DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0230; Project Identifier AD-2023-01064-A,Q,T]
RIN 2120-AA64

Airworthiness Directives; Various Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (SNPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA is revising a notice of proposed rulemaking (NPRM)
that applied to all airplanes with certain Pacific Scientific Company
rotary buckle assemblies (buckles) installed. This action revises the
NPRM by expanding the applicability and updating the referenced
material. As an option to the actions proposed by this SNPRM, this
SNPRM would allow removing the male side from the lap of the restraint
system assembly and installing a placard stating that use of the seat
is prohibited; use of that crewmember seat or passenger seat would then
be prohibited until the actions proposed by this SNPRM are accomplished
and the male side from the lap of the restraint system assembly is
reinstalled. The NPRM was prompted by a report of a manufacturing
defect in the screws used inside the buckle; this SNPRM is prompted by
the discovery that additional screws are affected by the unsafe
condition. The FAA is proposing this airworthiness directive (AD) to
address the unsafe condition on these products. Since these actions
would impose an additional burden over that in the NPRM, the FAA is
requesting comments on this SNPRM.

DATES: The FAA must receive comments on this SNPRM by March 28, 2025.

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 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.

AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2024-0230; or in person at Docket Operations between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD
docket contains this SNPRM, any comments received, and other
information. The street address for Docket Operations is listed above.

Material Incorporated by Reference:

For Parker Meggitt material identified in this AD, contact
Parker Meggitt Services, 1785 Voyager Avenue, Simi Valley, CA 93063;
phone: 877-666-0712; email: TechSupport@meggitt.com; website:
meggitt.com/services_and_support/customer_experience/update-on-
buckle-assembly-service-bulletins.

You may view this material at the FAA, Airworthiness
Products Section, Operational Safety Branch, 2200 South 216th Street,
Des Moines, WA. For information on the availability of this material at
the FAA, call 206-231-3195. It is also available at regulations.gov
under Docket No. FAA-2024-0230.

FOR FURTHER INFORMATION CONTACT: David Kim, Aviation Safety Engineer,
FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone: 562-627-5274;
email: David.Kim@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include "Docket No. FAA-2024-0230;
Project Identifier AD 2023-01064-A,Q,T" at the beginning of your
comments. The most helpful comments reference a specific portion of the
proposal, explain the reason for any recommended change, and include
supporting data. The FAA will consider all comments received by the
closing date and may again revise this proposal because of those
comments.

Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
regulations.gov, including any personal information you provide. The
agency will also post a report summarizing each substantive verbal
contact received about this proposed AD.

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 this SNPRM contain
commercial or financial information that is customarily treated as
private, that you actually treat as private, and that is relevant or
responsive to this SNPRM, 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 they will not be placed
in the public docket of this SNPRM. Submissions containing CBI should
be sent to David Kim, Aviation Safety Engineer, FAA, 3960 Paramount
Boulevard, Lakewood, CA 90712; phone: 562-627-5274; email:
David.Kim@faa.gov. Any commentary that the FAA receives that is not
specifically designated as CBI will be placed in the public docket for
this rulemaking.

Background

The FAA issued an NPRM to amend 14 CFR part 39 by adding an AD that
would apply to all airplanes with a Pacific Scientific Company buckle
part number (P/N) 1111475 (all dash numbers) or P/N 1111548-01
installed, if the buckle was manufactured between January 2012 and
September 2012 inclusive or has an unknown date of manufacture (DOM).
The NPRM published in the Federal Register on February 29, 2024 (89 FR
14783). The NPRM was prompted by a report of a 2012 manufacturing
defect in the screws used inside Pacific Scientific Company buckle P/N
1111475 (all dash numbers) and P/N 1111548-01. The screws used to
fasten the load plate to the body of the buckle were found to be
susceptible to hydrogen embrittlement due to improper baking during the
electroplating process. This condition leads the screwhead to separate
from the body of the screw when under load, which could result in the
buckle failing to restrain the occupant to the seat. This condition was
identified in screw Lots 348601-A and 348994-A, which were manufactured
between January 2012 and September 2012, and were the first two lots of
screws received by Pacific Scientific Company from a new supplier.

In the NPRM for airplanes with the identified buckle, the FAA
proposed to require inspecting each buckle screw for cracked, loose,
and missing screw heads and, depending on the results, replacing the
buckle or inspecting each screw to determine if any screw has a Torx
head. Depending on the results of that screw inspection, the NPRM
proposed to require reassembling the buckle (if necessary) and
reidentifying it with "INS. A" or replacing each Torx head screw with
a hex head screw, reassembling the buckle, and reidentifying the buckle
with "MOD. A." If a screw head broke off during disassembly, the NPRM
proposed to require replacing the buckle with an airworthy buckle.
Lastly, the NPRM proposed to prohibit installing an identified buckle
unless it was marked with "MOD. A" or "INS. A."

Actions Since the NPRM Was Issued

Since the FAA issued the NPRM, further review by the manufacturer
revealed that an additional lot of screws, Lot 358764-A, is also
affected by the same unsafe condition, which expands the DOM to April
2013 inclusive. These same part-numbered buckles may also be installed
in helicopters; the FAA published separate rulemaking, AD 2024-20-04,
Amendment 39-22863 (89 FR 85040, October 25, 2024) (AD 2024-20-04), to
address all helicopters with a Pacific Scientific Company buckle P/N
1111475 (all dash numbers) or P/N 1111548-01 having a DOM between
January 2012 and April 2013 inclusive, or an unknown DOM installed.

Parker Meggitt also revised Service Bulletin (SB) 1111475-25-001-
2023 and SB 1111548-25-001-2023, each Revision 001 and dated December
1, 2023 (SB 1111475-25-001-2023 Rev 001 and SB 1111548-25-001-2023 Rev
001), to SB 1111475-25-001-2023 and SB 1111548-25-001-2023, each
Revision 002 and dated April 1, 2024 (SB 1111475-25-001-2023 Rev 002
and SB 1111548-25-001-2023 Rev 002). SB 1111475-25-001-2023 Rev 002 and
SB 1111548-25-001-2023 Rev 002 specify the same procedures as SB
1111475-25-001-2023 Rev 001 and SB 1111548-25-001-2023 Rev 001, except
SB 1111475-25-001-2023 Rev 002 and SB 1111548-
25-001-2023 Rev 002 expand the applicability, update material and
tooling information, add and clarify certain Accomplishment
Instructions procedures, and update figures. A paragraph was added to
this proposed AD to provide credit if certain actions were accomplished
using SB 1111475-25-001-2023 Rev 001 and SB 1111548-25-001-2023 Rev 001.

The subject matter has been updated to reflect both the Air
Transport Assoction (ATA) and Joint Aircraft System Component (JASC) Codes.

Additionally, based on comments received on AD 2024-01-11
questioning if the AD was a rotorcraft or appliance AD, the FAA has
updated the project ID by adding the letters "A" and "T" to show
the project types for this proposed action as small airplane and
transport airplane in addition to the letter "Q" which signifies that
the product type is appliance.

The FAA is proposing this AD to address the unsafe condition on
these products.

Comments to the NPRM

The FAA received comments from nine commenters, including Air
Canada, Airbus Atlantic, Airbus SAS, American Airlines, Boeing, Collins
Aerospace, Delta Air Lines, Inc., Qatar Airways, and Southwest
Airlines. The following presents the comments received on the NPRM and
the FAA's response to each relevant comment.

Request for Clarification of the Applicability and Compliance Time

Air Canada, Collins Aerospace, and Qatar Airways requested
clarification regarding the applicability and proposed AD compliance
time. Commenters requested clarification regarding the proposed
inspections and if the AD would require inspecting all buckles despite
the DOM and if compliance with this AD would start with checking the
applicability or by inspecting the screws.

The FAA acknowledges these comments and infers concern that some
buckles may be repaired or replaced unnecessarily due to the date of
manufacture not being legible. Applicable part-numbered buckles with an
illegible or missing DOM, including those that may have never been
marked, are considered as having an unknown DOM for the purposes of
this proposed AD and would be required to comply with the proposed AD
requirements. Additionally, the proposed compliance time to accomplish
the inspections is within 12 months after the AD's effective date; only
if, as a result of the inspections, it is determined that a Torx head
screw is installed, is replacing each Torx head screw is required
before further flight. The DOM marking was added to buckle P/N 1111475
(all dash numbers) after the initial 2012 investigation while buckle P/
N 1111548-01 has always been marked with the DOM. Additionally, part
marking preservation and reidentification is the responsibility of
operators. As regards to if the applicability applies to all buckles,
the proposed AD has limited the applicibilty to certain buckles with a
DOM between January 2012 and April 2013 or if the DOM is not legible.

Requests Regarding the Magnet Used for the Magnet Test

Southwest Airlines stated that the magnetism strength of the magnet
is the representative physical quantity to determine if each screw has
a Torx head or hex head in the magnet test. Airbus Atlantic and
Southwest Airlines asked if Meggitt would provide more precise
information concerning the magnet, particularly its magnetism strength.
In addition, Airbus Atlantic requested that Meggitt specify the magnet
as a special tool within the applicable Service Bulletin and provide
the magnet to operators. Southwest Airlines commented that different
magnets could lead to erroneous results.

The FAA agrees that information regarding the magnet used for the
magnet test is beneficial for accomplishing the proposed inspections.
Since the NPRM was issued, SB 1111475-25-001-2023 Rev 001 has been
revised to Rev 002, to incorporate various changes, including the
addition of a website link to magnet P/N 5862K104 under the Material
Information, paragraph G.--Special Tooling. The website at this link
provides various magnet specification information. SB 1111475-25-001-
2023 Rev 002 also recommends certain magnet dimensions and explains
that a magnet that is strong enough to not slip off the buckle suffices
for the purposes of the magnet test. The FAA does not agree that the
use of different magnets could lead to erroneous results. If a magnet
is not strong enough, the procedures require that a different
inspection method is used. Regarding the request for Meggitt to provide
a magnet, the FAA does not have the authority to require a manufacturer
to send any tooling to an operator.

Request for Clarification for Using the Magnet

Airbus SAS requested additional guidance for using the magnet and
commented that during the magnet test to inspect for the type of screw,
the magnet must be in the hands of the person in charge of the
inspection at all times and not in proximity of any aircraft system.

The FAA agrees that a magnet should not be in proximity to any
aircraft system because magnets can cause damage to those systems. This
is reasonably understood to be standard maintenance practice. We
disagree with the statement that the magnet needs to always be in the
hands of the person performing the inspections. No changes are made to
this SNPRM as a result of this comment.

Request for Clarification of the Torque Values and Tools Required

Airbus SAS requested clarification of the tools and the specified
torque values required to complete the proposed actions. Airbus SAS
state that torque values and dimensions of the thin metal stock should
be provided.

The FAA agrees and SB 1111475-25-001-2023 Rev 001, as well as SB
1111548-25-001-2023 Rev 001, were revised to Rev 002, to incorporate
various changes, including the torque values, dimensions of the thin
metal stock, and magnet specifications. The FAA has updated this SNPRM
to reference revision 002 of the service bulletins.

Request for Clarification of the Disassembly Inspection

Airbus SAS states a concern with foreign object debris inside the
flight deck and proposes that any opening of the rotational buckle be
done outside of the aircraft, in-shop, or in any facility approved by
the suppler for this task.

The FAA disagrees that the task must be performed outside the
aircraft. These comments do not correct any proposed actions in the
NPRM, and it is reasonably understood to be standard maintenance
practices to maintain a clean workspace and proper tool containment to
prevent foreign object debris. No changes were made to this SNPRM.

Request for Clarification of the Visual Inspection

Airbus SAS commented that the risk of operator error in determining
the screw head type based on the method described in the SB can be
questioned due to limited visual access to the screws. Therefore, the
proposed AD should emphasize that in case of any doubt, the operator
shall confirm head types using either method #1 or method #3 (outside
aircraft only).

The FAA disagrees with this comment. The FAA concluded the
methods described in the SBs are appropriate for inspection of the
screws. No changes are made in this SNPRM.

Request for Clarification of the Applicability

American Airlines requested clarification regarding affected parts.
They asked whether the FAA thinks there is a concern that any buckle
with the applicable P/Ns may have had affected screws installed during
repair and therefore all buckles with the affected part numbers must be
inspected for screw installation and not DOM. American Airlines further
states that they repair their associated restraint assemblies and they
believe there may be a possibility of affected screws being installed
on belts manufactured before or after the DOM provided in the
applicability of the proposed AD and service information, though Parker
Meggitt communicated to American Airlines that none of the lots of
screws were shipped out individually as subcomponent spares orders and
that screw replacement is uncommon.

The FAA is not aware of any non-conforming screws installed in any
buckle assemblies other than those identified in the applicability of
this SNPRM. Accordingly, the FAA determines there is insufficient data
at this time to support further expanding the applicability above what
is proposed in this SNPRM. However, should additional information
reveal otherwise, the FAA may consider further rulemaking to expand the
applicability.

Request To Reidentify Buckles With "INS A"

American Airlines commented that in the NPRM, paragraph
2.(g)(2)(ii) does not offer the same options as paragraph
2.(g)(1)(ii)(A) and (B) to determine if there are Torx head screws and
reassemble the buckle if there are none. American Airlines requests
that instructions similar to paragraph 2.(g)(1)(ii)(A) and (B) be added
to paragraph 2.(g)(2)(ii) to allow the buckle to be reassembled and
reidentified with "INS. A" if no Torx head screws are discovered.
Parker Meggitt has communicated that SB 1111548-25-001-2023 will be
revised with instructions to reidentify the buckle with "INS. A" if
no Torx head screws are discovered.

The FAA agrees, SB 1111548-25-001-2023 was revised to include
additional steps to mark the buckle with "INS A" if the correct
screws were installed and the FAA has revised this SNPRM accordingly.

Request To Use Later-Approved Service Bulletins

American Airlines requests that the use of future revisions of the
service bulletin to comply with the proposed AD be allowed.

The FAA disagrees with the commenter's request. The FAA may not
refer to any document that does not yet exist in an AD. In general
terms, the FAA is required by Office of the Federal Register (OFR)
regulations for approval of materials incorporated by reference, as
specified in 1 CFR 51.1(f), to either publish the service document
contents as part of the actual AD language; or submit the service
document to the OFR for approval as referenced material, in which case
the FAA may only refer to such material in the text of an AD. The AD
may refer to the service document only if the OFR approved it for
incorporation by reference.

To allow operators to use later revisions of the referenced
document (issued after publication of the AD), the FAA must either
supersede the AD to reference specific later revisions, or operators
must request approval to use later revisions as an alternative method
of compliance (AMOC) under the provisions of paragraph (j) of this
proposed AD. No changes are made in this SNPRM.

Request To Clarify Spare Parts

American Airlines stated that there are no actions for spare parts
except that no affected parts should be installed after the effective
date of the proposed AD. American Airlines requests that the FAA
clarify if it was intentional that spare parts owned by the airline do
not require inspection by the effective date.

The FAA position is that spare buckles that have not been inspected
or repaired are considered unairworthy and must not be installed on
aircraft. Paragraph (h) of this proposed AD prohibits installing any
affected buckle unless it is inspected or modified and the 12 month
compliance time does not apply to spare parts. To the extent that spare
parts may not be available to replace parts that fail the inspection
requirements of this proposd AD, the FAA cannot base AD actions on
parts availablilty. While every effort is made to avoid grounding
aircraft, the FAA must address the unsafe condition. No changes are
made in this SNPRM.

Request To Change the Buckle Part Number

Airbus Atlantic, American Airlines, and Southwest Airlines
requested that the design approval holder change the P/N of the buckle
after completing the inspection or repair. The three commenters
requested that newly-manufactured buckles be marked with a new P/N,
"INS.A", or a secondary method of markingto easily distinguish
between potentially suspect buckles with Torx head and AD-compliant
parts that have stainless steel hex heads. The commenters are concerned
that lack of a differentiating P/N to suspect buckles will drive higher
compliance risk to the operators. In addition, the commenters request
changing to a more durable label on the P/N 1111475 series buckles
because the current label with the part number and DOM wears
prematurely, making the markings unreadable, and potentially increasing
the number of inspections.

The FAA acknowledges that the manufacturer introducing a new P/N
for newly-manufactured parts is ideal; however, the FAA cannot mandate
a company to change a P/N for an article. Applicable part-numbered
buckles with an illegible or missing DOM, including those that may have
never been marked, are considered as having an unknown DOM for the
purposes of this proposed AD and would be required to comply with the
proposed AD actions. The DOM marking was added to buckle P/N 1111475
(all dash numbers) after the initial 2012 investigation while buckle P/
N 1111548-01 has always been marked with the DOM. Additionally, part
marking preservation and reidentification is the responsibility of
operators. No changes are made in this SNPRM.

Request To Clarify the Proposed AD's Applicabilty

Boeing requested that the proposed AD's applicability include the
DOM. Boeing states that, as writtern, paragraph (g) of the proposed AD
could be confused to mean that all part-numbered buckles, regardless of
DOM, would require an in-depth inspection and repair, or replacement.

The FAA disagrees with this request because the applicability, as
written, clearly specifies that AD applies to airplanes with specific
part-numbered buckles with specific dates of manufacture or an unknown
DOM; this SNPRM contains no changes in regard to the comment.

Request To Clarify the Installation Prohibition

Boeing requested the applicability be changed to account for
buckles installed on airplanes manufactured after the date specified in
the applicability. Boeing requested that airplanes with an original
manufacture date after issuance of this proposed AD be exempt from the
proposed required actions but still be required to comply with
installation prohibition; Boeing stated that these airplanes would not
have the suspected buckles installed.

The FAA agrees, this proposed AD is for all airplanes with a
certain buckle installed. Aircraft manufactured after April 2013 might
not have the affected buckles installed, but an affected buckle might
have been installed after delivery. Therefore, all aircraft must comply
with the installation prohibition paragraph and not install an affected
buckle. No changes are made in this SNPRM.

Request to a Define Airworthy

Collins Aerospace requested a definition be added to the proposed
AD to define an "airworthy" buckle as a buckle with a known DOM to be
outside of DOM or repaired buckle that is within the DOM and includes
the "MOD. A" etching.

The FAA disagrees that a definition of airworthy is needed and made
no changes to this SNPRM in that regard.

Request to a Clarify Repairing a Buckle

Collins Aerospace and Delta Air Lines both requested that the FAA
specifiy where a buckle can be repaired and questioned whether the
buckle can be repaired instead of replaced. Delta Air Lines also
requested that the statement "except you are not required to return
any parts to Parker Meggitt" in paragraph (g)(1)(B) of the proposed AD
be similarly added to paragraph (g)(1)(i) and (g)(2)(i) of the proposed AD.

The FAA determination is that a repaired buckle is an airworthy
buckle. The Differences Between this Proposed AD and the Referenced
Material section also clarifies that this proposed AD would not require
returning the buckle to Parker Meggitt. Although the service
information requires returning buckles to Parker Meggitt, this proposed
AD would not have this requirement because the FAA does not have the
authority to direct operators to return defective components to the
manufacturer in this proposed AD. If an operator chooses to return a
damaged buckle to Parker Meggitt for repair as the proposed AD would
not prohibit an operator from doing so. Operators may also request
approval of any specific actions, including any specific corrective
actions, as an AMOC under the provisions of paragraph (j) of this
proposed AD. No changes in this regard are made in this SNPRM.

Request To Update the Number of Affected Buckles and Date of Manufacture

Collins Aerospace requested that the number of affected buckles be
updated in the Cost of Compliance and the DOM be changed in the
applicability because the DOM has increased from September 2012 to
April 2013.

The FAA agrees and has included an updated number for the affected
population and has changed DOM in the applicability from September 2012
to April 2013.

Request To Include Link to Service Bulletin in Required Actions

Collins Aerospace requested a link to the service bulletin be
provided in the required actions if a bulletin is referenced.

The FAA disagrees as links to referenced material are not provided
in the required actions. The ADDRESSES section, as well as paragraph
(l) of this AD, Material Incorporated by Reference, provide
availability information for the service bulletins, including the
website requested by Collins Aerospace. This material is also available
to interested parties through their normal course of business. No
changes are made in this SNPRM.

Request To Extend the Compliance Time

American Airlines, Delta Air Lines, and Qatar Airways requested an
extension of the compliance time ranging from 18-36 months due to spare
lead times, maintenance program intervals, and fleet size.

The FAA disagrees; the proposed 12-month compliance time was
determined after factoring an estimated 12-month processing time before
issuance of the final rule of this proposed AD and evaluating risks.
According to the manufacturer, an ample number of spare parts and
screws are in stock and will be available to modify the U.S. fleet
within the proposed compliance time. To the extent that spare parts may
not be available to replace parts that fail the inspection requirements
of this proposd AD, the FAA cannot base AD actions on parts
availablilty. While every effort is made to avoid grounding aircraft,
the FAA must address the unsafe condition. The FAA did not make any
changes to this SNPRM as a result of this comment.

Request To Replace the Buckle Instead of Complying With the AD

American Airlines, Delta Air Lines, and Southwest Airlines
requested an option to replace the buckle with an airworthy buckle
instead of inspecting and repairing it. Southwest Airlines requested
clarification of the FAA's position regarding deactivating non-
operational seats per their approved MEL (Minimum Equipment List).

The FAA agrees to clarify. It is understood that when an affected
buckle is replaced with an airworthy buckle the AD no longer applies
per the applicability paragraph. The FAA infers that Southwest Airlines
is requesting the FAA change the AD to allow deactivating and
placarding observer and flight attendant seats with affected parts as
"inoperative". The FAA agrees with the commenter's request and has
added an optional action for the proposed AD requirements. This AD
would allow, for a crewmember seat or passenger seat with a restraint
system with an affected buckle installed, removing the male side from
the lap of the restraint system assembly and fabricating and installing
a placard on the seat stating that use of the seat is prohibited. Use
of that crewmember seat or passenger seat would then be prohibited
until the actions proposed by this SNPRM are accomplished and the male
side from the lap of the restraint system assembly is reinstalled.

FAA's Determination

The FAA is proposing this AD after determining the unsafe condition
described previously is likely to exist or develop in other products of
the same type design. Certain changes described above expand the scope
of the NPRM. As a result, it is necessary to reopen the comment period
to provide additional opportunity for the public to comment on this SNPRM.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed SB 1111475-25-001-2023 Rev 002 for buckle P/N
1111475 and SB 1111548-25-001-2023 Rev 002 for buckle P/N 1111548-01.
This material specifies procedures for inspecting the buckle for any
missing or loose screw heads and, depending on the results, replacing
the buckle and sending the removed buckle to Parker Meggitt for repair
or replacement. If after that first inspection, all of the screw heads
are intact, this material specifies procedures for inspecting the
buckle for any Torx head screws (alloy steel) and, depending on the
results, allowing the buckle assembly to remain in-service temporarily,
replacing any Torx head screws (alloy steel) with new hex head screws
(stainless steel), and checking the functionality of the buckle. This
material also specifies procedures for removing a buckle from a
restraint system, installing a buckle on a restraint system, and
returning buckles to Parker
Meggitt. If the buckle passes the specified inspections or is modified
by replacing Torx head screws (alloy steel) with new hex head screws
(stainless steel) screws, this material specifies procedures for
reidentifying the back of the buckle.

The buckle may be included as a component of a different part-
numbered restraint system assembly. This material identifies known
affected restraint system assembly P/Ns.

This material is reasonably available because the interested
parties have access to it through their normal course of business or by
the means identified in the ADDRESSES section.

Proposed AD Requirements in This SNPRM

This proposed AD would require accomplishing the actions specified
in the material described previously, except as discussed under
"Differences Between this SNPRM and the Referenced Material."

Differences Between This SNPRM and the Referenced Material

The material proposed for incorporation by reference does not
specify any compliance times, whereas this proposed AD would require
accomplishing the required actions within twelve months. This proposed
AD would also prohibit installing an affected buckle on any airplane
unless the buckle includes "MOD A" or "INS A" on the buckle as of
the effective date of this AD.

The material proposed for incorporation by reference specifies
sending any damaged buckles to Parker Meggitt for repair or
replacement, and this proposed AD would not. Instead, this proposed AD
would require replacing the buckle with an airworthy buckle.

The material proposed for incorporation by reference allows buckles
with a Torx head (alloy steel) screw to remain in service temporarily
and be replaced at a time convenient to the operator, and this proposed
AD would not. If a buckle has any number of Torx head (alloy steel)
screws installed, this proposed AD would require replacing all four
screws with hex head screws before further flight.

If a screw head breaks off during disassembly of a buckle or if
reassembly of a buckle is not possible, the material proposed for
incorporation by reference specifies returning the buckle to Parker
Meggitt, whereas this proposed AD would not. If a screw head breaks off
during disassembly, this proposed AD would require replacing the buckle
with an airworthy buckle. If reassembly of a buckle is not possible,
then the buckle is not airworthy.

This proposed AD has the optional action, for a crewmember seat or
passenger seat with a restraint system with an affected buckle
installed, within 12 months after the effective date, of removing the
male side from the lap of the restraint system assembly and fabricating
and installing a placard on the seat stating that use of the seat is
prohibited. Use of that crewmember seat or passenger seat would then be
prohibited until the actions required by this proposed AD are
accomplished and the male side from the lap of the restraint system
assembly is reinstalled. The material proposed for incorporation by
reference does not include this optional action.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 21,313 buckles installed on restraint systems in aircraft
worldwide. The FAA has no way of knowing the number of airplanes of
U.S. Registry that may have a restraint system with an affected buckle
installed. The estimated costs on U.S. operators reflects the maximum
possible costs based on affected buckles installed on restraint systems
in aircraft worldwide. Labor rates are estimated at $85 per work-hour.
Based on these numbers, the FAA estimates the following costs to comply
with this proposed AD:

Estimated Costs

Estimated Costs for Optional Actions

The FAA estimates the following costs to do any necessary repairs
that would be required based on the results of the proposed inspection.
The agency has no way of determining the number of buckles that might
need this repair:

On-Condition Costs

The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, some of the costs of this
proposed AD may be covered under warranty, thereby reducing the cost
impact on affected operators.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I,
section 106, describes the authority of the FAA Administrator. Subtitle
VII: Aviation Programs describes in more detail the scope of the
Agency's authority.

The FAA is issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701: General requirements.
Under that section, Congress charges the FAA with promoting safe flight
of civil aircraft in air commerce by prescribing regulations for
practices, methods, and procedures the Administrator finds necessary
for safety in air commerce. This regulation is within the scope of that
authority because it addresses an unsafe condition that is likely to
exist or develop on products identified in this rulemaking action.

Regulatory Findings

The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would not
have a substantial direct effect on the States, on the relationship
between the national government and the States, or on the distribution
of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify this proposed regulation:

(1) Is not a "significant regulatory action" under Executive Order 12866,

(2) Would not affect intrastate aviation in Alaska, and

(3) Would not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

The Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive: