applicable airworthiness regulations 

(e.g., 14 CFR part 25) do not contain 

adequate or appropriate safety standards 

for the Airbus A350–941 airplane 

because of a novel or unusual design 

feature, special conditions are 

prescribed under the provisions of 

§ 21.16. 

Special conditions are initially 

applicable to the model for which they 

are issued. Should the applicant apply 

for a supplemental type certificate to 

modify any other model included on the 

same type certificate to incorporate the 

same novel or unusual design feature, 

these special conditions would also 

apply to the other model under § 21.101. 

In addition to the applicable 

airworthiness regulations and special 

conditions, the Airbus A350–941 series 

airplane must comply with the exhaustemission requirements of 14 CFR part 

34, and the noise-certification 

requirements of 14 CFR part 36. 

The FAA issues special conditions, as 

defined in 14 CFR 11.19, in accordance 

with § 11.38, and they become part of 

the type certification basis under 

§ 21.101. 

Novel or Unusual Design Features 

The Airbus A350–941 airplane will 

incorporate the following novel or 

unusual design feature: 

The installation of a LLCR under the 

passenger cabin floor in the cargo 

compartment. 

Discussion 

Section 25.819 applies to lower deck 

service compartments (including 

galleys) but is not directly applicable to 

forward LLCR compartments. The 

applicable airworthiness regulations do 

not contain adequate or appropriate 

safety standards for this design feature. 

Special conditions are required for the 

certification of the LLCR to supplement 

part 25. 

The LLCR will be located under the 

passenger cabin floor in the forward 

cargo compartment of Airbus A350–941 

model airplanes. It will be the size of 

three standard airfreight containers and 

be removeable from the cargo 

compartment. Occupancy of the LLCR 

will be limited to a maximum of eight 

crew members, and it will only be 

occupied in flight, i.e., not during taxi, 

takeoff or landing. A smoke detection 

system, fire extinguishing system, 

oxygen system and occupant amenities 

will be provided. 

The LLCR will be accessed from the 

main deck via a stair house. The floor 

within the stair house has an access 

hatch that leads to the stairs, which 

occupants use to descend into the LLCR. 

This hatch locks automatically in the 

open position when fully opened. In 

addition, there will be an emergency 

hatch, which opens directly into the 

main passenger cabin area. 

The LLCR also has a maintenance 

access/ground loading door, which 

allows access to and from the cargo 

compartment. The intended use of this 

door is to allow cargo loading and 

maintenance personnel to enter the 

LLCR from the cargo compartment when 


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the airplane is on the ground and not 

moving. 

The special conditions contain the 

additional safety standards that the 

Administrator considers necessary to 

establish a level of safety equivalent to 

that established by the existing 

airworthiness standards. 

Discussion of Comments 

The FAA issued Notice of Proposed 

Special Conditions No. 25–24–04–SC 

for Airbus Model A350–941 airplanes, 

which was published in the Federal 

Register on September 11, 2024 (89 FR 

73604). 

The FAA received a response from 

Airbus Commercial Aircraft (Airbus) 

requesting the FAA consider Special 

Conditions No. 25–281–SC as the 

minimum set of requirements for the 

design of the A350–941 lower deck crew 

rest compartment. Airbus request the 

FAA issue special conditions consistent 

with previously approved special 

conditions for similar installations. 

The FAA agrees with the Airbus 

response. The limitations and 

conditions of this special condition are 

essentially the same as the limitations 

and conditions listed in special 

condition number 25–281–SC. 

The special conditions are adopted as 

proposed. 

Applicability 

As discussed above, these special 

conditions are applicable to Airbus 

Model A350–941 airplanes as modified 

by Aerocon. Should the applicant apply 

for a supplemental type certificate to 

modify any other model included on the 

same type certificate to incorporate the 

same novel or unusual design feature, 

these special conditions would apply to 

the other model as well. 

Under standard practice, the effective 

date of final special conditions would 

be 30 days after the date of publication 

in the Federal Register. However, as the 

certification date for the Airbus Model 

A350–941 is imminent, the FAA finds 

that good cause exists to make these 

special conditions effective upon 

publication. 

Conclusion 

This action affects only certain novel 

or unusual design feature on the Airbus 

350–941 airplane. It is not a rule of 

general applicability and affects only 

the applicant who applied to the FAA 

for approval of these features on the 

airplane. 

List of Subjects in 14 CFR Part 25 

Aircraft, Aviation safety, Reporting 

and recordkeeping requirements. 

Authority Citation 

The authority citation for these 

special conditions is as follows: 

Authority: 49 U.S.C. 106(f), 106(g), 40113, 

44701, 44702, 44704. 

The Special Conditions 

Accordingly, pursuant to the 

authority delegated to me by the 

Administrator, the following special 

conditions are issued as part of the type 

certification basis for Airbus Model 

A350–941 airplanes, as modified by 

Aerocon Engineering Company. The 

LLCR must meet the below 

requirements: 

1. Occupancy of the forward lower 

lobe crew rest compartment is limited to 

a maximum of eight. There must be an 

approved seat or berth able to withstand 

the maximum flight loads when 

occupied for each occupant permitted in 

the crew rest compartment. 

(a) There must be appropriate 

placards displayed in a conspicuous 

place at each entrance to the LLCR 

compartment to indicate: 

(1) The maximum number of 

occupants allowed; 

(2) That occupancy is restricted to 

crewmembers trained in the evacuation 

procedures for the crew rest 

compartment; 

(3) That occupancy is prohibited 

during taxi, take-off and landing; 

(4) That smoking is prohibited in the 

crew rest compartment; 

(5) That hazardous quantities of 

flammable fluids, explosives, or other 

dangerous cargo is prohibited from the 

crew rest compartment. 

(6) That the crew rest area must be 

limited to the stowage of crew personal 

luggage and must not be used for the 

stowage of cargo or passenger baggage. 

(b) There must be at least one ashtray 

located conspicuously on or near the 

entry side of any entrance, usable inflight, to the crew rest compartment. 

(c) There must be a means to prevent 

passengers from entering the 

compartment in the event of an 

emergency or when no flight attendant 

is present. 

(d) There must be a means for any 

door installed between the crew rest 

compartment and passenger cabin to be 

capable of being quickly opened from 

inside the compartment, even when 

crowding occurs at each side of the 

door. 

(e) For all doors installed in the 

evacuation routes, there must be a 

means to preclude anyone from being 

trapped inside the compartment. If a 

locking mechanism is installed, it must 

be capable of being unlocked from the 

outside without special tools. The lock 

must not prevent opening from the 

inside of the compartment at any time. 

2. There must be at least two 

emergency evacuation routes, which 

could be used by each occupant of the 

crew rest compartment to rapidly 

evacuate to the main cabin and be able 

to be closed from the main passenger 

cabin after evacuation. In addition— 

(a) The routes must be located with 

one at each end of the compartment, or 

with two having sufficient separation 

within the compartment and between 

the routes to minimize the possibility of 

an event (either inside or outside of the 

crew rest compartment) rendering both 

routes inoperative. 

(b) The routes must be designed to 

minimize the possibility of blockage, 

which might result from fire, 

mechanical or structural failure, or 

persons standing on top of or against the 

escape route. If an evacuation route 

utilizes an area where normal 

movement of passengers occurs, it must 

be demonstrated that passengers would 

not impede egress to the main deck. If 

a hatch is installed in an evacuation 

route, the point at which the evacuation 

route terminates in the passenger cabin 

should not be located where normal 

movement by passengers or crew occurs 

(main aisle, cross aisle, passageway or 

galley complex). If such a location 

cannot be avoided, special 

consideration must be taken to ensure 

that the hatch or door can be opened 

when a person, the weight of a ninetyfifth percentile male, is standing on the 

hatch or door. The use of evacuation 

routes must not be dependent on any 

powered device. If there is low 

headroom at or near an evacuation 

route, provisions must be made to 

prevent or to protect occupants of the 

crew rest area from head injury. 

(c) Emergency evacuation procedures, 

including the emergency evacuation of 

an incapacitated occupant from the 

crew rest compartment, must be 

established. All of these procedures 

must be transmitted to the operator for 

incorporation into their training 

programs and appropriate operational 

manuals. 

(d) There must be a limitation in the 

airplane flight manual or other suitable 

means requiring that crewmembers be 

trained in the use of evacuation routes. 

3. There must be a means for the 

evacuation of an incapacitated person 

(representative of a 95th percentile 

male) from the crew rest compartment 

to the passenger cabin floor. The 

evacuation must be demonstrated for all 

evacuation routes. A flight attendant or 

other crewmember (a total of one 

assistant within the crew rest area) may 

provide assistance in the evacuation. 


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Additional assistance may be provided 

by up to three persons in the main 

passenger compartment. For evacuation 

routes having stairways, the additional 

assistants may descend down to one 

half the elevation change from the main 

deck to the lower deck compartment, or 

to the first landing, whichever is higher. 

4. The following signs and placards 

must be provided in the crew rest 

compartment: 

(a) At least one exit sign, located near 

each exit, meeting the requirements of 

§ 25.812(b)(1)(i) at Amendment 25–58, 

except that a sign with reduced 

background area of no less than 5.3 

square inches (excluding the letters) 

may be utilized, provided that it is 

installed such that the material 

surrounding the exit sign is light in 

color (e.g., white, cream, light beige). If 

the material surrounding the exit sign is 

not light in color, a sign with a 

minimum of a one-inch wide 

background border around the letters 

would also be acceptable; 

(b) An appropriate placard located 

near each exit defining the location and 

the operating instructions for each 

evacuation route; 

(c) Placards must be readable from a 

distance of 30 inches under emergency 

lighting conditions; and 

(d) The exit handles and evacuation 

path operating instruction placards 

must be illuminated to at least 160 

microlamberts under emergency lighting 

conditions. 

5. In the event of failure of the 

aircraft’s main power system, or of the 

normal crew rest compartment lighting 

system, there must be a means for 

emergency illumination to be 

automatically provided for the crew rest 

compartment. 

(a) This emergency illumination must 

be independent of the main lighting 

system. 

(b) The sources of general cabin 

illumination may be common to both 

the emergency and the main lighting 

systems if the power supply to the 

emergency lighting system is 

independent of the power supply to the 

main lighting system. 

(c) The illumination level must be 

sufficient for the occupants of the crew 

rest compartment to locate and transfer 

to the main passenger cabin floor by 

means of each evacuation route. 

(d) The illumination level must be 

sufficient with the privacy curtains in 

the closed position for each occupant of 

the crew rest to locate a deployed 

oxygen mask. 

6. There must be means for two-way 

voice communications between 

crewmembers on the flight deck and 

occupants of the crew rest compartment. 

There must also be public address (PA) 

system microphones at each flight 

attendant seat required to be near a floor 

level exit in the passenger cabin per 

§ 25.785(h) at Amendment 25–51. The 

PA system must allow two-way voice 

communications between flight 

attendants and the occupants of the 

crew rest compartment, except that one 

microphone may serve more than one 

exit provided the proximity of the exits 

allows unassisted verbal 

communication between seated flight 

attendants. 

7. There must be a means for manual 

activation of an aural emergency alarm 

system, audible during normal and 

emergency conditions, to enable 

crewmembers on the flight deck and at 

each pair of required floor level 

emergency exits to alert occupants of 

the crew rest compartment of an 

emergency situation. Use of a public 

address or crew interphone system will 

be acceptable, provided an adequate 

means of differentiating between normal 

and emergency communications is 

incorporated. The system must be 

powered in flight, after the shutdown or 

failure of all engines and auxiliary 

power units (APU), or the disconnection 

or failure of all power sources 

dependent on their continued operation 

(i.e., engine & APU), for a period of at 

least ten minutes. 

8. There must be a means, readily 

detectable by seated or standing 

occupants of the crew rest compartment, 

which indicates when seat belts should 

be fastened. In the event there are no 

seats, at least one means must be 

provided to cover anticipated 

turbulence (e.g., sufficient handholds). 

Seat belt type restraints must be 

provided for berths and must be 

compatible for the sleeping attitude 

during cruise conditions. There must be 

a placard on each berth requiring that 

seat belts must be fastened when 

occupied. If compliance with any of the 

other requirements of these special 

conditions is predicated on specific 

head location, there must be a placard 

identifying the head position. 

9. In lieu of the requirements 

specified in § 25.1439(a) at Amendment 

25–38 that pertain to isolated 

compartments and to provide a level of 

safety equivalent to that which is 

provided occupants of a small, isolated 

galley, the following equipment must be 

provided in the crew rest compartment: 

(a) At least one approved hand-held 

fire extinguisher appropriate for the 

kinds of fires likely to occur; 

(b) Two protective breathing 

equipment (PBE) devices approved to 

Technical Standard Order (TSO)–C116 

or equivalent, suitable for firefighting, or 

one PBE for each hand-held fire 

extinguisher, whichever is greater; and 

(c) One flashlight. 

Note: Additional PBEs and fire 

extinguishers in specific locations (beyond 

the minimum numbers prescribed in Special 

Condition no. 9) may be required as a result 

of any egress analysis accomplished to satisfy 

Special Condition no. 2(a). 

10. A smoke or fire detection system 

(or combination of systems) must be 

provided that monitors each occupiable 

area within the crew rest compartment, 

including those areas partitioned by 

curtains. Flight tests must be conducted 

to show compliance with this 

requirement. Each system (or 

combination of systems) must provide: 

(a) A visual indication to the flight 

deck within one minute after the start of 

a fire; 

(b) An aural warning in the crew rest 

compartment; and 

(c) A warning in the main passenger 

cabin. This warning must be readily 

detectable by a flight attendant, and 

considering the positioning of flight 

attendants throughout the main 

passenger compartment during various 

phases of flight. 

11. The crew rest compartment must 

be designed such that fires within the 

compartment can be controlled without 

a crewmember having to enter the 

compartment, or the design of the access 

provisions must allow crewmembers 

equipped for firefighting to have 

unrestricted access to the compartment. 

The time for a crewmember on the main 

deck to react to the fire alarm, to don the 

firefighting equipment, and to gain 

access must not exceed the time for the 

compartment to become smoke-filled, 

making it difficult to locate the fire 

source. 

12. The crew rest compartment design 

must incorporate a means provided to 

exclude hazardous quantities of smoke 

or extinguishing agent originating in the 

crew rest compartment from entering 

any other compartment occupied by 

crewmembers or passengers. This means 

must include the time periods during 

the evacuation of the crew rest 

compartment and, if applicable, when 

accessing the crew rest compartment to 

manually fight a fire. Smoke entering 

any other compartment occupied by 

crewmembers or passengers when the 

access to the crew rest compartment is 

opened, during an emergency 

evacuation, must dissipate within five 

minutes after the access to the crew rest 

compartment is closed. Hazardous 

quantities of smoke may not enter any 

other compartment occupied by 

crewmembers or passengers during 

subsequent access to manually fight a 


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100726 Federal Register / Vol. 89, No. 240 / Friday, December 13, 2024 / Rules and Regulations 

fire in the crew rest compartment (the 

amount of smoke entrained by a 

firefighter exiting the crew rest 

compartment through the access is not 

considered hazardous). The firefighting 

procedures must include a provision to 

ensure that all door(s) and hatch(es) at 

the crew rest compartment outlets are 

closed after evacuation of the crew rest 

compartment and during firefighting to 

minimize smoke and extinguishing 

agent from entering other occupiable 

compartments. During the 1-minute 

smoke detection time, penetration of a 

small quantity of smoke from the crew 

rest compartment into an occupied area 

is acceptable. Flight tests must be 

conducted to show compliance with 

this requirement. If a built-in fire 

extinguishing system is used in lieu of 

manual firefighting, then the fire 

extinguishing system must be designed 

so that no hazardous quantities of 

extinguishing agent will enter other 

compartments occupied by passengers 

or crew. The system must have adequate 

capacity to suppress any fire occurring 

in the crew rest compartment, 

considering the fire threat, volume of 

the compartment and the ventilation 

rate. 

13. The crew rest compartment design 

must include a supplemental oxygen 

system equivalent to that provided for 

main deck passengers for each seat and 

berth in the crew rest compartment. The 

system must provide an aural and visual 

warning to the occupants of the crew 

rest compartment to don oxygen masks 

in the event of decompression. The 

warning must activate before the cabin 

pressure altitude exceeds 15,000 feet. 

The aural warning must sound 

continuously for a minimum of five 

minutes or until a reset push button in 

the crew rest compartment is depressed. 

Procedures for crew rest occupants in 

the event of decompression must be 

established. These procedures must be 

transmitted to the operator for 

incorporation into their training 

programs and appropriate operational 

manuals. 

14. The following requirements apply 

to crew rest compartments that are 

divided into several sections by the 

installation of curtains or partitions: 

(a) To compensate for sleeping 

occupants, there must be an aural alert 

that can be heard in each section of the 

crew rest area compartment that 

accompanies automatic presentation of 

supplemental oxygen masks. A visual 

indicator that occupants must don an 

oxygen mask is required in each section 

where seats or berths are not installed. 

A minimum of two supplemental 

oxygen masks is required for each seat 

or berth. There must also be a means by 

which the oxygen masks can be 

manually deployed from the flight deck. 

(b) A placard is required adjacent to 

each curtain that visually divides or 

separates, for privacy purposes, the 

crew rest area compartment into small 

sections. The placard must require that 

the curtain(s) remains open when the 

private section it creates is unoccupied. 

(c) For each crew rest section created 

by the installation of a curtain, the 

following requirements of these special 

conditions must be met with the curtain 

open or closed: 

(1) Emergency illumination (Special 

Condition no. 5); 

(2) Emergency alarm system (Special 

Condition no. 7); 

(3) Seat belt fasten signal or return to 

seat signal as applicable (Special 

Condition no. 8); and 

(4) The smoke or fire detection system 

(Special Condition no. 10). 

(d) Crew rest compartments visually 

divided to the extent that evacuation 

could be affected must have exit signs 

that direct occupants to the primary 

stairway exit. The exit signs must be 

provided in each separate section of the 

crew rest compartment and must meet 

the requirements of § 25.812(b)(1)(i) at 

Amendment 25–58. An exit sign with 

reduced background area as described 

in Special Condition no. 4.(a) may be 

used to meet this requirement. 

(e) For sections within a crew rest 

compartment that are created by the 

installation of a partition with a door 

separating the sections, the following 

requirements of these special conditions 

must be met with the door open or 

closed: 

(1) There must be a secondary 

evacuation route from each section to 

the main deck, or alternatively, it must 

be shown that any door between the 

sections is designed to preclude anyone 

from being trapped inside the 

compartment. Removal of an 

incapacitated occupant within this area 

must be considered. A secondary 

evacuation route from a small room 

designed for only one occupant for short 

time duration, such as a changing area 

or lavatory, is not required. However, 

removal of an incapacitated occupant 

within this area must be considered. 

(2) Any door between the sections 

must be shown to be openable when 

crowded against, even when crowding 

occurs at each side of the door. 

(3) There may be no more than one 

door between any seat or berth and the 

primary stairway exit. 

(4) There must be exit signs in each 

section meeting the requirements of 

§ 25.812(b)(1)(i) at Amendment 25–58 

that direct occupants to the primary 

stairway exit. An exit sign with reduced 

background area as described in Special 

Condition no. 4.(a) may be used to meet 

this requirement. 

(5) Special Conditions no. 5 

(emergency illumination), no. 7 

(emergency alarm system), no. 8 (fasten 

seat belt signal or return to seat signal 

as applicable) and no. 10 (smoke or fire 

detection system) must be met with the 

door open or closed. 

(6) Special Conditions no. 6 (two-way 

voice communication) and no. 9 

(emergency firefighting and protective 

equipment) must be met independently 

for each separate section except for 

lavatories or other small areas that are 

not intended to be occupied for 

extended periods of time. 

15. Where a waste disposal receptacle 

is fitted, it must be equipped with a 

built-in fire extinguisher designed to 

discharge automatically upon 

occurrence of a fire in the receptacle. 

16. Materials (including finishes or 

decorative surfaces applied to the 

materials) must comply with the 

flammability requirements of § 25.853 at 

Amendment 25–66. Mattresses must 

comply with the flammability 

requirements of § 25.853(b) and (c) at 

Amendment 25–66. 

17. All lavatories within the crew rest 

are required to meet the same 

requirements as those for a lavatory 

installed on the main deck except with 

regard to Special Condition no. 10 for 

smoke detection. 

18. When a crew rest compartment is 

installed or enclosed as a removable 

module in part of a cargo compartment 

or is located directly adjacent to a cargo 

compartment without an intervening 

cargo compartment wall, the following 

applies: 

(a) Any wall of the module (container) 

forming part of the boundary of the 

reduced cargo compartment, subject to 

direct flame impingement from a fire in 

the cargo compartment and including 

any interface item between the module 

(container) and the airplane structure or 

systems, must meet the applicable 

requirements of § 25.855 at Amendment 

25–60. 

(b) Means must be provided so that 

the fire protection level of the cargo 

compartment meets the applicable 

requirements of §§ 25.855 at 

Amendment 25–60, 25.857 at 

Amendment 25–60 and 25.858 at 

Amendment 25–54 when the module 

(container) is not installed. 

(c) Use of each emergency evacuation 

route must not require occupants of the 

crew rest compartment to enter the 

cargo compartment in order to return to 

the passenger compartment. 

(d) The aural warning in Special 

Condition no. 7 must sound in the crew 


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Federal Register / Vol. 89, No. 240 / Friday, December 13, 2024 / Rules and Regulations 100727 

rest compartment in the event of a fire 

in the cargo compartment. 

19. Means must be provided to 

prevent access into the Class C cargo 

compartment during all airplane 

operations and to ensure that the 

maintenance door is closed during all 

airplane flight operations. 

20. All enclosed stowage 

compartments within the crew rest that 

are not limited to stowage of emergency 

equipment or airplane-supplied 

equipment (e.g., bedding) must meet the 

design criteria given in the table below. 

As indicated by the table below, this 

special condition does not address 

enclosed stowage compartments greater 

than 200 ft3 in interior volume. The inflight accessibility of very large, 

enclosed stowage compartments and the 

subsequent impact on the 

crewmembers’ ability to effectively 

reach any part of the compartment with 

the contents of a hand fire extinguisher 

will require additional fire protection 

considerations similar to those required 

for inaccessible compartments such as 

Class C cargo compartments. 

Fire protection features 

Stowage compartment interior volumes 

Less than 25 ft3 25 ft3 to 57 ft3 57 ft3 to 200 ft3

Materials of Construction 1 ............. Yes ................................................ Yes ................................................ Yes. 

Detectors 2 ...................................... No ................................................. Yes ................................................ Yes. 

Liner 3 ............................................. No ................................................. No ................................................. Yes. 

Locating Device 4 ........................... No ................................................. Yes ................................................ Yes. 

1 Material: The material used to construct each enclosed stowage compartment must at least be fire resistant and must meet the flammability

standards established for interior components per the requirements of § 25.853. For compartments less than 25 ft3 in interior volume, the design 

must ensure the ability to contain a fire likely to occur within the compartment under normal use. 2 Detectors: Enclosed stowage compartments equal to or exceeding 25 ft3 in interior volume must be provided with a smoke or fire detection 

system to ensure that a fire can be detected within a one-minute detection time. Flight tests must be conducted to show compliance with this requirement. Each system (or systems) must provide: 

(a) A visual indication in the flight deck within one minute after the start of a fire; 

(b) An aural warning in the crew rest compartment; and 

(c) A warning in the main passenger cabin. This warning must be readily detectable by a flight attendant, taking into consideration the positioning of flight attendants throughout the main passenger compartment during various phases of flight. 3 Liner: If it can be shown that the material used to construct the stowage compartment meets the flammability requirements of a liner for a 

Class B cargo compartment, then no liner would be required for enclosed stowage compartments equal to or greater than 25 ft3 in interior volume but less than 57 ft3 in interior volume. For all enclosed stowage compartments equal to or greater than 57 ft3 in interior volume but less than 

or equal to 200 ft3, a liner must be provided that meets the requirements of § 25.855 at Amendment 25–60 for a class B cargo compartment. 4 Location Detector: Crew rest areas which contain enclosed stowage compartments exceeding 25 ft3 interior volume and which are located 

away from one central location such as the entry to the crew rest area or a common area within the crew rest area would require additional fire 

protection features and/or devices to assist the firefighter in determining the location of a fire. 

Issued in Kansas City, Missouri, on 

December 9, 2024. 

Patrick R. Mullen, 

Manager, Technical Policy Branch, Policy and 

Standards Division, Aircraft Certification 

Service. 

[FR Doc. 2024–29432 Filed 12–12–24; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. FAA–2024–2387; Special 

Conditions No. 25–871–SC] 

Special Conditions: Airbus Models 

A321 neo ACF and A321 neo XLR; 

Single-Occupant Oblique Seats With 

Pretensioner Restraint Systems 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions; request 

for comments. 

SUMMARY: These special conditions are 

issued for the Airbus Model A321 neo 

ACF and A321 neo XLR airplanes. 

These airplanes have a novel or unusual 

design feature when compared to the 

state of technology envisioned in the 

airworthiness standards for transport 

category airplanes. This design feature 

incorporates oblique (side-facing) 

passenger seats which may include a 3- 

point restraint system with 

pretensioner. These oblique seats may 

be installed at an angle of 18 to 45 

degrees to the aircraft centerline and 

have surrounding furniture that 

introduces occupant and loading 

concerns. The applicable airworthiness 

regulations do not contain adequate or 

appropriate safety standards for this 

design feature. These special conditions 

contain the additional safety standards 

that the Administrator considers 

necessary to establish a level of safety 

equivalent to that established by the 

existing airworthiness standards. 

DATES: This action is effective on Airbus 

S.A.S. on December 13, 2024. Send 

comments on or before January 27, 

2025. 

ADDRESSES: Send comments identified 

by Docket No. FAA–2024–2387 using 

any of the following methods: 

• Federal eRegulations Portal: Go to 

www.regulations.gov and follow the 

online instructions for sending your 

comments electronically. 

• Mail: Send comments to Docket 

Operations, M–30, U.S. Department of 

Transportation (DOT), 1200 New Jersey 

Avenue SE, Room W12–140, West 

Building Ground Floor, Washington, DC 

20590–0001. 

• Hand Delivery or Courier: Take 

comments to Docket Operations in 

Room W12–140 of the West Building 

Ground Floor at 1200 New Jersey 

Avenue SE, Washington, DC, between 9 

a.m. and 5 p.m., Monday through 

Friday, except Federal holidays. 

• Fax: Fax comments to Docket 

Operations at 202–493–2251. 

Docket: Background documents or 

comments received may be read at 

www.regulations.gov at any time. 

Follow the online instructions for 

accessing the docket or go to Docket 

Operations in Room W12–140 of the 

West Building Ground Floor at 1200 

New Jersey Avenue SE, Washington, 

DC, between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

FOR FURTHER INFORMATION CONTACT: 

Shannon Lennon, Cabin Safety Section, 

AIR–624, Technical Policy Branch, 

Policy and Standards Division, Aircraft 

Certification Service, Federal Aviation 

Administration, 2200 South 216th 

Street, Des Moines, Washington 98198; 

telephone (206) 231–3209; fax (206) 

231–3827; email Shannon.Lennon@

faa.gov. 

SUPPLEMENTARY INFORMATION: The 

substance of these special conditions 

has been published in the Federal 


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