84264 Federal Register / Vol. 89, No. 204 / Tuesday, October 22, 2024 / Rules and Regulations 

correct operation of the safety belts, possibly 

resulting in injuries to seat occupants. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Requirements 

Except as specified in paragraph (h) of this 

AD: Comply with all required actions and 

compliance times specified in, and in 

accordance with, European Union Aviation 

Safety Agency (EASA) AD 2024–0051, dated 

February 23, 2024 (EASA AD 2024–0051). 

(h) Exceptions to EASA AD 2024–0051 

(1) Where EASA AD 2024–0051 refers to its 

effective date, this AD requires using the 

effective date of this AD. 

(2) Where paragraph (2) of EASA AD 2024– 

0051 specifies ‘‘if, during the inspection 

required by paragraph (1) of this AD, 

discrepancies are detected, as defined in the 

ASB, before next flight, contact Deutsche 

Aircraft GmbH and Collins Aerospace for 

approved instructions and accomplish those 

instructions accordingly,’’ this AD requires 

replacing that text with ‘‘if, during the 

inspection as required by paragraph (1) of 

this AD, any discrepancy is detected, the 

discrepancy must be repaired before further 

flight using a method approved by the 

Manager, International Validation Branch, 

FAA; or EASA; or Deutsche Aircraft GmbH’s 

EASA Design Organization Approval (DOA). 

If approved by the DOA, the approval must 

include the DOA-authorized signature.’’ 

(3) This AD does not adopt the ‘‘Remarks’’ 

section of EASA AD 2024–0051. 

(i) No Reporting or Return of Parts 

Requirement 

Although the service information 

referenced in EASA AD 2024–0051 specifies 

to submit certain information and send 

removed parts to the manufacturer, this AD 

does not include that requirement. 

(j) Additional AD Provisions 

The following provisions also apply to this 

AD: 

(1) Alternative Methods of Compliance 

(AMOCs): The Manager, International 

Validation 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 International Validation 

Branch, mail it to the address identified in 

paragraph (k) of this AD. Information may be 

emailed to: AMOC@faa.gov. Before using any 

approved AMOC, notify your appropriate 

principal inspector, or lacking a principal 

inspector, the manager of the responsible 

Flight Standards Office. 

(2) Contacting the Manufacturer: For any 

requirement in this AD to obtain instructions 

from a manufacturer, the instructions must 

be accomplished using a method approved 

by the Manager, International Validation 

Branch, FAA; or EASA; or Deutsche Aircraft 

GmbH’s EASA DOA. If approved by the 

DOA, the approval must include the DOAauthorized signature. 

(k) Additional Information 

For more information about this AD, 

contact Todd Thompson, Aviation Safety 

Engineer, FAA, 1600 Stewart Avenue, Suite 

410, Westbury, NY 11590; telephone 206– 

231–3228; email todd.thompson@faa.gov. 

(l) Material Incorporated by Reference 

(1) The Director of the Federal Register 

approved the incorporation by reference 

(IBR) of the material 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 this AD specifies otherwise. 

(i) European Union Aviation Safety Agency 

(EASA) AD 2024–0051, dated February 23, 

2024. 

(ii) [Reserved] 

(3) For EASA AD 2024–0051, contact 

EASA, Konrad-Adenauer-Ufer 3, 50668 

Cologne, Germany; telephone +49 221 8999 

000; email ADs@easa.europa.eu; website 

easa.europa.eu. You may find this EASA AD 

on the EASA website ad.easa.europa.eu. 

(4) 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. 

(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 September 23, 2024. 

Victor Wicklund, 

Deputy Director, Compliance & Airworthiness 

Division, Aircraft Certification Service. 

[FR Doc. 2024–24386 Filed 10–21–24; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2024–0229; Project 

Identifier AD–2023–00485–T; Amendment 

39–22848; AD 2024–19–06] 

RIN 2120–AA64 

Airworthiness Directives; The Boeing 

Company Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for certain 

The Boeing Company Model 737–8 and 

Model 737–9 airplanes. This AD was 

prompted by a Boeing review of the 

standby power system control unit 

(SPCU) design where a single point of 

failure exists internal to the SPCU. This 

AD requires installing four diodes and 

changing wire bundles in the P5 panel, 

as well as performing installation and 

power tests and applicable on-condition 

actions. The FAA is issuing this AD to 

address the unsafe condition on these 

products. 

DATES: This AD is effective November 

26, 2024 . 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in this AD 

as of November 26, 2024. 

ADDRESSES: 

AD Docket: You may examine the AD 

docket at regulations.gov under Docket 

No. FAA–2024–0229; 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 

address for Docket Operations is U.S. 

Department of Transportation, Docket 

Operations, M–30, West Building 

Ground Floor, Room W12–140, 1200 

New Jersey Avenue SE, Washington, DC 

20590. 

Material Incorporated by Reference: 

• For Boeing material identified in 

this AD, 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–2024–0229. 

FOR FURTHER INFORMATION CONTACT: Raja 

Vengadasalam, Aviation Safety 

Engineer, FAA, 2200 South 216th St., 

Des Moines, WA 98198; telephone 206– 

231–3537; email Raja.Vengadasalam@

faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 by adding an AD that would 

apply to certain The Boeing Company 

Model 737–8 and Model 737–9 

airplanes. The NPRM published in the 

Federal Register on February 14, 2024 

(89 FR 11231). The NPRM was 

prompted by a Boeing review of the 

SPCU design where a single point of 

failure exists internal to the SPCU. In 

the NPRM, the FAA proposed to require 

installing four diodes and changing wire 

bundles in the P5 panel, as well as 


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Federal Register / Vol. 89, No. 204 / Tuesday, October 22, 2024 / Rules and Regulations 84265 

performing installation and power tests 

and applicable on-condition actions. 

The FAA is issuing this AD to address 

a potential single point of failure in the 

SPCU, which can result in a non-latent 

loss of the entire battery bus and 

consequent un-annunciated loss of 

control and indication of both engine 

anti-ice (EAI) systems. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received comments from 

eight commenters who supported the 

NPRM without change. 

The FAA received additional 

comments from Alaska Airlines and two 

individuals. The following presents the 

comments received on the NPRM and 

the FAA’s response to each comment. 

Request for a ‘‘Credit for Previous 

Actions’’ Paragraph 

Alaska Airlines requested that the 

proposed AD be revised to include a 

‘‘Credit for Previous Actions’’ paragraph 

that gives credit as specified in 

paragraph (h)(2), ‘‘Exceptions to Service 

Information Specifications,’’ of the 

proposed AD. Alaska requested credit 

for ‘‘ACTION 3’’ in the Action column 

of the table in the ‘‘Compliance’’ 

paragraph of Boeing Alert Requirements 

Bulletin 737–30A1083 RB, dated 

November 18, 2022, for airplanes on 

which the requirements bulletin was 

embodied prior to the effective date of 

this AD. 

The FAA disagrees with revising this 

AD to include a ‘‘Credit for Previous 

Actions’’ paragraph in this AD. 

Paragraph (f), ‘‘Compliance,’’ of this AD 

provides credit for required actions 

performed before the effective date of 

this AD. The FAA has not changed this 

AD as a result of this comment. 

Request for Clarification of AD Actions 

An individual was supportive, but 

requested clarification of whether the 

proposed AD adequately addresses the 

unsafe condition to prevent the single 

point of failure addressed by the 

proposed AD. The commenter also 

questioned what is being done so this 

condition does not occur again, and 

whether this is the only issue with this 

airplane design. The commenter also 

requested clarification of whether the 

affected airplanes would be grounded 

until the proposed AD actions are 

completed. 

The FAA worked with Boeing to 

develop appropriate actions, i.e., the 

diode installation and wire bundle 

change, using the procedures specified 

in Boeing Alert Requirements Bulletin 

737–30A083 RB, dated November 18, 

2022, to address the identified unsafe 

condition in this AD. This particular 

issue is the only one addressed by this 

AD. The FAA continuously evaluates 

operator and manufacturer reports and 

other data in order to promote safe type 

certification and production. Operators 

are required to comply with all 

applicable actions of an AD within the 

required compliance time and cannot 

later undo those required actions. The 

FAA’s safety analysis has determined 

that the compliance time for corrective 

action in this AD provides an acceptable 

level of safety. The FAA has not 

changed this AD as a result of this 

comment. 

Request for FAA’s Approach to 

Continued Operational Safety 

Another individual stated that the AD 

‘‘prompted a review of’’ the SPCU and 

‘‘found a design flaw.’’ The commenter 

acknowledged that the proposed AD 

would address the underlying problem, 

but questioned how long the condition 

has existed, whether the SPCU review 

addresses all systems on these airplanes, 

and whether affected airplanes remain 

in service until the concerns are 

addressed. This commenter stated that a 

deeper review into other models and 

ways to address these issues must be 

investigated. 

The FAA provides the following 

clarification. This AD did not prompt 

the SPCU review; rather, after the SPCU 

review conducted by Boeing, the FAA 

determined that an AD was necessary 

and appropriate to address the unsafe 

condition. The FAA continuously 

receives and evaluates performance and 

safety data from operators and 

manufacturers on all type-certificated 

airplanes. The FAA takes corrective 

action—whether advisory such as an 

advisory circular or mandatory such as 

an AD—as warranted by the facts. The 

FAA has not changed this AD as a result 

of this comment. 

Conclusion 

The FAA reviewed the relevant data, 

considered any comments received, and 

determined that air safety requires 

adopting this AD as proposed. 

Accordingly, the FAA is issuing this AD 

to address the unsafe condition on these 

products. Except for minor editorial 

changes, this AD is adopted as proposed 

in the NPRM. None of the changes will 

increase the economic burden on any 

operator. 

Material Incorporated by Reference 

Under 1 CFR Part 51 

The FAA reviewed Boeing Alert 

Requirements Bulletin 737–30A083 RB, 

dated November 18, 2022. This material 

specifies procedures for installing four 

diodes and changing wire bundles in 

the P5 panel, as well as performing an 

anti-ice diode installation test and an 

engine anti-ice and wing anti-ice power 

test and applicable on-condition 

actions. On-condition actions include 

doing applicable corrective actions until 

the tests are passed. 

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. 

Costs of Compliance 

The FAA estimates that this AD 

affects 205 airplanes of U.S. registry. 

The FAA estimates the following costs 

to comply with this AD: 

ESTIMATED COSTS

Action Labor cost Parts cost Cost per product Cost on U.S. 

operators 

Installation, Wiring bundle changes, 

and tests.

Up to 18 work-hours × $85 per hour = 

Up to $1,530.

Up to $3,760 ......... Up to $5,290 ......... Up to $1,084,450. 

The FAA has received no definitive 

data on which to base the cost estimates 

for the on-condition actions specified in 

this AD. 

The FAA has included all known 

costs in its cost estimate. According to 

the manufacturer, however, some or all 

of the costs of this 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 


ddrumheller on DSK120RN23PROD with RULES1
84266 Federal Register / Vol. 89, No. 204 / Tuesday, October 22, 2024 / Rules and Regulations 

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, 

(2) Will not affect intrastate aviation 

in Alaska, and 

(3) Will 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 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: 

2024–19–06 The Boeing Company: 

Amendment 39–22848; Docket No. 

FAA–2024–0229; Project Identifier AD– 

2023–00485–T. 

(a) Effective Date 

This airworthiness directive (AD) is 

effective November 26, 2024. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to The Boeing Company 

Model 737–8 and 737–9 airplanes, 

certificated in any category, having a line 

number identified in paragraph 1.A., 

‘‘Effectivity,’’ of Boeing Alert Requirements 

Bulletin 737–30A1083 RB, dated November 

18, 2022. 

(d) Subject 

Air Transport Association (ATA) of 

America Code 30, Ice/Rain Protection 

System. 

(e) Unsafe Condition 

This AD was prompted by a Boeing review 

of the standby power system control unit 

(SPCU) design that determined a potential 

single point of failure exists in the SPCU. The 

FAA is issuing this AD to address a potential 

single point of failure in the SPCU, which 

can result in a non-latent loss of the entire 

battery bus and consequent un-annunciated 

loss of control and indication of both engine 

anti-ice (EAI) systems. The unsafe condition, 

if not addressed, could result in loss of thrust 

on both engines due to damage from 

operation in icing conditions without EAI 

and can result in loss of continued safe flight 

and landing. 

(f) Compliance 

Comply with this AD within the 

compliance times specified, unless already 

done. 

(g) Required Actions 

Except as specified by paragraph (h) of this 

AD: At the applicable times specified in the 

‘‘Compliance’’ paragraph of Boeing Alert 

Requirements Bulletin 737–30A1083 RB, 

dated November 18, 2022, do all applicable 

actions identified in, and in accordance with, 

the Accomplishment Instructions of Boeing 

Alert Requirements Bulletin 737–30A1083 

RB, dated November 18, 2022. 

Note 1 to paragraph (g): Guidance for 

accomplishing the actions required by this 

AD can be found in Boeing Alert Service 

Bulletin 737–30A1083, dated November 18, 

2022, which is referred to in Boeing Alert 

Requirements Bulletin 737–30A1083 RB, 

dated November 18, 2022. 

(h) Exceptions to Service Information 

Specifications 

(1) Where the Compliance Time columns 

of the table in the ‘‘Compliance’’ paragraph 

of Boeing Alert Requirements Bulletin 737– 

30A1083 RB, dated November 18, 2022, uses 

the phrase ‘‘the original issue date of 

Requirements Bulletin 737–30A1083 RB,’’ 

this AD requires using the effective date of 

this AD. 

(2) Where ‘‘ACTION 3’’ in the Action 

column of the table in the ‘‘Compliance’’ 

paragraph of Boeing Alert Requirements 

Bulletin 737–30A1083 RB, dated November 

18, 2022, specifies to do applicable corrective 

actions and repeat the test until the test 

passes if any test fails, for this AD, the 

compliance time for those actions is before 

further flight after accomplishing the test. 

(i) 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 AIR–520, Continued 

Operational Safety Branch, send it to the 

attention of the person identified in 

paragraph (j)(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. 

(j) Related Information 

(1) For more information about this AD, 

contact Raja Vengadasalam, Aviation Safety 

Engineer, FAA, 2200 South 216th St., Des 

Moines, WA 98198; telephone 206–231– 

3537; email Raja.Vengadasalam@faa.gov. 

(2) Material identified in this AD that is not 

incorporated by reference is available at the 

addresses specified in paragraph (k)(3) of this 

AD. 

(k) Material Incorporated by Reference 

(1) The Director of the Federal Register 

approved the incorporation by reference 

(IBR) of the material 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 Alert Requirements Bulletin 

737–30A1083 RB, dated November 18, 2022. 

(ii) [Reserved] 

(3) For Boeing material identified in this 

AD, 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/ 


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Federal Register / Vol. 89, No. 204 / Tuesday, October 22, 2024 / Rules and Regulations 84267 

ibr-locations.html or email fr.inspection@

nara.gov. 

Issued on September 13, 2024. 

Peter A. White, 

Deputy Director, Integrated Certificate 

Management Division, Aircraft Certification 

Service. 

[FR Doc. 2024–24369 Filed 10–21–24; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2024–0759; Project 

Identifier AD–2023–01040–T; Amendment 

39–22857; AD 2024–19–15] 

RIN 2120–AA64 

Airworthiness Directives; Safran 

Aerosystems (Formerly AVOX Systems 

Inc.; Scott Aviation) Oxygen Cylinder 

and Valve Assemblies, and Oxygen 

Valve Assemblies 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: The FAA is superseding 

Airworthiness Directive (AD) 2023–13– 

11, which applied to certain AVOX 

Systems Inc. (formerly Scott Aviation) 

oxygen cylinder and valve assemblies, 

and oxygen valve assemblies, installed 

on but not limited to various transport 

airplanes. AD 2023–13–11 required 

inspecting the oxygen valve assemblies, 

and oxygen cylinder and valve 

assemblies, to determine the serial 

number of the valve, cylinder, and 

entire assembly; inspecting certain 

assemblies and parts for correct spacing 

of the gap between the bottom of the 

packing retainer and top of the valve 

body on the assemblies, and replacing 

assemblies having unacceptable gaps. 

AD 2023–13–11 also limited the 

installation of affected parts and 

required reporting inspection results 

and returning certain assemblies to the 

manufacturer. This AD was prompted 

by the determination that additional 

assemblies and parts are subject to the 

unsafe condition. This AD requires the 

actions specified in AD 2023–13–11 and 

expands the list of affected assemblies 

and parts. The FAA is issuing this AD 

to address the unsafe condition on these 

products. 

DATES: This AD is effective November 

26, 2024. 

The Director of the Federal Register 

approved the incorporation by reference 

of certain publications listed in this AD 

as of November 26, 2024. 

The Director of the Federal Register 

approved the incorporation by reference 

of certain other publications listed in 

this AD as of September 5, 2023 (88 FR 

50011, August 1, 2023). 

ADDRESSES: 

AD Docket: You may examine the AD 

docket at regulations.gov under Docket 

No. FAA–2024–0759; 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 

address for Docket Operations is U.S. 

Department of Transportation, Docket 

Operations, M–30, West Building 

Ground Floor, Room W12–140, 1200 

New Jersey Avenue SE, Washington, DC 

20590. 

Material Incorporated by Reference: 

• For AVOX and Safran Aerosystems 

material identified in this AD, contact 

AVOX Systems Inc., 225 Erie Street, 

Lancaster, NY 14086; telephone 716– 

683–5100; website 

safranaerosystems.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–2024–0759. 

FOR FURTHER INFORMATION CONTACT: 

Gabriel Kim, Aviation Safety Engineer, 

FAA, 1600 Stewart Avenue, Suite 410, 

Westbury, NY 11590; telephone 516– 

228–7300; email 9-avs-nyaco-cos@

faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 to supersede AD 2023–13–11, 

Amendment 39–22496 (88 FR 50011, 

August 1, 2023) (AD 2023–13–11). AD 

2023–13–11 applied to certain AVOX 

Systems Inc. (formerly Scott Aviation) 

oxygen cylinder and valve assemblies, 

and oxygen valve assemblies, installed 

on but not limited to various transport 

airplanes. AD 2023–13–11 was 

prompted by reports of cylinder and 

valve assemblies having oxygen leakage 

from the valve assembly vent hole, 

caused by the absence of a guide that 

maintains appropriate spacing between 

certain parts, and by a determination 

that additional assemblies and parts are 

affected by the unsafe condition 

addressed by AD 2022–04–09, 

Amendment 39–21951 (87 FR 10958, 

February 28, 2022) (AD 2022–04–09) 

(which was superseded by AD 2023–13– 

11). 

The NPRM published in the Federal 

Register on March 25, 2024 (89 FR 

20558). The NPRM was prompted by a 

report that the manufacturer identified 

additional assemblies and parts subject 

to the unsafe condition. In the NPRM, 

the FAA proposed to continue to require 

the actions specified in AD 2023–13–11 

and require similar actions for those 

additional assemblies and parts. The 

FAA is issuing this AD to address 

oxygen leakage from the cylinder and 

valve assemblies, which could result in 

decreased or insufficient oxygen supply 

during a depressurization event; and 

heating or flow friction, which could 

cause an ignition event in the valve 

assembly. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received comments from 

four commenters, including Alaska 

Airlines (Alaska), American Airlines, 

Cathay Pacific Airways, Delta Air Lines 

(Delta), and SIAEC (SIA Engineering 

Company). The following presents the 

comments received on the NPRM and 

the FAA’s response to each comment. 

Request To Reference Later Revisions 

of Material Identified as Credit 

Alaska requested adding the required 

revisions of the material (identified in 

paragraphs (l)(1) through (3) of the 

proposed AD) to the group of material 

identified as acceptable material in 

paragraph (p)(3) of the proposed AD for 

actions accomplished before the 

effective date of this AD. 

The FAA disagrees with the request to 

revise paragraph (p)(3) of this AD. A 

global alternative method of compliance 

(AMOC) letter, 753–23–00200, was 

issued for AD 2023–13–11 that 

identified the required material in 

paragraphs (l)(1) through (3) of this AD 

as an acceptable AMOC. 

Accomplishment of the required 

material before the effective date of this 

AD to comply with the requirements of 

this AD is addressed by paragraph (f) of 

this AD. Paragraph (f) of this AD allows 

for the use of the required material 

before the effective date of this AD. No 

change to the AD has been made in this 

regard. 

Request for Clarification on Acceptable 

Material for Credit Conclusion 

SIAEC asked if credit can be granted 

for the actions specified in paragraphs 

(h) and (i) of the proposed AD if 

Revision 03 of the material was used. 

The FAA agrees to clarify. Paragraphs 

(h) and (i) of this AD still reference 

Revision 03 of the material as the 

primary means of compliance for those 


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