DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0345; Product Identifier 2019-NM-154-AD]
RIN 2120-AA64

Airworthiness Directives; AVOX System Inc. (formerly Scott Aviation)
Oxygen Cylinder and Valve Assemblies; and Oxygen Valve Assemblies

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) for
certain AVOX System Inc. (formerly Scott Aviation) oxygen cylinder and
valve assemblies; and oxygen valve assemblies; installed on but not
limited to various transport airplanes. This proposed AD 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. This proposed AD would 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,
this AD would 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 FAA is proposing this AD to address the unsafe condition on these
products.

DATES: The FAA must receive comments on this proposed AD by June 15, 2020.

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 https://www.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.

For service information identified in this NPRM, contact AVOX Systems Inc.
225 Erie Street, Lancaster, NY 14086; telephone 716-683-5100; Internet
https://www.safran-aerosystems.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.

Examining the AD Docket

You may examine the AD docket on the Internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2020-0345; 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, the regulatory
evaluation, any comments received, and other information. The street
address for Docket Operations is listed above. Comments will be available
in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Darren Gassetto, Aerospace
Engineer, Mechanical Systems and Administrative Services Section, FAA, New
York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; tele-
phone 516-228-7323; fax 516-794-5531; email 9-avs-nyaco-cos@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 the
ADDRESSES section. Include "Docket No. FAA-2020-0345; Product Identifier
2019-NM-154-AD" at the beginning of your comments. The FAA specifically
invites comments on the overall regulatory, economic, environmental, and
energy aspects of this NPRM. The FAA will consider all comments received
by the closing date and may amend this NPRM because of those comments.

The FAA will post all comments, without change, to https://www.regulations
.gov, including any personal information you provide. The FAA will also
post a report summarizing each substantive verbal contact received about
this NPRM.

Discussion

The FAA has received 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. It was
determined that this guide was not installed during manufacturing,
resulting in the O-ring and backup ring not being sufficiently constrained
with the valve assembly. This condition, if not addressed, could result in
oxygen leakage from the cylinder, leading to decreased or insufficient
oxygen supply during a depressurization event; and heating or flow
friction, which could cause an ignition event in the valve assembly.

Related Service Information Under 1 CFR Part 51

The FAA reviewed AVOX Systems Inc., Alert Service Bulletins 10015804-35
-01, Revision 02, dated October 16, 2019; 10015804-35-02, Revision 2,
dated October 31, 2019; and 10015804-35-03, Revision 02, dated October 15,
2019. This service information describes procedures for an inspection to
determine the serial number 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. These documents are distinct since they apply to
different assembly part numbers. 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.

FAA’s Determination

The FAA is proposing this AD because the FAA evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

This proposed AD would 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, this AD would 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 gap (removing affected
assemblies and installing serviceable assemblies). This proposed AD would
also require reporting and the return of affected parts to the
manufacturer.

Clarification of Inspection Terminology

In this proposed AD, the "visual inspection" specified in the AVOX Systems
Inc., service bulletins is referred to as a "detailed inspection." The FAA
has included the definition for a detailed inspection in this proposed AD.

Clarification of Inspection Requirements

AVOX Systems Inc., Alert Service Bulletins 10015804-35-01, Revision 02,
dated October 16, 2019; 10015804-35-02, Revision 2, dated October 31,
2019; and 10015804-35-03, Revision 02, dated October 15, 2019, specify to
inspect to determine the serial number of the oxygen cylinder and valve
assemblies; and the oxygen valve assemblies. However, the valve and
cylinder that are part of those assemblies must also be inspected, not
just the assemblies themselves. Therefore, in this proposed AD, the FAA
specifies to inspect the oxygen valve assemblies, and oxygen cylinder and
valve assemblies, to determine the serial number of the valve, cylinder,
and entire assembly.

Costs of Compliance

The FAA estimates that this proposed AD affects up to 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 proposed 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 proposed
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 cost of on-condition replacements.

According to the manufacturer, some or all of the costs of this proposed
AD may be covered under warranty, thereby reducing the cost impact on
affected individuals. The FAA does not control warranty coverage for
affected individuals. As a result, the FAA has included all known costs in
our cost estimate.

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 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
current valid OMB control number. The control number for the collection of
information required by this proposed AD is 2120-0056. The paperwork cost
associated with this proposed AD has been detailed in the Costs of
Compliance section of this document and includes time for reviewing
instructions, as well as completing and reviewing the collection of
information. Therefore, all reporting associated with this proposed AD is
mandatory. Comments concerning the accuracy of this burden and suggestions
for reducing the burden should be directed 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

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) 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 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.

§ 39.13 [Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness
directive (AD):