[4910-13-P]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-1697; Project Identifier AD-2024-00252-T; Amendment 3922776; 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 [INSERT DATE 15 DAYS AFTER DATE OF
PUBLICATION IN THE FEDERAL REGISTER].
The Director of the Federal Register approved the incorporation by reference of
certain publications listed in this AD as of [INSERT DATE 15 DAYS AFTER DATE OF
PUBLICATION IN THE FEDERAL REGISTER].
The FAA must receive comments on this AD by [INSERT DATE 45 DAYS
AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].

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. FAA2024-1697; 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 nonfunctional, 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
Action

Labor cost

Inspection to determine
1 work-hour X
thermal pad configuration of $85 per hour =
the PSU oxygen generator
$85

Parts
cost

Cost per
product

Cost on U.S.
operators

$0

$85

$222,020

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
Action

Labor cost

Parts cost

Cost per product

Inspection to identify any
expended oxygen and
installation migration, as
applicable

1 work-hour X $85 per
hour = $85

$0

$85

Replacement of PSU
oxygen generator

1 work-hour X $85 per
hour = $85

Up to $1,374

Up to $1,459

Replacement of PSA
retention strap thermal
pad (each PSU oxygen
generator has 2 pads)

1 work-hour X $85 per
hour = $85, per pad

$68, per pad

$153, per pad

Repositioning of PSU
oxygen generator

1 work-hour X $85 per
hour = $85

$0

$85

Making sure PSU oxygen
generator installation
1 work-hour X $85 per
migration is not found
hour = $85
and oxygen is not
expended

$0

$85

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.
§ 39.13 [Amended]
2. The FAA amends § 39.13 by adding the following new airworthiness directive:

2024-13-02 The Boeing Company: Amendment 39-22776; Docket No. FAA-20241697; Project Identifier AD-2024-00252-T.
(a) Effective Date
This airworthiness directive (AD) is effective [INSERT DATE 15 DAYS AFTER
DATE OF PUBLICATION IN THE FEDERAL REGISTER].
(b) Affected ADs
None.
(c) Applicability
This AD applies to all The Boeing Company Model 737-8, 737-9, and 737-8200
airplanes and Model 737-700, -800, and -900ER series airplanes, certificated in any
category.
(d) Subject
Air Transport Association (ATA) of America Code 35, Oxygen.
(e) Unsafe Condition
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. The FAA is issuing this AD to address PSU oxygen
generators that might shift out of position within the PSU assembly and become nonfunctional. The unsafe condition, if not addressed, could result in an inability to provide
supplemental oxygen to passengers during a depressurization event.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Required Actions
(1) For Model 737-8, 737-9, and 737-8200 airplanes as identified in Boeing
Special Attention Requirements Bulletin 737-35-1210 RB, dated June 17, 2024: Except
as specified by paragraph (h) of this AD, at the applicable times specified in the

“Compliance” paragraph of Boeing Special Attention Requirements Bulletin 737-351210 RB, dated June 17, 2024, do all applicable actions identified in, and in accordance
with, the Accomplishment Instructions of Boeing Special Attention Requirements
Bulletin 737-35-1210 RB, dated June 17, 2024.
Note 1 to paragraph (g)(1): Guidance for accomplishing the actions required by
this AD can be found in Boeing Special Attention Service Bulletin 737-35-1210, dated
June 17, 2024, which is referred to in Boeing Special Attention Requirements Bulletin
737-35-1210 RB, dated June 17, 2024.
(2) For Model 737-700, -800, and -900ER series airplanes as identified in Boeing
Special Attention Requirements Bulletin 737-35-1211 RB, dated June 17, 2024: Except
as specified by paragraph (h) of this AD, at the applicable times specified in the
“Compliance” paragraph of Boeing Special Attention Requirements Bulletin
737-35-1211 RB, dated June 17, 2024, do all applicable actions identified in, and in
accordance with, the Accomplishment Instructions of Boeing Special Attention
Requirements Bulletin 737-35-1211 RB, dated June 17, 2024.
Note 2 to paragraph (g)(2): Guidance for accomplishing the actions required by
this AD can be found in Boeing Special Attention Service Bulletin 737-35-1211, dated
June 17, 2024, which is referred to in Boeing Special Attention Requirements Bulletin
737-35-1211 RB, dated June 17, 2024.
(h) Exceptions to Service Information Specifications
(1) Where the Compliance Time columns of the tables in the “Compliance”
paragraph of Boeing Special Attention Requirements Bulletin 737-35-1210 RB, dated
June 17, 2024, refer to the original issue date of Requirements Bulletin 737-35-1210 RB,
this AD requires using the effective date of this AD.
(2) Where the Compliance Time columns of the tables in the “Compliance”
paragraph of Boeing Special Attention Requirements Bulletin 737-35-1211 RB, dated

June 17, 2024, refer to the original issue date of Requirements Bulletin 737-35-1211 RB,
this AD requires using the effective date of this AD.
(i) Parts Installation Prohibition
As of the effective date of the AD, no person may install a pressure-sensitive
adhesive (PSA) thermal pad, part number 53010 or 73667, under the PSU oxygen
generator retention strap, on any airplane.
(j) Alternative Methods of Compliance (AMOCs)
(1) The Manager, AIR-520, Continued Operational Safety Branch, FAA, has the
authority to approve AMOCs for this AD, if requested using the procedures found in
14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal
inspector or responsible Flight Standards Office, as appropriate. If sending information
directly to the manager of the certification office, send it to the attention of the person
identified in paragraph (k)(1) of this AD. Information may be emailed to:
AMOC@faa.gov.
(2) Before using any approved AMOC, notify your appropriate principal
inspector, or lacking a principal inspector, the manager of the responsible Flight
Standards Office.
(3) An AMOC that provides an acceptable level of safety may be used for any
repair, modification, or alteration required by this AD if it is approved by The Boeing
Company Organization Designation Authorization (ODA) that has been authorized by the
Manager, AIR-520, Continued Operational Safety Branch, FAA, to make those findings.
To be approved, the repair method, modification deviation, or alteration deviation must
meet the certification basis of the airplane, and the approval must specifically refer to this
AD.

(k) Related Information
(1) For more information about this AD, 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.
(2) Boeing material identified in this AD that is not incorporated by reference is
available at the address specified in paragraph (l)(3) of this AD.
(l) Material Incorporated by Reference
(1) The Director of the Federal Register approved the incorporation by reference
(IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR
part 51.
(2) You must use this material as applicable to do the actions required by this AD,
unless the AD specifies otherwise.
(i) Boeing Special Attention Requirements Bulletin 737-35-1210 RB, dated
June 17, 2024.
(ii) Boeing Special Attention Requirements Bulletin 737-35-1211 RB, dated
June 17, 2024.
(3) 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.
(4) 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.
(5) You may view this material at the National Archives and Records
Administration (NARA). For information on the availability of this material at NARA,
visit www.archives.gov/federal-register/cfr/ibr-locations or email
fr.inspection@nara.gov.

Issued on June 20, 2024.

Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2024-15229 Filed: 7/8/2024 11:15 am; Publication Date: 7/10/2024]