Special Conditions: The Boeing Company Model 737 Series Airplanes; Seats With Inertia Locking Devices, 39237-39239 [2019-17050]
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Federal Register / Vol. 84, No. 154 / Friday, August 9, 2019 / Proposed Rules
equivalent to that established by the
existing airworthiness standards.
Applicability
As discussed above, these special
conditions are applicable to Boeing
Model 777 series airplanes. Should
Boeing 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 one novel or
unusual design feature on one model
series of airplanes. 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, 44704.
khammond on DSKBBV9HB2PROD with PROPOSALS
The Proposed Special Conditions
Accordingly, the Federal Aviation
Administration (FAA) proposes the
following special conditions as part of
the type certification basis for Boeing
Model 777 series airplanes.
In addition to the requirements of
§ 25.562, passenger seats incorporating
an inertia locking device (ILD) must
meet the following:
1. Level of Protection Provided by
ILD—It must be demonstrated by test
that the seats and attachments, when
subject to the emergency-landing
dynamic conditions specified in
§ 25.562, and with one ILD not
deployed, do not experience structural
failure that could result in:
a. Separation of the seat from the
airplane floor.
b. Separation of any part of the seat
that could form a hazard to the seat
occupant or any other airplane
occupant.
c. Failure of the occupant restraint or
any other condition that could result in
the occupant separating from the seat.
2. Protection Provided Below and
Above the ILD Actuation Condition—If
step-change effects on occupant
protection exist for impacts below and
above that at which the ILD deploys,
tests must be performed to demonstrate
that the occupant is shown to be
protected at any condition at which the
ILD does or does not deploy, up to the
maximum severity pulse specified by
§ 25.562. Test conditions must take into
VerDate Sep<11>2014
15:57 Aug 08, 2019
Jkt 247001
account any necessary tolerances for
deployment.
3. Protection Over a Range of Crash
Pulse Vectors—The ILD must be shown
to function as intended for all test
vectors specified in § 25.562.
4. Protection During Secondary
Impacts—The ILD activation setting
must be demonstrated to maximize the
probability of the protection being
available when needed, considering a
secondary impact that is above the
severity at which the device is intended
to deploy up to the impact loading
required by § 25.562.
5. Protection of Occupants other than
50th Percentile—Protection of
occupants for a range of stature from a
two-year-old child to a ninety-five
percentile male must be shown.
6. Inadvertent Operation—It must be
shown that any inadvertent operation of
the ILD does not affect the performance
of the device during a subsequent
emergency landing.
7. Installation Protection—It must be
shown that the ILD installation is
protected from contamination and
interference from foreign objects.
8. Reliability—The performance of the
ILD must not be altered by the effects of
wear, manufacturing tolerances, aging/
drying of lubricants, and corrosion.
9. Maintenance and Functional
Checks—The design, installation, and
operation of the ILD must be such that
it is possible to functionally check the
device in place. Additionally, a
functional check method and a
maintenance check interval must be
included in the seat installer’s
instructions for continued airworthiness
(ICA) document.
10. Release Function—If a means
exists to release an inadvertently
activated ILD, the release means must
not introduce additional hidden failures
that would prevent the ILD from
functioning properly.
Issued in Des Moines, Washington, on
August 5, 2019.
Victor Wicklund,
Manager, Transport Standards Branch, Policy
and Innovation Division, Aircraft
Certification Service.
[FR Doc. 2019–17051 Filed 8–8–19; 8:45 am]
BILLING CODE 4910–13–P
PO 00000
Frm 00027
Fmt 4702
Sfmt 4702
39237
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA–2019–0540; Notice No. 25–
19–11–SC]
Special Conditions: The Boeing
Company Model 737 Series Airplanes;
Seats With Inertia Locking Devices
Federal Aviation
Administration (FAA), DOT.
ACTION: Notice of proposed special
conditions.
AGENCY:
This action proposes special
conditions for The Boeing Company
(Boeing) Model 737 series airplanes.
These airplanes 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 inertia locking
device (ILD) installed in passenger seats.
The applicable airworthiness
regulations do not contain adequate or
appropriate safety standards for this
design feature. These proposed 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: Send comments on or before
September 23, 2019.
ADDRESSES: Send comments identified
by Docket No. FAA–2019–0540 using
any of the following methods:
• Federal eRegulations Portal: Go to
https://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.
Privacy: The FAA will post all
comments it receives, without change,
to https://www.regulations.gov/,
including any personal information the
commenter provides. Using the search
function of the docket website, anyone
can find and read the electronic form of
all comments received into any FAA
docket, including the name of the
SUMMARY:
E:\FR\FM\09AUP1.SGM
09AUP1
39238
Federal Register / Vol. 84, No. 154 / Friday, August 9, 2019 / Proposed Rules
individual sending the comment (or
signing the comment for an association,
business, labor union, etc.). DOT’s
complete Privacy Act Statement can be
found in the Federal Register published
on April 11, 2000 (65 FR 19477–19478).
Docket: Background documents or
comments received may be read at
https://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 and Airframe
Safety Section, AIR–675, Transport
Standards Branch, Policy and
Innovation Division, Aircraft
Certification Service, Federal Aviation
Administration, 2200 South 216th
Street, Des Moines, Washington 98198;
telephone and fax 206–231–3209; email
shannon.lennon@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite 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.
We will consider all comments we
receive by the closing date for
comments. We may change these special
conditions based on the comments we
receive.
khammond on DSKBBV9HB2PROD with PROPOSALS
Background
On January 27, 2012, Boeing applied
for Type Certificate No. A16WE for
Model 737–8 airplanes. On September
19, 2018, Boeing applied for a change to
Type Certificate No. A16WE for seats
with inertia locking devices in Model
737 series airplanes. The Model 737
series airplane is a twin-engine,
transport-category airplane with a
maximum takeoff weight of 194,700
pounds and seating for 220 passengers.
Type Certification Basis
Under the provisions of title 14, Code
of Federal Regulations (14 CFR) 21.101,
Boeing must show that the Model 737
series airplanes, as changed, continue to
meet the applicable provisions of the
regulations listed in Type Certificate No.
A16WE, 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
VerDate Sep<11>2014
15:57 Aug 08, 2019
Jkt 247001
(i.e., 14 CFR part 25) do not contain
adequate or appropriate safety standards
for Boeing Model 737 series airplanes
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 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 § 21.101.
In addition to the applicable
airworthiness regulations and special
conditions, Boeing Model 737 series
airplanes must comply with the fuelvent and exhaust-emission requirements
of 14 CFR part 34, and the noisecertification 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
Boeing Model 737 series airplanes
will incorporate the following novel or
unusual design features:
Seats with inertia locking devices.
Discussion
Boeing has proposed to install, in
Model 737 series airplanes, Thompson
Aero Seating Ltd. passenger seats that
can be translated in the fore and aft
direction by an electrically powered
motor (actuator) that is attached to the
seat primary structure. Under typical
service-loading conditions, the motor
internal brake is able to translate the
seat and hold the seat in the translated
position. However, under the inertial
loads of emergency-landing loading
conditions specified in 14 CFR 25.562,
the motor internal brake may not be able
to maintain the seat in the required
position. The ILD is an ‘‘active’’ device
intended to control seat movement (i.e.,
a system that mechanically deploys
during an impact event) to lock the
gears of the motor assembly in place.
The ILD mechanism is activated by the
higher inertial load factors that could
occur during an emergency landing
event. Each seat place incorporates two
ILDs; one on either side of the seat pan.
Only one ILD is required to hold an
occupied seat in position during worst-
PO 00000
Frm 00028
Fmt 4702
Sfmt 4702
case dynamic loading specified in
§ 25.562.
The ILD will self-activate only in the
event of a predetermined airplane
loading condition such as that occurring
during crash or emergency landing, and
will prevent excessive seat forward
translation. A minimum level of
protection must be provided if the seatlocking device does not deploy.
The normal means of satisfying the
structural and occupant protection
requirements of § 25.562 result in a nonquantified, but nominally predictable,
progressive structural deformation or
reduction of injury severity for impact
conditions less than the maximum
specified by the rule. A seat using ILD
technology, however, may involve a
step change in protection for impacts
below and above that at which the ILD
activates and deploys to retain the seat
pan in place. This could result in
structural deformation or occupant
injury output being higher at an
intermediate impact condition than that
resulting from the maximum impact
condition. It is acceptable for such stepchange characteristics to exist, provided
the resulting output does not exceed the
maximum allowable criteria at any
condition at which the ILD does or does
not deploy, up to the maximum severity
pulse specified by the requirements.
The ideal triangular maximum
severity pulse is defined in Advisory
Circular (AC) 25.562–1B. For the
evaluation and testing of less-severe
pulses for purposes of assessing the
effectiveness of the ILD deployment
setting, a similar triangular pulse should
be used with acceleration, rise time, and
velocity change scaled accordingly. The
magnitude of the required pulse should
not deviate below the ideal pulse by
more than 0.5g until 1.33 t1 is reached,
where t1 represents the time interval
between 0 and t1 on the referenced
pulse shape as shown in AC 25.562–1B.
This is an acceptable method of
compliance to the test requirements of
the special conditions.
Proposed conditions 1 through 5
address ensuring that the ILD activates
when intended in order to provide the
necessary protection of occupants. This
includes protection of a range of
occupants under various accident
conditions. Proposed conditions 6
through 10 address maintenance and
reliability of the ILD, including any
outside influences on the mechanism, to
ensure it functions as intended.
The proposed 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.
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Federal Register / Vol. 84, No. 154 / Friday, August 9, 2019 / Proposed Rules
Applicability
As discussed above, these special
conditions are applicable to Boeing
Model 737 series airplanes. Should
Boeing 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 one novel or
unusual design feature on one model
series of airplanes. 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:
khammond on DSKBBV9HB2PROD with PROPOSALS
Authority: 49 U.S.C. 106(f), 106(g), 40113,
44701, 44702, 44704.
The Proposed Special Conditions
Accordingly, the Federal Aviation
Administration (FAA) proposes the
following special conditions as part of
the type certification basis for Boeing
Model 737 series airplanes.
In addition to the requirements of
§ 25.562, passenger seats incorporating
an inertia locking device (ILD) must
meet the following:
1. Level of Protection Provided by
ILD—It must be demonstrated by test
that the seats and attachments, when
subject to the emergency-landing
dynamic conditions specified in
§ 25.562, and with one ILD not
deployed, do not experience structural
failure that could result in:
a. Separation of the seat from the
airplane floor.
b. Separation of any part of the seat
that could form a hazard to the seat
occupant or any other airplane
occupant.
c. Failure of the occupant restraint or
any other condition that could result in
the occupant separating from the seat.
2. Protection Provided Below and
Above the ILD Actuation Condition—If
step-change effects on occupant
protection exist for impacts below and
above that at which the ILD deploys,
tests must be performed to demonstrate
that the occupant is shown to be
protected at any condition at which the
ILD does or does not deploy, up to the
maximum severity pulse specified by
§ 25.562. Test conditions must take into
account any necessary tolerances for
deployment.
3. Protection Over a Range of Crash
Pulse Vectors—The ILD must be shown
VerDate Sep<11>2014
15:57 Aug 08, 2019
Jkt 247001
to function as intended for all test
vectors specified in § 25.562.
4. Protection During Secondary
Impacts—The ILD activation setting
must be demonstrated to maximize the
probability of the protection being
available when needed, considering a
secondary impact that is above the
severity at which the device is intended
to deploy up to the impact loading
required by § 25.562.
5. Protection of Occupants other than
50th Percentile—Protection of
occupants for a range of stature from a
two-year-old child to a ninety-five
percentile male must be shown.
6. Inadvertent Operation—It must be
shown that any inadvertent operation of
the ILD does not affect the performance
of the device during a subsequent
emergency landing.
7. Installation Protection—It must be
shown that the ILD installation is
protected from contamination and
interference from foreign objects.
8. Reliability—The performance of the
ILD must not be altered by the effects of
wear, manufacturing tolerances, aging/
drying of lubricants, and corrosion.
9. Maintenance and Functional
Checks—The design, installation and
operation of the ILD must be such that
it is possible to functionally check the
device in place. Additionally, a
functional check method and a
maintenance check interval must be
included in the seat installer’s
instructions for continued airworthiness
(ICA) document.
10. Release Function—If a means
exists to release an inadvertently
activated ILD, the release means must
not introduce additional hidden failures
that would prevent the ILD from
functioning properly.
Issued in Des Moines, Washington, on
August 5, 2019.
Victor Wicklund,
Manager, Transport Standards Branch, Policy
and Innovation Division, Aircraft
Certification Service.
[FR Doc. 2019–17050 Filed 8–8–19; 8:45 am]
BILLING CODE 4910–13–P
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA–2019–0583; Product
Identifier 2019–NM–063–AD]
RIN 2120–AA64
Airworthiness Directives; The Boeing
Company Airplanes
Federal Aviation
Administration (FAA), DOT.
AGENCY:
PO 00000
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39239
Notice of proposed rulemaking
(NPRM).
ACTION:
The FAA proposes to adopt a
new airworthiness directive (AD) for
certain The Boeing Company Model
787–8 airplanes. This proposed AD was
prompted by a report of an escapement
from the wing spar terminal fitting
supplier indicating that the engineering
requirements provided by Boeing for
controlling machine mismatch were
incorrect for part faying surfaces, which
can result in a reduced fatigue
capability at the interface of the side of
body (SOB) rib. This proposed AD
would require repetitive inspections for
fatigue cracking and applicable oncondition actions for the SOB rib webs
where fastener locations attach the
terminal fittings. The FAA is proposing
this AD to address the unsafe condition
on these products.
DATES: The FAA must receive comments
on this proposed AD by September 23,
2019.
ADDRESSES: You may send comments,
using the procedures found in 14 CFR
11.43 and 11.45, by any of the following
methods:
• Federal eRulemaking Portal: Go to
https://www.regulations.gov. Follow the
instructions for submitting comments.
• Fax: 202–493–2251.
• Mail: U.S. Department of
Transportation, Docket Operations, M–
30, West Building Ground Floor, Room
W12–140, 1200 New Jersey Avenue SE,
Washington, DC 20590.
• Hand Delivery: Deliver to Mail
address above between 9 a.m. and 5
p.m., Monday through Friday, except
Federal holidays.
For service information identified in
this NPRM, contact Boeing Commercial
Airplanes, Attention: Contractual & Data
Services (C&DS), 2600 Westminster
Blvd., MC 110–SK57, Seal Beach, CA
90740–5600; telephone 562–797–1717;
internet https://
www.myboeingfleet.com. You may view
this referenced service information at
the FAA, Transport Standards Branch,
2200 South 216th St., Des Moines, WA.
For information on the availability of
this material at the FAA, call 206–231–
3195. It is also available on the internet
at https://www.regulations.gov by
searching for and locating Docket No.
FAA–2019–0583.
SUMMARY:
Examining the AD Docket
You may examine the AD docket on
the internet at https://
www.regulations.gov by searching for
and locating Docket No. FAA–2019–
0583; or in person at Docket Operations
between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.
E:\FR\FM\09AUP1.SGM
09AUP1
]]>Agencies
[Federal Register Volume 84, Number 154 (Friday, August 9, 2019)]
[Proposed Rules]
[Pages 39237-39239]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-17050]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2019-0540; Notice No. 25-19-11-SC]
Special Conditions: The Boeing Company Model 737 Series
Airplanes; Seats With Inertia Locking Devices
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
-----------------------------------------------------------------------
SUMMARY: This action proposes special conditions for The Boeing Company
(Boeing) Model 737 series airplanes. These airplanes 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 inertia locking device (ILD)
installed in passenger seats. The applicable airworthiness regulations
do not contain adequate or appropriate safety standards for this design
feature. These proposed 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: Send comments on or before September 23, 2019.
ADDRESSES: Send comments identified by Docket No. FAA-2019-0540 using
any of the following methods:
Federal eRegulations Portal: Go to https://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.
Privacy: The FAA will post all comments it receives, without
change, to https://www.regulations.gov/, including any personal
information the commenter provides. Using the search function of the
docket website, anyone can find and read the electronic form of all
comments received into any FAA docket, including the name of the
[[Page 39238]]
individual sending the comment (or signing the comment for an
association, business, labor union, etc.). DOT's complete Privacy Act
Statement can be found in the Federal Register published on April 11,
2000 (65 FR 19477-19478).
Docket: Background documents or comments received may be read at
https://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 and Airframe
Safety Section, AIR-675, Transport Standards Branch, Policy and
Innovation Division, Aircraft Certification Service, Federal Aviation
Administration, 2200 South 216th Street, Des Moines, Washington 98198;
telephone and fax 206-231-3209; email [email protected].
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite 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.
We will consider all comments we receive by the closing date for
comments. We may change these special conditions based on the comments
we receive.
Background
On January 27, 2012, Boeing applied for Type Certificate No. A16WE
for Model 737-8 airplanes. On September 19, 2018, Boeing applied for a
change to Type Certificate No. A16WE for seats with inertia locking
devices in Model 737 series airplanes. The Model 737 series airplane is
a twin-engine, transport-category airplane with a maximum takeoff
weight of 194,700 pounds and seating for 220 passengers.
Type Certification Basis
Under the provisions of title 14, Code of Federal Regulations (14
CFR) 21.101, Boeing must show that the Model 737 series airplanes, as
changed, continue to meet the applicable provisions of the regulations
listed in Type Certificate No. A16WE, 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 (i.e., 14 CFR part 25) do not contain adequate or
appropriate safety standards for Boeing Model 737 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 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, Boeing Model 737 series airplanes must comply with the
fuel-vent and 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 the type
certification basis under Sec. 21.101.
Novel or Unusual Design Features
Boeing Model 737 series airplanes will incorporate the following
novel or unusual design features:
Seats with inertia locking devices.
Discussion
Boeing has proposed to install, in Model 737 series airplanes,
Thompson Aero Seating Ltd. passenger seats that can be translated in
the fore and aft direction by an electrically powered motor (actuator)
that is attached to the seat primary structure. Under typical service-
loading conditions, the motor internal brake is able to translate the
seat and hold the seat in the translated position. However, under the
inertial loads of emergency-landing loading conditions specified in 14
CFR 25.562, the motor internal brake may not be able to maintain the
seat in the required position. The ILD is an ``active'' device intended
to control seat movement (i.e., a system that mechanically deploys
during an impact event) to lock the gears of the motor assembly in
place. The ILD mechanism is activated by the higher inertial load
factors that could occur during an emergency landing event. Each seat
place incorporates two ILDs; one on either side of the seat pan. Only
one ILD is required to hold an occupied seat in position during worst-
case dynamic loading specified in Sec. 25.562.
The ILD will self-activate only in the event of a predetermined
airplane loading condition such as that occurring during crash or
emergency landing, and will prevent excessive seat forward translation.
A minimum level of protection must be provided if the seat-locking
device does not deploy.
The normal means of satisfying the structural and occupant
protection requirements of Sec. 25.562 result in a non-quantified, but
nominally predictable, progressive structural deformation or reduction
of injury severity for impact conditions less than the maximum
specified by the rule. A seat using ILD technology, however, may
involve a step change in protection for impacts below and above that at
which the ILD activates and deploys to retain the seat pan in place.
This could result in structural deformation or occupant injury output
being higher at an intermediate impact condition than that resulting
from the maximum impact condition. It is acceptable for such step-
change characteristics to exist, provided the resulting output does not
exceed the maximum allowable criteria at any condition at which the ILD
does or does not deploy, up to the maximum severity pulse specified by
the requirements.
The ideal triangular maximum severity pulse is defined in Advisory
Circular (AC) 25.562-1B. For the evaluation and testing of less-severe
pulses for purposes of assessing the effectiveness of the ILD
deployment setting, a similar triangular pulse should be used with
acceleration, rise time, and velocity change scaled accordingly. The
magnitude of the required pulse should not deviate below the ideal
pulse by more than 0.5g until 1.33 t1 is reached, where
t1 represents the time interval between 0 and t1
on the referenced pulse shape as shown in AC 25.562-1B. This is an
acceptable method of compliance to the test requirements of the special
conditions.
Proposed conditions 1 through 5 address ensuring that the ILD
activates when intended in order to provide the necessary protection of
occupants. This includes protection of a range of occupants under
various accident conditions. Proposed conditions 6 through 10 address
maintenance and reliability of the ILD, including any outside
influences on the mechanism, to ensure it functions as intended.
The proposed 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.
[[Page 39239]]
Applicability
As discussed above, these special conditions are applicable to
Boeing Model 737 series airplanes. Should Boeing 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 one novel or unusual design feature on one
model series of airplanes. 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,
44704.
The Proposed Special Conditions
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for Boeing Model 737 series airplanes.
In addition to the requirements of Sec. 25.562, passenger seats
incorporating an inertia locking device (ILD) must meet the following:
1. Level of Protection Provided by ILD--It must be demonstrated by
test that the seats and attachments, when subject to the emergency-
landing dynamic conditions specified in Sec. 25.562, and with one ILD
not deployed, do not experience structural failure that could result
in:
a. Separation of the seat from the airplane floor.
b. Separation of any part of the seat that could form a hazard to
the seat occupant or any other airplane occupant.
c. Failure of the occupant restraint or any other condition that
could result in the occupant separating from the seat.
2. Protection Provided Below and Above the ILD Actuation
Condition--If step-change effects on occupant protection exist for
impacts below and above that at which the ILD deploys, tests must be
performed to demonstrate that the occupant is shown to be protected at
any condition at which the ILD does or does not deploy, up to the
maximum severity pulse specified by Sec. 25.562. Test conditions must
take into account any necessary tolerances for deployment.
3. Protection Over a Range of Crash Pulse Vectors--The ILD must be
shown to function as intended for all test vectors specified in Sec.
25.562.
4. Protection During Secondary Impacts--The ILD activation setting
must be demonstrated to maximize the probability of the protection
being available when needed, considering a secondary impact that is
above the severity at which the device is intended to deploy up to the
impact loading required by Sec. 25.562.
5. Protection of Occupants other than 50th Percentile--Protection
of occupants for a range of stature from a two-year-old child to a
ninety-five percentile male must be shown.
6. Inadvertent Operation--It must be shown that any inadvertent
operation of the ILD does not affect the performance of the device
during a subsequent emergency landing.
7. Installation Protection--It must be shown that the ILD
installation is protected from contamination and interference from
foreign objects.
8. Reliability--The performance of the ILD must not be altered by
the effects of wear, manufacturing tolerances, aging/drying of
lubricants, and corrosion.
9. Maintenance and Functional Checks--The design, installation and
operation of the ILD must be such that it is possible to functionally
check the device in place. Additionally, a functional check method and
a maintenance check interval must be included in the seat installer's
instructions for continued airworthiness (ICA) document.
10. Release Function--If a means exists to release an inadvertently
activated ILD, the release means must not introduce additional hidden
failures that would prevent the ILD from functioning properly.
Issued in Des Moines, Washington, on August 5, 2019.
Victor Wicklund,
Manager, Transport Standards Branch, Policy and Innovation Division,
Aircraft Certification Service.
[FR Doc. 2019-17050 Filed 8-8-19; 8:45 am]
BILLING CODE 4910-13-P
