[Federal Register Volume 89, Number 134 (Friday, July 12, 2024)]
[Rules and Regulations]
[Pages 57070-57073]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-15266]



[[Page 57070]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2024-1328; Special Conditions No. 25-866-SC]


Special Conditions: Gulfstream Aerospace Corporation (Gulfstream) 
Model GVII-G400 Airplane; Seats With Inflatable Lapbelts

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final special conditions, request for comment.

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SUMMARY: These special conditions are issued for the Gulfstream Model 
GVII-G400 airplane. This airplane 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 seating with inflatable lapbelts. 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 Gulfstream on July 12, 2024. Send 
comments on or before August 26, 2024.

ADDRESSES: Send comments identified by Docket No. FAA-2024-1328 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: Myra Kuck, Cabin Safety, AIR-624, 
Technical Policy Branch, Policy and Standards Division, Aircraft 
Certification Service, Federal Aviation Administration, 3960 Paramount 
Blvd., Suite 100, Lakewood, CA 90712, telephone and fax (405) 666-1059; 
email [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The substance of these special conditions has been published in the 
Federal Register for public comment in several prior instances with no 
substantive comments received. Therefore, the FAA finds, pursuant to 14 
CFR 11.38(b), that new comments are unlikely, and notice and comment 
prior to this publication are unnecessary.

Privacy

    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in title 
14, Code of Federal Regulations (14 CFR), Sec.  11.35, the FAA will 
post all comments received without change to www.regulations.gov, 
including any personal information you provide. The FAA will also post 
a report summarizing each substantive verbal contact received about 
these special conditions.

Confidential Business Information

    Confidential Business Information (CBI) is commercial or financial 
information that is both customarily and actually treated as private by 
its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), 
CBI is exempt from public disclosure. If your comments responsive to 
these special conditions contain commercial or financial information 
that is customarily treated as private, that you actually treat as 
private, and that is relevant or responsive to these special 
conditions, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and the indicated comments will not be 
placed in the public docket of these proposed special conditions. Send 
submissions containing CBI to the individual listed in the FOR FURTHER 
INFORMATION CONTACT section above. Comments the FAA receives, which are 
not specifically designated as CBI, will be placed in the public docket 
for these proposed special conditions.

Comments Invited

    The FAA invites interested people to take part in this rulemaking 
by sending written comments, data, or views. The most helpful comments 
reference a specific portion of the special conditions, explain the 
reason for any recommended change, and include supporting data.
    The FAA will consider all comments received by the closing date for 
comments, and will consider comments filed late if it is possible to do 
so without incurring delay. The FAA may change these special conditions 
based on the comments received.

Background

    On December 15, 2020, Gulfstream applied for an amendment to Type 
Certificate No. T00021AT to include the new Model GVII-G400. The 
Gulfstream Model GVII-G400 airplane, which is a derivative of the Model 
GVII-G500 currently approved under Type Certificate No. T00021AT, is a 
twin-engine business jet, with a maximum seating capacity for 19 
passengers, and a maximum take-off weight of 73,500 pounds.

Type Certification Basis

    Under the provisions of title 14, Code of Federal Regulations (14 
CFR), Sec.  21.101, Gulfstream must show that the Model GVII-G400 
airplane meets the applicable provisions of the regulations listed in 
Type Certificate No. T00021AT, 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 Gulfstream Model GVII-G400 
airplane 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 type certificate for that model be amended 
later to include any other model that incorporates the same novel or 
unusual design feature, or should any other model already included on 
the same type certificate be modified 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 Gulfstream Model GVII-

[[Page 57071]]

G400 airplane 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 14 CFR 11.38, and they become part of the type 
certification basis under Sec.  21.101.

Novel or Unusual Design Features

    The Gulfstream Model GVII-G400 airplane will incorporate the 
following novel or unusual design feature:
    Seating with inflatable lapbelts.

Discussion

    An inflatable lap belt is designed to limit occupant forward 
excursion in the event of an accident, and thereby reduce the potential 
for head injury. The inflatable lap belt behaves similarly to an 
automotive inflatable airbag, but in this case the airbag is integrated 
into the lap belt and inflates away from the seated occupant. While 
inflatable airbags are now standard in the automotive industry, the use 
of an inflatable lap belt is novel for commercial aviation.
    Occupants must be protected from head injury, as required by Sec.  
25.785, either by eliminating any injurious object within the striking 
radius of the head, or by installing padding. Traditionally, this has 
required either a setback of 35 inches from any bulkhead or other rigid 
interior feature or, where not practical, the installation of specified 
types of padding. The relative effectiveness of these established means 
of injury protection was not quantified. With the adoption of Amendment 
25-64 to part 25, specifically Sec.  25.562, a new standard was created 
that quantifies required head-injury protection.
    Each seat-type design approved for crew or passenger occupancy 
during takeoff and landing, as required by Sec.  25.562, must 
successfully complete dynamic tests or be demonstrated by rational 
analysis based on dynamic tests of a similar type seat. In particular, 
the regulations require that persons not suffer serious head injury 
under the conditions specified in the tests, and that protection must 
be provided, or the seat be designed, so that head impact does not 
exceed a (head injury criteria) HIC value of 1,000 units. While the 
test conditions described for HIC are detailed and specific, it is the 
intent of the requirement that an adequate level of head-injury 
protection be provided for passengers in a severe crash.
    Because Sec. Sec.  25.562 and 25.785 and associated guidance do not 
adequately address seats with inflatable lap belts, the FAA recognizes 
that appropriate pass/fail criteria need to be developed that fully 
address the safety concerns specific to occupants of these seats.
    The inflatable lap belt has two potential advantages over other 
means of head-impact protection. First, it can provide significantly 
greater protection than would be expected with energy-absorbing pads, 
and second, it can provide essentially equivalent protection for 
occupants of all stature. These are significant advantages from a 
safety standpoint because such devices will likely provide a level of 
safety that exceeds the minimum standards of part 25. Conversely, 
inflatable lap belts in general are active systems and must be relied 
upon to activate properly when needed, as opposed to an energy-
absorbing pad or upper torso restraint that is passive and always 
available. Therefore, the potential advantages must be balanced against 
this and other potential disadvantages to develop standards for this 
design feature.
    The FAA has considered the installation of inflatable lap belts to 
have two primary safety concerns: First, that they perform properly 
under foreseeable operating conditions; and second, that they do not 
perform in a manner or at such times as would constitute a hazard to 
the airplane or occupants. This latter point has the potential to be 
the more rigorous of the requirements, owing to the active nature of 
the system.
    The inflatable lap belt will rely on electronic sensors for 
signaling, and will employ an automatic inflation mechanism for 
activation, so that it is available when needed. These same devices 
could be susceptible to inadvertent activation, causing deployment in a 
potentially unsafe manner. The consequences of such deployment must be 
considered in establishing the reliability of the system. An applicant 
must substantiate that the effects of an inadvertent deployment in 
flight are either not a hazard to the airplane, or that such deployment 
is an extremely improbable occurrence (less than 10-9 per 
flight hour). The effect of an inadvertent deployment on a passenger or 
crewmember that might be positioned close to the inflatable lap belt 
should also be considered. The person could be either standing or 
sitting. A minimum reliability level will have to be established for 
this case, depending upon the consequences, even if the effect on the 
airplane is negligible.
    Because the inflatable lap belt is essentially a single-use device, 
it could potentially deploy under crash conditions that are not 
sufficiently severe as to require head-injury protection from the 
inflatable lap belt. And because an actual crash is frequently composed 
of a series of impacts before the airplane comes to rest, this could 
render the inflatable lap belt useless if a larger impact follows the 
initial impact. This situation does not exist with energy-absorbing 
pads or upper-torso restraints, which tend to provide continuous 
protection regardless of severity or number of impacts in a crash 
event. Therefore, the inflatable lap-belt installation should be such 
that the inflatable lap belt will provide protection when it is 
required, by not expending its protection during a less-severe impact. 
Also, it is possible to have several large impact events during the 
course of a crash, but there will be no requirement for the inflatable 
lap belt to provide protection for multiple impacts. An acceptable 
method to show an inflatable lap belt deploys at an appropriate time is 
to conduct threshold testing to demonstrate the device trigger G-level 
is high enough to prevent false activations and low enough to deploy 
the airbag in time to protect the occupant. A threshold pulse that is 
scaled down from the required 16g, 90 ms triangular pulse in Sec.  
25.562 is used. The FAA considers a suitable trigger force and time to 
fire range of 7.5g with 1.5 m/s at 42 ms and 9.3g with 2.4 m/s at 52 ms 
to be acceptable. FAA TSO-C127c, Appendix 1 provides additional 
information on sensor-driven restraint systems where it modifies 
AS8049C by adding subsection 5.3.1.5.
    Since each occupant's restraint system provides protection for that 
occupant only, the installation must address seats that are unoccupied. 
It will be necessary for Gulfstream to show that the required 
protection is provided for each occupant regardless of the number of 
occupied seats, considering that unoccupied seats may have lap belts 
that are active.
    The inflatable lap belt should be effective for a wide range of 
occupants. The FAA has historically considered the range from the 5th 
percentile female to the 95th percentile male as the range of occupants 
that must be taken into account. In this case, the FAA is proposing 
consideration of a broader range of occupants due to the nature of the 
lap-belt installation and its close proximity to the occupant. In a 
similar vein, these persons could have assumed the brace position for 
those accidents where an impact is anticipated. Test data indicate that 
occupants in the brace position do not require supplemental protection, 
so it would not be necessary to show that the inflatable lap belt will 
enhance the brace position. However, the inflatable lap belt must not

[[Page 57072]]

introduce a hazard when it is deployed into a seated, braced occupant.
    Another area of concern is the use of seats so equipped by 
children, whether lap-held, in approved child safety seats, or 
occupying the seat directly. Similarly, if the seat is occupied by a 
pregnant woman, the installation should address such usage, either by 
demonstrating that it will function properly, or by adding appropriate 
limitation on usage.
    Since the inflatable lap belt will be electrically powered, there 
is the possibility that the system could fail due to a separation in 
the fuselage. Since this system is intended as crash/post-crash 
protection means, failure to deploy due to fuselage separation is not 
acceptable. As with emergency lighting, the system should function 
properly if such a separation occurs at any point in the fuselage. As 
required by Sec.  25.1353(a), operation of the existing aircraft 
electrical equipment should not adversely impact the function of the 
inflatable lap belt under all foreseeable conditions.
    Because the inflatable lap belt is likely to have a large volume 
displacement, the inflated bag could potentially impede egress of 
passengers. However, the lap-belt bag deflates to absorb energy, so it 
is likely that an inflatable lap belt would be deflated by the time 
passengers begin to leave their seats. Nonetheless, it is appropriate 
to specify a time interval after which the inflatable lap belt may not 
impede rapid egress. The maximum time allowed for an exit to open fully 
after actuation is 10 seconds, according to Sec.  25.809(b)(2). 
Therefore, the FAA has established 10 seconds as the time interval that 
the inflatable lap belt must not impede rapid egress from the seat 
after it is deployed. In actuality, it is unlikely that a flight 
attendant would prepare an exit this quickly in an accident severe 
enough to warrant deployment of the inflatable lap belt. The inflatable 
lap belt will likely deflate much more quickly than 10 seconds.
    Inflatable lap belts must not impede access to, or opening of, 
exits. The applicant must show compliance with the exit opening and 
access requirements of Sec. Sec.  25.809 and 25.813 with representative 
inflatable lap belts in both the pre- and post-deployed conditions. The 
evaluation must include review for obstructions in the egress path and 
any interferences in opening the exit and must consider each unique 
interior configuration. Additional project specific guidance may be 
needed if inflatable lap belts are installed at overwing exit rows.
    Part I of appendix F to part 25 specifies the flammability 
requirements for interior materials and components. There is no 
reference to inflatable restraint systems in appendix F because such 
devices did not exist at the time the flammability requirements were 
written. The existing requirements are based on both material types, as 
well as use, and have been specified in light of the state-of-the-art 
of materials available to perform a given function. In the absence of a 
specific reference, the default requirement would be for the type of 
material used to construct the inflatable restraint, which is a fabric 
in this case. However, in writing a special condition, the FAA must 
also consider the use of the material, and whether the default 
requirement is appropriate. In this case, the specialized function of 
the inflatable restraint means that highly specialized materials are 
needed. The standard normally applied to fabrics is a 12-second 
vertical ignition test. However, materials that meet this standard do 
not perform adequately as inflatable restraints. Since the safety 
benefit of the inflatable restraint is very significant, the 
flammability standard appropriate for these devices should not screen 
out suitable materials, thereby effectively eliminating use of 
inflatable restraints. The FAA needs to establish a balance between the 
safety benefit of the inflatable restraint, and its flammability 
performance. At this time, the 2.5-inch per minute horizontal test as 
defined in 14 CFR part 25, appendix F, part I, paragraph (b)(5) is 
considered to provide that balance. As the technology in materials 
progresses (which is expected), the FAA may change this standard in 
subsequent special conditions to account for improved materials.
    The potential for an inadvertent deployment could be increased as a 
result of conditions in service. The installation must take into 
account wear and tear so that the likelihood of an inadvertent 
deployment is not increased to an unacceptable level. In this context, 
an appropriate inspection interval and self-test capability are 
considered necessary. In addition, outside influences such as lightning 
and high intensity radiated fields (HIRF) may also contribute to or 
cause inadvertent deployment. Existing regulations regarding lightning, 
Sec.  25.1316, and high-intensity radiated fields (HIRF), Sec.  25.1317 
for the GVII-G400 aircraft are applicable. It must be verified that 
electromagnetic interference present, under foreseeable operating 
conditions, will not affect the function of the inflatable lap belt or 
cause inadvertent deployment. Finally, the inflatable lap belt 
installation should be protected from the effects of fire, so that an 
additional hazard is not created by, for example, a rupture of the 
pyrotechnic squib.
    Note that the special conditions are applicable to the inflatable 
lap-belt system as installed. The special conditions are not an 
installation approval. Therefore, while the special conditions relate 
to each such system installed, the overall installation approval is 
separate, and must consider the combined effects of all such systems 
installed.
    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.

Applicability

    As discussed above, these special conditions are applicable to the 
Gulfstream Model GVII-G400 airplane. Should Gulfstream apply at a later 
date for a change to the type certificate to include another model 
incorporating the same novel or unusual design feature, these special 
conditions would apply to that model as well.

Conclusion

    This action affects only a certain novel or unusual design feature 
on one airplane model. It is not a rule of general applicability.

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, and 
44704.

The Special Conditions

0
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 Gulfstream Model GVII-G400 airplanes:
    1. The inflatable lap belt must deploy and provide protection under 
crash conditions where it is necessary to prevent serious head injury. 
The means of protection must take into consideration a range of stature 
from a two-year-old child to a 95th percentile male. The inflatable lap 
belt must provide a consistent approach to energy absorption throughout 
that range of occupants. In addition, the following situations must be 
considered:

[[Page 57073]]

    a. The seated occupant is holding an infant.
    b. The seated occupant is a child in a child-restraint device.
    c. The seated occupant is a pregnant woman.
    2. The inflatable lap belt must provide adequate protection for 
each occupant regardless of the number of occupants of the seat 
assembly, considering that unoccupied seats may have an active airbag 
system in the lap belt.
    3. The design must prevent the inflatable lap belt from being 
either incorrectly buckled or incorrectly installed such that the 
inflatable lap belt would not properly deploy. Alternatively, it must 
be shown that such deployment is not hazardous to the occupant and will 
provide the required injury protection.
    4. The inflatable lap belt system must not be susceptible to 
inadvertent deployment as a result of wear and tear, or inertial loads 
resulting from in-flight or ground maneuvers (including gusts and hard 
landings) likely to be experienced in service.
    5. Deployment of the inflatable lap belt must not injure the seated 
occupant, including injuries that would impede rapid evacuation. This 
assessment should include an occupant who is in the brace position when 
it deploys and an occupant whose belt is loosely fastened.
    6. It must be shown that inadvertent deployment of the inflatable 
lap belt, during the most critical part of the flight, will either meet 
the requirement of Sec.  25.1309(b) or not cause a hazard to the 
airplane or its occupants.
    7. The inflatable lap belt must not impede rapid evacuation of 
occupants 10 seconds after its deployment.
    8. The inflatable lap belt must function properly after loss of 
normal aircraft electrical power, and after a transverse separation of 
the fuselage at the most critical location. A separation at the 
location of the lap belt does not have to be considered.
    9. The inflatable lap belt must not release hazardous quantities of 
gas or particulate matter into the cabin.
    10. The inflatable lap belt installation must be protected from the 
effects of fire such that no hazard to occupants will result.
    11. There must be a means for a crewmember to verify the integrity 
of the inflatable lap belt activation system prior to each flight or it 
must be demonstrated to reliably operate between inspection intervals.
    12. The inflatable material must not have an average burn rate of 
greater than 2.5 inches/minute when tested using the horizontal 
flammability test as defined in 14 CFR part 25, appendix F, part I, 
paragraph (b)(5).
    13. The airbag system in the lap belt, once deployed, must not 
adversely affect the emergency lighting system (i.e., block proximity 
lights to the extent that the lights no longer meet their intended 
function).
    14. The inflatable lap belt system must be protected from lightning 
and high-intensity radiated fields (HIRF). The threats to the airplane 
specified in existing regulations regarding lightning, Sec.  25.1316, 
and HIRF, Sec.  25.1317, are adopted by reference for the purpose of 
measuring lightning and HIRF protection.

    Issued in Kansas City, Missouri, on July 8, 2024.
Patrick R. Mullen,
Manager, Technical Policy Branch, Policy and Standards Division, 
Aircraft Certification Service.
[FR Doc. 2024-15266 Filed 7-11-24; 8:45 am]
BILLING CODE 4910-13-P