DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

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

Airworthiness Directives; Various Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for all airplanes with certain Pacific Scientific Company rotary buckle
assemblies (buckles) installed. This AD was prompted by a report of a
manufacturing defect in the screws used inside the buckle. This
proposed AD would require inspecting the buckle screws, and depending
on the results, reidentifying the buckle, replacing the screws and
reidentifying the buckle, or replacing the buckle. This proposed AD
would also prohibit installing certain buckles. 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 April 15,
2024.

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 NPRM, any comments received, and other
information. The street address for Docket Operations is listed above.
Material Incorporated by Reference:
For service information identified in this NPRM, 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 service information 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 by searching for and locating 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 ADDRESSES. Include ``Docket No. FAA-2024-0230; Project Identifier
AD-2023-01064-Q'' 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 amend
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 NPRM.

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 NPRM 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 NPRM, 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 NPRM. 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 has received a report of a manufacturing defect in the
screws used inside Pacific Scientific Company buckle part number (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 issue was
originally identified from a suspected lot of screws, Lot 348994-A.
Since then, a buckle failed in an accident, calling into question Lot
348601-A. Lots 348601-A and 348994-A were the first two lots of screws
received by Pacific Scientific Company from a new supplier and are the
only suspected lots. The suspected buckles were manufactured between
January 2012 and September 2012. The FAA is proposing this AD to
address the unsafe condition on these products.
The rotary buckle may be included as a component of a different
part-numbered restraint system assembly. Table 1 of Parker Meggitt
Service Bulletin (SB) 1111475-25-001-2023, Revision 001, dated December
1, 2023, and Parker Meggitt SB 1111548-25-001-2023, Revision 001, dated
December 1, 2023 (SB 1111475-25-001-2023 Rev 001 and SB 1111548-25-001-
2023 Rev 001), includes a list of these restraint system assembly P/Ns.
This proposed AD would apply to all airplanes with a Pacific
Scientific Company buckle P/N 1111475 (all dash numbers) or P/N
1111548-01 installed, if the buckle was manufactured between January
2012 and September 2012, or if the date of manufacture of the buckle is
unknown. These same part-numbered buckles may also be installed in
helicopters; however, the FAA determined that a shorter compliance time
to accomplish the required actions is necessary for buckles installed
in helicopters. Accordingly, the FAA issued AD 2024-01-11, Amendment
39-22662 (89 FR 6008, January 31, 2024), to address this unsafe
condition on all helicopters with a Pacific Scientific Company buckle
P/N 1111475 (all dash numbers) or P/N 1111548-01 installed.

FAA's Determination

The FAA is issuing this NPRM after determining that the unsafe
condition described previously is likely to exist or develop on other
airplanes with a restraint system with a buckle as part of their type
design.

Related Service Information Under 1 CFR Part 51

The FAA reviewed SB 1111475-25-001-2023 Rev 001 for buckle P/N
1111475 and SB 1111548-25-001-2023 Rev 001 for buckle P/N 1111548-01.
This service information 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 service information 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 service information 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 service information specifies procedures for
reidentifying the back of the buckle. This service information also
identifies known affected restraint systems.
This service information is reasonably available because the
interested parties have access to it through their normal course of
business or by the means identified in ADDRESSES.

Proposed AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified
in the service information already described, except as discussed under
``Differences Between this Proposed AD and the Service Information.''

Differences Between This Proposed AD and the Service Information

The service information 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.
The service information 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 service information allows buckles with a Torx head (alloy
steel) screw to remain in service temporarily and 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 service information
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.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 11,714 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

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: