DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-0015; Project Identifier AD-2022-01281-T;
Amendment 39-22496; AD 2023-13-11]
RIN 2120-AA64

Airworthiness Directives; AVOX Systems Inc. (Formerly Scott
Aviation) Oxygen Cylinder and Valve Assemblies; and Oxygen Valve
Assemblies

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2022-04-
09, 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 2022-04-09 required an inspection of the oxygen valve
assemblies, and oxygen cylinder and valve assemblies, to determine the
serial number; for certain assemblies and parts, a detailed inspection
of the gap between the bottom of the packing retainer and top of the
valve body on the assemblies; and replacement of assemblies having
unacceptable gaps. This AD was prompted by a determination that
additional assemblies and parts are affected by the unsafe condition.
This AD requires an inspection of the oxygen valve assemblies, and
oxygen cylinder and valve assemblies, to determine the serial number of
the valve, cylinder, and entire assembly; for certain assemblies and
parts, a detailed inspection for correct spacing of the gap between the
bottom of the packing retainer and top of the valve body on the
assemblies and replacement of assemblies having unacceptable gaps. This
AD also limits the installation of affected parts under certain
conditions and reporting inspection results and returning certain
assemblies to the manufacturer. The FAA is issuing this AD to address
the unsafe condition on these products.

DATES: This AD is effective September 5, 2023.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of September 5,
2023.

ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2023-0015; 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 service information identified in this final rule,
contact AVOX Systems Inc., 225 Erie Street, Lancaster, NY 14086;
telephone 716-683-5100; website safranaerosystems.com.
You may view this service information 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-2023-0015.

FOR FURTHER INFORMATION CONTACT: Elizabeth Dowling, 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 2022-04-09, Amendment 39-21951 (87 FR
10958, February 28, 2022) (AD 2022-04-09). AD 2022-04-09 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 2022-04-09 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. The NPRM published
in the Federal Register on January 27, 2023 (88 FR 5278). The NPRM was
prompted by a determination that additional assemblies and parts are
affected by the unsafe condition. In the NPRM, the FAA proposed to
continue to require an inspection of the oxygen valve assemblies, and
oxygen cylinder and valve assemblies, to determine the serial number of
the valve, cylinder, and entire assembly. For assemblies and parts with
certain serial numbers, the FAA also proposed to continue to require a
detailed inspection for correct spacing of the gap between the bottom
of the packing retainer and top of the valve body on the assemblies,
and replacement of assemblies having unacceptable gaps. The NPRM also
proposed to limit the installation of affected parts under certain
conditions and reporting inspection results and returning certain
assemblies to the manufacturer. 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 Atlas
Air, Aviation Partners Boeing, FlyPersia Airlines, and SIA Engineering.
The following presents the comments received on the NPRM and the FAA's
response to each comment.

Effect of Winglets on Accomplishment of the Proposed Actions

Aviation Partners Boeing stated that the installation of winglets
per Supplemental Type Certificate (STC) ST00830SE, STC ST01219SE, STC
ST01518SE, and STC ST01920SE does not affect the accomplishment of the
manufacturer's service instructions.
The FAA agrees with the commenter that STC ST00830SE, STC
ST01219SE, STC ST01518SE, and STC ST01920SE do not affect the
accomplishment of the manufacturer's service instructions. Therefore,
the installation of STC ST00830SE, STC ST01219SE, STC ST01518SE, and
STC ST01920SE do not affect the ability to accomplish the actions
required by this AD. The FAA has not changed this AD in this regard.

Request To Change the Applicability for Certain Airplanes

FlyPersia Airlines requested that paragraph (c)(12) of the proposed
AD be changed to ``The Boeing Company Airplanes.'' The commenter
asserted that some of the affected oxygen cylinder and valve assemblies
may be installed on other Boeing airplanes.
The FAA does not agree with the change requested. The applicability
of this AD includes the airplane models that are known to be affected.
However, as stated in paragraph (c) of this AD, the affected oxygen
cylinder and valve assemblies might be installed on, but are not
limited to, the aircraft identified in paragraphs (c)(1) through (12)
of this AD, certificated in any category. This AD has not been changed
in regard to this request.

Request for Clarification on Compliance of a Specific Airplane

SIA Engineering requested clarification on whether Boeing Model
737-8 airplane, Manufacturer Serial Number (MSN) 44257, is in
compliance with the proposed AD. The commenter declared that the
airplane was delivered in May of 2022 and was in compliance with AD
2022-04-09. The commenter also pointed out that the proposed AD
provided credit for the service information that was required by AD
2022-04-09 and asked if credit may be taken for airplanes that have
complied with AD 2022-04-09 and reported the results as required by
that AD.
The FAA agrees to clarify. An airplane without a part identified in
paragraph (c) of this AD is not affected by this AD. However, an
airplane delivered without an affected part, but on which the part was
later replaced with an affected part (one identified in paragraph (c)
of this AD) is affected by this AD and must comply with this AD; this
includes complying with the revised parts installation prohibition
specified in paragraph (k) of this AD.

Request To Correct Typographical Error

Atlas Air and SIA Engineering noted a typographical error in the
regulatory text of the proposed AD. The commenters pointed out that the
paragraph designation of the Parts Installation Limitation paragraph
should have been designated as paragraph (k) of the proposed AD.
The FAA agrees and has redesignated that paragraph, and subsequent
paragraphs, accordingly.

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, and
any other changes described previously, this AD is adopted as proposed
in the NPRM. None of the changes will increase the economic burden on
any operator.

Related Service Information Under 1 CFR Part 51

The FAA reviewed the following service information, which describes
procedures for an inspection to determine the serial numbers of the
oxygen cylinder and valve assemblies, and the oxygen valve assemblies,
a detailed inspection for correct spacing of the gap between the bottom
of the packing retainer and top of the valve body on the assemblies,
parts marking, inspection report, and return of parts to the
manufacturer. These documents are distinct since they apply to
different assembly part numbers.
AVOX Systems Inc. Alert Service Bulletin 10015804-35-01,
Revision 03, dated June 7, 2021.
AVOX Systems Inc. Alert Service Bulletin 10015804-35-02,
Revision 03, dated March 11, 2022.
AVOX Systems Inc. Alert Service Bulletin 10015804-35-03,
Revision 03, dated June 18, 2021.
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 the ADDRESSES section.

Costs of Compliance

The FAA estimates that this AD affects 3,034 oxygen cylinder and
valve assemblies, and oxygen valve assemblies, installed on various
transport category 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 follow-on
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 actions:

On-Condition Costs

* The FAA has received no definitive data on the parts cost for the on-condition
replacements.

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.

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to a penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a currently valid OMB Control Number. The OMB
Control Number for this information collection is 2120-0056. Public
reporting for this collection of information is estimated to take
approximately 1 hour per response, including the time for reviewing
instructions, searching existing data sources, gathering and
maintaining the data needed, and completing and reviewing the
collection of information. All responses to this collection of
information are mandatory. Send comments regarding this burden estimate
or any other aspect of this collection of information, including
suggestions for reducing this burden to: Information Collection
Clearance Officer, Federal Aviation Administration, 10101 Hillwood
Parkway, Fort Worth, TX 76177-1524.

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,
(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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by:

a. Removing Airworthiness Directive (AD) 2022-04-09, Amendment 39-21951
(87 FR 10958, February 28, 2022); and

b. Adding the following new AD: