DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0462; Project Identifier MCAI-2021-00647-T]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain The Boeing Company Model 737-700, 737-800, 747-400, 747-8,
767-400ER, and 777-200 airplanes. This proposed AD was prompted by a
report that there is the potential for electrical current to pass
through low pressure (LP) oxygen flex-hoses in the gaseous passenger
oxygen system. This proposed AD would require replacing each conductive
oxygen flex-hose installed on LP gaseous passenger oxygen systems with
a serviceable non-conductive oxygen flex-hose. This proposed AD would
also prohibit installation of a conductive oxygen flex-hose on LP
gaseous passenger oxygen systems. 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 6,
2022.

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 Lufthansa
Technik AG, Weg beim J[auml]ger 193 22335 Hamburg, Germany; telephone
49-40-5070-67428; internet https://www.lufthansa-technik.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 at https://www.regulations.gov by
searching for and locating Docket No. FAA-2022-0462; 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, any comments
received, and other information. The street address for Docket
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Chirayu Gupta, Aerospace Engineer,
Mechanical Systems and Administrative Services Section, FAA, New York
ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
telephone 516-228-7300; 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 ADDRESSES. Include ``Docket No. FAA-2022-0462; Project Identifier
MCAI-2021-00647-T'' at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, 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
the proposal 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
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this NPRM.

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 NPRM 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 NPRM, 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 NPRM. Submissions containing CBI should be sent to
Chirayu Gupta, Aerospace Engineer, Mechanical Systems and
Administrative Services Section, FAA, New York ACO Branch, 1600 Stewart
Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; fax 516-
794-5531; email 9-avs-nyaco-cos@faa.gov. Any commentary that the FAA
receives which is not specifically designated as CBI will be placed in
the public docket for this rulemaking.

Background

The European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Union, has issued
EASA AD 2021-0135, dated June 2, 2021 (EASA AD 2021-0135) (also
referred to after this as the Mandatory Continuing Airworthiness
Information, or the MCAI), to correct an unsafe condition for certain
The Boeing Company Model 737-700, 737-800, 747-400, 747-8, 767-400ER,
and 777-200 airplanes with certain Lufthansa Technik AG supplemental
type certificates (STCs). Those STCs are not validated by the FAA; this
proposed AD therefore refers to the corresponding FAA STC, STC
ST04127NY, instead in the applicability. You may examine the MCAI in
the AD docket at https://www.regulations.gov by searching for and
locating Docket No. FAA-2022-0462.
This proposed AD was prompted by a report that there is the
potential for electrical current to pass through LP oxygen flex-hoses
in the gaseous passenger oxygen system. Exposure to electrical faults,
such as unintended short circuits, can result in localized electrical
heating of the LP oxygen flex-hoses. The FAA issued AD 2018-09-12,
Amendment 39-19269 (83 FR 22360,
May 15, 2018) (AD 2018-09-12), for certain The Boeing Company Model
747-200B, -300, and -400 series airplanes; and AD 2019-25-12, Amendment
39-21010 (85 FR 449, dated January 6, 2020) (AD 2019-25-12), for
certain The Boeing Company Model 777-200 and -300ER series airplanes.
AD 2018-09-12 and AD 2019-25-12 require replacing the LP oxygen flex-
hoses with new non-conductive LP oxygen flex-hoses in the gaseous
passenger oxygen system in airplanes equipped with therapeutic oxygen.
The same conductive oxygen flex-hoses affected by those ADs have also
been installed on airplanes modified by the Lufthansa Technik AG STCs
and FAA STC that are the subject of this AD but were not part of the
applicability of AD 2018-09-12 and AD 2019-25-12. The FAA is proposing
this AD to address the possibility of electrical current passing
through the LP oxygen flex-hoses in the gaseous passenger oxygen
system, which could cause the flex-hoses to melt or burn and result in
an oxygen-fed fire in the passenger cabin. See the MCAI for additional
background information.

Related Service Information Under 1 CFR Part 51

Lufthansa Technik AG has issued the following service information.
Lufthansa Technik Design Change Summary ASN-00-DCS-01,
Revision 8, dated November 5, 2020.
Lufthansa Technik Design Change Summary ATB-25-DCS-01,
Revision 10, dated January 7, 2021.
Lufthansa Technik Design Change Summary ATR-23-DCS-01,
Revision 2, dated January 21, 2021.
Lufthansa Technik Design Change Summary BCM-35-DCS-01,
dated January 4, 2021.
Lufthansa Technik Design Change Summary BCP-35-DCS-01,
Revision 1, dated April 20, 2021.
Lufthansa Technik Design Change Summary BCQ-35-DCS-01,
Revision 1, dated April 20, 2021.
Lufthansa Technik Design Change Summary BCR-35-DCS-01,
Revision 1, dated April 20, 2021.
Lufthansa Technik Design Change Summary BCS-35-DCS-01,
dated January 5, 2021.
Lufthansa Technik Design Change Summary BCU-35-DCS-01,
dated January 5, 2021.
Lufthansa Technik Design Change Summary BCV-35-DCS-01,
dated February 4, 2021.
Lufthansa Technik Design Change Summary BCW-35-DCS-01,
dated January 4, 2021.
Lufthansa Technik Design Change Summary BCX-35-DCS-01,
Revision 1, dated February 4, 2021.
This service information describes procedures for replacing each
conductive oxygen flex-hose installed on LP gaseous passenger oxygen
systems with a serviceable non-conductive oxygen flex-hose. These
documents are distinct since they apply to different airplane models
and manufacturer serial 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

This product has been approved by the aviation authority of another
country, and is approved for operation in the United States. Pursuant
to the FAA's bilateral agreement with the State of Design Authority,
the FAA has been notified of the unsafe condition described in the MCAI
and service information referenced above. 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
on other products of the same type design.

Proposed AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified
in the service information already described. This proposed AD would
also prohibit installation of a conductive oxygen flex-hose on LP
gaseous passenger oxygen systems.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 7 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:

Estimated Costs for Required Actions

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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive: