[Federal Register Volume 90, Number 113 (Friday, June 13, 2025)]
[Rules and Regulations]
[Pages 24955-24959]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-10837]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2024-0190; Special Conditions No. 25-877-SC]
Special Conditions: The Boeing Company, Boeing Model 747-8 Series
Airplane; Short-Term Occupancy of Lower Lobe During Flight and
Installation of Stairway Between Main Deck and Lower-Lobe
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions.
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SUMMARY: These special conditions are issued for the The Boeing Company
(Boeing) Model 747-8 series airplane. This airplane, as modified by
Boeing, 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 the installation
of stairs for flightcrew to access the forward and aft lower lobe
compartments during flight. These compartments will have two main
functions: storage of service items and that of a Class C 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 July 14, 2025.
FOR FURTHER INFORMATION CONTACT: Alan Sinclair, Technical Policy
Branch, Policy and Standards Division, Aircraft Certification Service,
Federal Aviation Administration, FAA Seattle Headquarters, 2200 South
216th Street, Des Moines, Washington 98198; telephone and fax 206-231-
3215; email: [email protected].
SUPPLEMENTARY INFORMATION:
Background
On July 2, 2018, Boeing applied for a supplemental type certificate
(STC) for the installation of stairs for inflight flightcrew to access
the forward and aft lower lobe compartments that will have two main
functions: access of service items that have been stored and that of a
Class C cargo compartment in the Model 747-8 series airplane. The
modified Boeing Model 747-8 series airplane, which is a derivative of
the Model 747-8F series airplane currently approved under Type
Certificate No. A20WE, is a four-engine, transport category airplane
with a VIP interior configuration, not for common carriage, seating for
93 passengers and 15 flightcrew, and a maximum takeoff weight of
987,000 pounds.
Type Certification Basis
Under the provisions of title 14, Code of Federal Regulations (14
CFR) 21.101, Boeing must show that changes to the Boeing Model 747-8
series airplane, as changed, continues to meet the applicable
provisions of the regulations listed in Type Certificate No. A20WE 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 Boeing Model 747-8 series
airplanes because of a novel or unusual design feature, special
conditions are prescribed under the provisions of Sec. 21.16.
Special conditions are initially applicable to the model for which
they are issued. Should the applicant apply for an STC 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 Sec. 21.101.
In addition to the applicable airworthiness regulations and special
conditions, the Boeing Model 747-8 series airplanes must comply with
the exhaust-emission 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 Sec. 11.38, and they become part of
[[Page 24956]]
the type certification basis under Sec. 21.101.
Novel or Unusual Design Feature
Certain Boeing Model 747-8 series airplanes will incorporate the
following novel or unusual design feature:
The installation of stairs for flightcrew to access the forward and
aft lower lobe compartments during flight. The compartments will have
two main functions: storage of service items and that of a Class C
cargo compartment.
Discussion
Existing regulations address service areas and Class C cargo
compartments independently, but do not address compartments that have
both uses. A service compartment can be occupied, and a Class C cargo
compartment cannot. Further, firefighting is dealt with differently in
each compartment. The crew fights a fire in a service compartment and a
flooding suppression system is used to fight a fire in a Class C cargo
compartment.
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. 25-24-01-
SC, for the Boeing Model 747-8 airplane airplane, which was published
in the Federal Register on November 29, 2024 (89 FR 94620).
The FAA received one response, from an individual. The commenter
recommends that the FAA clarify in the final special conditions whether
there will be a suppression system in the service compartment or if the
crew is to fight a fire in this area.
There will be a fire suppression system in the service compartment.
As explained in the Notice of Proposed Special Conditions, this project
modifies the lower lobe forward and aft Class C cargo compartments to
function as storage of service items (also known as the service area in
this document) that can be used during flight, and for other cargo or
baggage that is the traditional function of a Class C cargo
compartment. The service areas are within the Class C cargo
compartments and as such, these service areas must be covered by the
Class C cargo compartment built-in fire extinguishing or suppression
system per 14 CFR 25.857(c)(2).
In addition, these special conditions address only the aspects of
this novel or unusual design feature that were not envisaged by the
current airworthiness standards for transport category airplanes. All
other applicable regulations for transport category airplanes apply to
this project and are not included in these special conditions. For
example, Class C cargo compartments are required to incorporate an
approved built-in fire extinguishing or suppression system controllable
from the cockpit per 14 CFR 25.857(c)(2).
Further, Title 14 CFR 91.505(b) requires that crewmembers must be
familiar with emergency equipment and with the procedures for the use
of that equipment in an emergency situation (e.g., fighting a fire in
an area on the airplane as appropriate for such action, such as the
cabin, a galley, etc.). Those procedures are required by 14 CFR 121.135
to be included in applicable crew manuals for all flight crew and cabin
crew members on transport category airplanes and are required for
certification. Therefore, the FAA did not include those regulations or
include the associated actions in these special conditions.
The commenter also recommends that ``. . . the procedure for
dealing with a fire that spreads across the entire lower lobe should be
clarified. If a fire starting in the cargo hold were to spread to the
service compartment before fire door activation and suppressant release
in the cargo area, the flight crew could be unnecessarily endangered by
having to re-enter the lower lobe and fight the spread of the fire
after the suppressant was released in the cargo area.''
The FAA concurs that normal, abnormal, and emergency procedures
must be provided as required in 14 CFR 25.1585, 121.133 and 121.135.
However, these procedures are developed upon completion of a failure
hazard assessment and system safety evaluations that consider the
likelihood of the event occurring (i.e., the probability of the
failure/fire scenario).
Historically, the FAA has considered the likelihood of multiple
fires in separate compartments on a transport category airplane to be
extremely improbable. The lower lobe Class C cargo compartments are
physically separate from each other and from the access stairwell.
The boundaries of the Class C cargo compartments (i.e., composed of
liner material and hardwall surfaces) must meet the flammability and
heat resistance requirements in 14 CFR 25.855 and Appendix F. The FAA
finds that these requirements are appropriate based upon in-service
experience. Access doors are provided for each Class C cargo
compartment in this airplane design and those access doors must meet
the requirements in 14 CFR 25.855.
In addition, the crewmembers who access the lower lobe Class C
cargo compartments are required to be trained and expected to follow
procedures that ensure the access doors must remain closed except when
a crewmember is entering or exiting the compartment. For the reasons
explained above, the FAA finds that the scenario the commenter
describes is extremely improbable, and did not change these special
conditions as a result of this comment.
Applicability
As discussed above, these special conditions are applicable to the
Boeing Model 747-8 airplanes as modified by Boeing. Should the
applicant apply for a STC 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.
Conclusion
This action affects only a certain novel or unusual design feature
on one model; Boeing Model 747-8 series of airplanes. 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 the Boeing Model 747-8 series
airplane.
Requirements Specific to Lower Lobe Access
(a) Alerts and indications are required in the lower lobe
compartments to indicate decompression, smoke/fire detection, and the
need to return to one's seat. The definition for alert categorization
must be consistent with 14 CFR 25.1322.
(1) There must be a flight deck indication to advise the flightcrew
when the lower lobe service/cargo compartment(s) are occupied. The
indication must be accompanied by a
[[Page 24957]]
placard or message in the flight deck indicating someone is in the
lower lobe compartment(s). The flight deck indication must be initiated
automatically when the compartments become occupied, without input from
the occupying flightcrew other than required to gain access. The flight
deck indication must be canceled automatically when the compartment(s)
are no longer occupied, and the means of access is returned to the
unoccupied configuration.
(i) There must be flight deck indication to advise the flightcrew
that the in-flight accessible doors to the lower lobe compartments are
closed prior to initiation of the fire suppression system.
(2) There must be an ``on/off'' visual alert light located outside
and on or near the access doors to each lower lobe service/cargo
compartment with a placard stating, ``When light is illuminated
entrance is prohibited'' (or similar words). The alert is to be
automatic in the event of decompression, smoke/fire detection or
anytime the compartment visual alerting system is activated.
(3) A flightcrew operated visual alerting system, which is
recognized in accessible areas within the lower lobe compartment(s),
must be installed to indicate, during turbulence, that persons must
return to their seats. Appropriate procedures and limitations (if
required) must be established to ensure that the flightcrew alerting
systems notify the occupants to return to their seats at the onset of
turbulence and prior to taxi, takeoff and landing.
(4) An automatically activated aural and visual decompression
alerting system must be present and immediately recognizable in
accessible areas of the lower lobe compartments to notify occupants
when to don oxygen masks.
(5) An automatically activated aural and visual alerting system,
which is recognized in the lower lobe compartment(s), must be
installed. This aural and visual alerting system is to indicate that,
in the event of smoke detection in the lower lobe compartment(s),
persons must don their oxygen masks and initiate oxygen flow, exit the
compartment, ensure that the door is closed (smoke barrier) and that
communication with the flight deck is established. Entry must not be
allowed during flight after release of fire suppressant.
(6) These alerting requirements must be distinctive and effective,
and:
(i) Visual alerts must be visible from all occupant locations
during all expected operational conditions including a rapid
decompression where moisture in the air may condense.
(ii) Aural alerts must be loud enough to be heard during all
expected operational conditions including a rapid decompression where
the ambient noise level will increase.
(iii) If there are two or more alerts that an occupant may hear or
is expected to respond to, there must be an automatic visual alert in
addition to the automatic aural alert. There must be training in the
sound of the alerting system, the meaning of the alerting system, and
the response to the signal (i.e., procedures for donning the masks and
activating the flow of oxygen).
(b) Placards
(1) There must be appropriate placards installed inside and outside
each access door to the lower lobe compartment(s) to indicate:
(i) The maximum number of occupants allowed, or number of occupants
required, as applicable to the compartment.
(ii) Occupancy is restricted to crewmembers trained in the
procedures of the lower lobe compartment(s).
(iii) Occupancy is prohibited during taxi, takeoff, and landing,
and whilst the fire suppression system is activated.
(iv) The access door must remain closed except when someone is
entering or exiting the compartment.
(v) Occupancy of the compartment should be of minimum duration.
(vi) Anyone entering the lower lobe compartment(s) during flight
must carry portable oxygen equipment for the entire time that they are
in the compartment.
(2) There must be appropriate placards located conspicuously on or
near each lower lobe compartment exit defining the location and
operating instructions for each evacuation route. Placards must be
readable from a distance of 30 inches under emergency lighting
conditions.
(3) There must be a placard located adjacent to the visual alert
light required by condition (a) (2) of these special conditions that
state, ``When light is illuminated, entrance is prohibited'' (or
similar words).
(4) In addition to the above special conditions, the following
additional placards must be included for an electronics equipment (E/E)
Bay:
(i) No stowage allowed within an E/E Bay.
(ii) In-flight access for panels/cabinets not designed to be used
in-flight is prohibited.
(iii) Provided the section (g) in-flight maintenance requirements
in instructions for continued airworthiness (ICA) are met, placarding
must declare that ``Entrance is prohibited except by permission of the
pilot in command'' (or similar words).
(iv) ``Access is not permitted during flight'' if the in-flight
maintenance requirements in ICA section (g) are not met.
(v) A placard must be installed on all access panels and doors
within lower lobe compartments prohibiting use of those that are not
intended for use in flight.
(c) Equipment: In lieu of that required by Sec. Sec. 25.819,
25.851(a), 25.1439(a) and 25.1447(c) the following equipment is
required:
(1) There must be a portable oxygen bottle with mask attached to it
meeting the requirements Sec. 25.1439(b)(1), (b)(2)(i) and (b)(4) for
each crewmember occupying the lower lobe compartment(s). The equipment
must be mounted outside each access door to the lower lobe service/
cargo compartment(s). The equipment and system must be designed to
prevent any inward leakage to the inside of the device and prevent any
outward leakage causing significant increase in the oxygen content of
the local atmosphere (i.e., full face mask type). A portable oxygen
bottle must be carried by each crewmember who is occupying the lower
lobe service/cargo compartment. The portable oxygen bottle must also
meet the minimum performance requirements of Sec. 25.1443(a) or (b),
or the equipment must be shown to protect the occupant from hypoxia at
an activity level required to return to a seat on the main deck where
oxygen is available following a rapid decompression.
(2) In addition to the emergency illumination required by Sec.
25.819(a), at least two flashlights, each equipped with a locator
light, must be provided. One flashlight must be located adjacent to
each emergency exit and entrance in the lower lobe compartment(s).
(3) In addition to the evacuation route requirements of Sec.
25.819(a), all entrances and exits from the lower lobe service/cargo
compartment must be capable of being closed after entering and exiting
and, after closing, must prevent hazardous quantities of smoke, flames,
or fire suppressant agent from entering any compartments occupied by
passengers or crew and must prevent loss of fire suppressant agent when
activated.
(4) In lieu of the emergency equipment required by Sec. Sec.
25.851(a) and 25.1439(a), when the procedures allow for a single
occupant in a potential ``dead end'' volume further than 5 feet from an
exit in the lower lobe compartment(s) there must be a readily
accessible fire extinguisher, appropriate
[[Page 24958]]
to the types and kinds of fires that may occur.
(5) A means must be in place to preclude anyone from being trapped
inside the lower lobe compartment(s). If a locking mechanism is
installed in the door, it must be capable of being unlocked from the
either side of the door without the aid of any tools.
(6) A means must be in place to restrict access and prevent
inadvertent damage to critical aircraft systems and equipment located
within the compartment during flight.
(7) There must be a means to communicate with the flight deck from
within the E/E Bay.
(d) Training: Training manuals and training must include:
(1) Use and actions associated with aural and visual alerts and
placards specified herein.
(2) Entering and exiting the lower lobe compartment(s), including
emergency exiting.
(3) Checking the oxygen bottle pressure for adequacy prior to
entering the lower lobe service/cargo compartment.
(4) Carrying the oxygen bottle when entering the lower lobe
compartment(s) and using the bottle in emergency situations.
(5) Maintaining exit path aisle and access for the evacuation
routes.
(6) Identification of equipment related hazards such as the
potential for electric shock and burns.
(7) Limiting the occupancy for duration of the required tasks.
(e) Procedures
(1) A procedure must be established to ensure that the appropriate
actions are taken in the event of smoke/fire detection. These actions
are to include evacuation of the lower lobe compartments if occupied,
communication with flight deck, determination of the event severity and
the closure of the compartment doors for compartment sealing. These
actions ensure the fire barriers (i.e., doors) are closed prior to
release of fire suppressant agent in the cargo compartments. Reentry
into the lower lobe service/cargo compartments after a smoke/fire
detection event would only be allowed by the pilot in command, via
controlled procedures.
(2) A procedure must be established to ensure that required
equipment, such as portable oxygen, fire extinguishers, protective
breathing equipment, and warning light are functional prior to takeoff.
(f) Limitations of Special Condition
(1) An FAA approved cabin crew manual requiring the cabin crew
verify the lower lobe compartment(s) are not occupied during taxi,
takeoff, landing, or after fire suppression activation must be created.
The cabin crew manual must include instructions for allowing access;
procedures for fire/smoke detection/firefighting; procedures for
decompression. The cabin crew manual must be specified by the master
drawing list and called out on the description of type design change
section of the STC.
(2) The airplane flight manual (AFM) supplement must include
instructions for: allowing access; procedures for fire/smoke detection/
firefighting; and procedures for decompression.
(3) The weight and balance manual must include cargo loading
restrictions to maintain escape paths.
(g) Instructions for Continued Airworthiness (ICAs)
(1) The ICAs must contain appropriate procedures to ensure
maintenance can be safely accomplished in-flight.
(i) The ICA supplement must contain instructions that highlight the
special considerations associated with in-flight maintenance. This
content includes any assumptions or requirements for compliance with
Sec. Sec. 25.1309, 25.1360, 25.1529 and 25.1721.
(ii) The ICAs must establish an appropriate foreign object damage
(FOD) control process for performing maintenance in-flight. The hazards
associated with FOD may be mitigated by design and existing FOD control
processes.
(iii) The ICAs must establish an appropriate lock-out/tag-out
procedure for performing maintenance in-flight. A new single lock-out/
tag-out procedure may be created for both ground and flight.
Requirements Specific to the Stairway
(h) The stairway must have essentially straight route segments with
a landing at each significant change in segment direction.
(i) The stairway must have essentially rectangular treads.
(j) The stairway must accommodate the carriage of an incapacitated
occupant from the lower deck to the main deck. The crewmember
procedures for such carriage must be established and included in the
AFM.
(k) In normal operation, the general illumination level must not be
less than 0.05 foot-candles when measured along the center lines of
each tread and landing.
(l) The stairway must have a handrail on at least one side to allow
occupants to steady themselves during moderate turbulence in flight.
The handrail(s) must be constructed so there is no obstruction on them
that will cause the user to release his/her grip or hinder the
continuous movement of the hands along the handrail. The design must
accommodate the stature of a 5th percentile female and a 95th
percentile male.
(m) The public address system must be intelligible in the stairway
during all flight phases.
(n) ``Return to seat'' signs must be installed and visible in the
stairway both going up and down and at the stairway entrances.
(o) Appropriate placards must be located outside each main deck
entrance to the lower lobe access stairs to indicate:
(1) The maximum number of occupants allowed in flight.
(2) Occupancy during flight is restricted to crewmembers that are
trained in the procedures for the lower lobe compartments.
(3) Occupancy is prohibited during taxi, take-off, and landing.
(4) The stowage of cargo or passenger baggage is not allowed in the
stair enclosure. This placard is also required at each stair landing.
(p) Passengers must be prevented from entering the stairway in the
event of an emergency or when no flight attendant is present.
(q) The means required by condition (p) must be capable of being
quickly opened from inside the stairway, even when crowding occurs at
the passenger cabin side of the stair entrance.
(r) A means must be in place to preclude anyone from being trapped
inside the stairway. If a locking mechanism is installed, it must be
capable of being unlocked from either side without the aid of tools.
(s) There must be appropriate placards conspicuously located as
follows:
(1) Inside the stairs on or near each exit to the main deck
defining the operating instructions for the door.
(2) On the cabin side, when the door is closed, no higher than 4
feet from the floor, indicating that the door is not an emergency exit.
(t) For the placards required by condition (s) the following
applies:
(1) Placards must be readable from a distance of 30 inches under
emergency lighting conditions.
(2) Placards must be illuminated to at least 160 micro-lamberts
under emergency lighting conditions.
(u) There shall be a means (visible and audible) to notify an
occupant of the stairway of the need to don supplemental oxygen
equipment in the event of a decompression. The aural and visual alerts
must activate before the cabin pressure altitude exceeds 15,000 feet.
[[Page 24959]]
(v) A means must be available, in the event of failure of the
airplane's main power system, or of the normal stairway lighting
system, for emergency illumination to be automatically provided in the
stairway.
(1) This emergency illumination must be independent of the main
lighting system.
(2) The sources of general 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.
(3) Emergency illumination must be provided so that, when measured
along the centerlines of each tread and landing, the illumination is
not less than 0.05 foot-candles.
Issued in in Kansas City, Missouri, on June 4, 2025.
Patrick R. Mullen,
Manager, Technical Policy Branch, Policy and Standards Division,
Aircraft Certification Service.
[FR Doc. 2025-10837 Filed 6-12-25; 8:45 am]
BILLING CODE 4910-13-P