DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-1697; Project Identifier AD-2024-00252-T;
Amendment 39-22776; AD 2024-13-02]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
The Boeing Company Model 737-8, 737-9, and 737-8200 airplanes and Model
737-700, -800, and -900ER series airplanes. This AD was prompted by
multiple reports of passenger service unit (PSU) oxygen generators
shifting out of position within their associated PSU assemblies because
of a retention failure. This AD requires a general visual inspection of
the PSU oxygen generator installation to determine the configuration of
the thermal pads of the retention straps and applicable on-condition
actions. This AD also prohibits the installation of affected parts. The
FAA is issuing this AD to address the unsafe condition on these
products.

DATES: This AD is effective July 25, 2024.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of July 25,
2024.
The FAA must receive comments on this AD by August 26, 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-2024-1697; 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 final rule, any comments received, and other
information. The street address for Docket Operations is listed above.
Material Incorporated by Reference:
For Boeing material, 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; website
myboeingfleet.com.
You may view this material at the FAA, Airworthiness
Products Section, Operational Safety 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 at regulations.gov under
Docket No. FAA-2024-1697.

FOR FURTHER INFORMATION CONTACT: Nicole Tsang, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-
231-3959; email: Nicole.S.Tsang@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written data, views, or arguments
about this final rule. Send your comments to an address listed under
ADDRESSES. Include Docket No. FAA-2024-1697 and Project Identifier AD-
2024-00252-T at the beginning of your comments. The most helpful
comments reference a specific portion of the final rule, 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 final rule 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 final rule.

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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Nicole
Tsang, Aviation Safety Engineer, FAA, 2200 South 216th St. Des Moines,
WA 98198; phone: 206-231-3959; email: Nicole.S.Tsang@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 multiple reports of PSU oxygen generators
shifting out of position within their associated PSU assemblies because
of a retention failure. Boeing has investigated the condition and found
that the oxygen generator retention failures were caused by a failure
of the pressure-sensitive adhesive (PSA) material on certain generator
strap thermal pads. The oxygen generator is secured to the PSU assembly
by two retention straps, with either PSA or non-PSA thermal pads. For
all reported failures, the PSA thermal pad configurations were under
the retention straps. This condition, if not addressed, could result in
shifted PSU oxygen generators that might become non-functional, which
could result in an inability to provide supplemental oxygen to passengers during a
depressurization event. The FAA is issuing this AD to address the
unsafe condition on these products.

FAA's Determination

The FAA is issuing this AD because the agency has determined the
unsafe condition described previously is likely to exist or develop in
other products of the same type design.

Related Material Under 1 CFR Part 51

The FAA reviewed Boeing Special Attention Requirements Bulletin
737-35-1210 RB, dated June 17, 2024; and Boeing Special Attention
Requirements Bulletin 737-35-1211 RB, dated June 17, 2024. This
material specifies procedures for a general visual inspection of the
PSU oxygen generator installation to determine the configuration of the
thermal pads of the retention straps and applicable on-condition
actions for Group 1 and Group 2 airplanes as identified in this
material. On-condition actions include doing a general visual
inspection of the affected PSU oxygen generator to identify any
installation migration and expended oxygen, as applicable; replacing
affected PSU oxygen generators with new or serviceable PSU oxygen
generators; replacing PSA retention strap thermal pads with non-PSA
retention strap thermal pads; repositioning affected PSU oxygen
generators; and making sure affected PSU oxygen generator installation
migration is not found and oxygen has not been expended. These
documents are distinct since they apply to different airplane models.
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 ADDRESSES.

AD Requirements

This AD requires accomplishing the actions identified in Boeing
Special Attention Requirements Bulletin 737-35-1210 RB, dated June 17,
2024; or Boeing Special Attention Requirements Bulletin 737-35-1211 RB,
dated June 17, 2024, already described, except for any differences
identified as exceptions in the regulatory text of this AD. This AD
also prohibits the installation of affected parts for all airplanes
identified in paragraph (c) of this AD.
For information on the procedures and compliance times, see this
material at regulations.gov under Docket No. FAA-2024-1697.

Justification for Immediate Adoption and Determination of the Effective
Date

Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5
U.S.C. 551 et seq.) authorizes agencies to dispense with notice and
comment procedures for rules when the agency, for ``good cause,'' finds
that those procedures are ``impracticable, unnecessary, or contrary to
the public interest.'' Under this section, an agency, upon finding good
cause, may issue a final rule without providing notice and seeking
comment prior to issuance. Further, section 553(d) of the APA
authorizes agencies to make rules effective in less than thirty days,
upon a finding of good cause.
An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies forgoing notice and comment prior to adoption of this rule
because PSU oxygen generators might shift out of position within the
PSU assembly because of a retention failure and become non-functional,
which could result in an inability to provide supplemental oxygen to
passengers during a depressurization event. Accordingly, notice and
opportunity for prior public comment are impracticable and contrary to
the public interest pursuant to 5 U.S.C. 553(b)(3)(B).
The compliance time in this AD is shorter than the time necessary
for the public to comment and for publication of the final rule. In
addition, the FAA finds that good cause exists pursuant to 5 U.S.C.
553(d) for making this amendment effective in less than 30 days, for
the same reasons the FAA found good cause to forgo notice and comment.

Regulatory Flexibility Act

The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because the FAA has determined
that it has good cause to adopt this rule without notice and comment,
RFA analysis is not required.

Costs of Compliance

The FAA estimates that this AD affects 2,612 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:

Estimated Costs

The FAA estimates the following costs to do any necessary on-
condition actions that would be required based on the results of the
inspection. The FAA has no way of determining the number of aircraft
that might need these on-condition actions.

On-Condition Costs

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

This AD will not have federalism implications under Executive Order
13132. This AD will 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 that this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866, and
(2) Will not affect intrastate aviation in Alaska.

List of Subjects in 14 CFR Part 39

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

The Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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: