Rule2024-15266
Special Conditions: Gulfstream Aerospace Corporation (Gulfstream) Model GVII-G400 Airplane; Seats With Inflatable Lapbelts
Primary source
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Published
July 12, 2024
Effective
July 12, 2024
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
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.
Full Text
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<title>Federal Register, Volume 89 Issue 134 (Friday, July 12, 2024)</title>
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[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 [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[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:
<bullet> Federal eRegulations Portal: Go to <a href="http://www.regulations.gov">www.regulations.gov</a> and
follow the online instructions for sending your comments
electronically.
<bullet> 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.
<bullet> 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.
<bullet> Fax: Fax comments to Docket Operations at 202-493-2251.
Docket: Background documents or comments received may be read at
<a href="http://www.regulations.gov">www.regulations.gov</a> 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 <a href="/cdn-cgi/l/email-protection#05687c77642b6f2b6e70666e456364642b626a73"><span class="__cf_email__" data-cfemail="64091d16054a0e4a0f11070f240205054a030b12">[email protected]</span></a>.
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 <a href="http://www.regulations.gov">www.regulations.gov</a>,
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<SUP>-9</SUP> 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
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