Proposed Rule2023-12695
Airworthiness Directives; General Electric Company Turbofan Engines
Primary source
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Published
June 14, 2023
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is withdrawing a notice of proposed rulemaking (NPRM) that proposed to adopt a new airworthiness directive (AD) for certain General Electric Company (GE) CF6-80E1A2, CF6-80E1A3, CF6-80E1A4, and CF6-80E1A4/B model turbofan engines. The NPRM was prompted by a manufacturer investigation that revealed that certain compressor discharge pressure seals (CDP seals) and forward outer seals were manufactured from powder metal material suspected to contain iron inclusion. The NPRM proposed to require the replacement of the affected CDP seals and forward outer seals. Since issuance of the NPRM, the FAA has reviewed subsequent information received from the manufacturer and determined that the unsafe condition is not likely to exist or develop in other products of the same type design. Accordingly, the NPRM is withdrawn.
Full Text
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<title>Federal Register, Volume 88 Issue 114 (Wednesday, June 14, 2023)</title>
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[Federal Register Volume 88, Number 114 (Wednesday, June 14, 2023)]
[Proposed Rules]
[Pages 38758-38759]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-12695]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 88 , No. 114 / Wednesday, June 14, 2023 /
Proposed Rules
[[Page 38758]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2022-1401; Project Identifier AD-2022-01017-E]
RIN 2120-AA64
Airworthiness Directives; General Electric Company Turbofan
Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Proposed rule; withdrawal.
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SUMMARY: The FAA is withdrawing a notice of proposed rulemaking (NPRM)
that proposed to adopt a new airworthiness directive (AD) for certain
General Electric Company (GE) CF6-80E1A2, CF6-80E1A3, CF6-80E1A4, and
CF6-80E1A4/B model turbofan engines. The NPRM was prompted by a
manufacturer investigation that revealed that certain compressor
discharge pressure seals (CDP seals) and forward outer seals were
manufactured from powder metal material suspected to contain iron
inclusion. The NPRM proposed to require the replacement of the affected
CDP seals and forward outer seals. Since issuance of the NPRM, the FAA
has reviewed subsequent information received from the manufacturer and
determined that the unsafe condition is not likely to exist or develop
in other products of the same type design. Accordingly, the NPRM is
withdrawn.
DATES: As of June 14, 2023, the proposed rule, which published in the
Federal Register on November 4, 2022 (87 FR 66625), is withdrawn.
ADDRESSES: AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a>
by searching for and locating Docket No. FAA-2022-1401; 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 AD action, any
comments received, and other information. The street address for Docket
Operations is Docket Operations, M-30, West Building Ground Floor, Room
W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: Alexei Marqueen, Aviation Safety
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone:
(781) 238-7178; email: <a href="/cdn-cgi/l/email-protection#dbbab7bea3beb2f5aff5b6baa9aaaebebeb59bbdbabaf5bcb4ad"><span class="__cf_email__" data-cfemail="abcac7ced3cec285df85c6cad9dadececec5ebcdcaca85ccc4dd">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Background
The FAA issued an NPRM that proposed to amend 14 CFR part 39 by
adding an AD that would apply to certain GE CF6-80E1A2, CF6-80E1A3,
CF6-80E1A4, and CF6-80E1A4/B model turbofan engines. The NPRM published
in the Federal Register on November 4, 2022 (87 FR 66625). The NPRM was
prompted by notification from the manufacturer of the detection of iron
inclusion in a turbine disk manufactured from the same powder metal
material used to manufacture certain CDP seals and a certain forward
outer seal. Further investigation by the manufacturer determined that
certain CDP seals and a certain forward outer seal made from billets
manufactured using the same process may have reduced material
properties and a lower fatigue life capability due to iron inclusion,
which may cause premature fracture and uncontained failure.
The NPRM proposed to require the removal of certain CDP seals and a
certain forward outer seal from service and replacement with a part
eligible for installation. The proposed actions were intended to
prevent fracture and uncontained failure of certain CDP seals and a
certain forward outer seal, which could result in uncontained debris
release, damage to the engine, and damage to the aircraft.
Actions Since the NPRM Was Issued
Since issuance of the NPRM, the FAA and the manufacturer have
determined that the affected CDP seals have met their full Chapter 5
life of 15,000 cycles and are not subject to the unsafe condition.
Since there is only one affected forward outer seal, identified by part
number and serial number, the FAA has determined that the unsafe
condition is not likely to exist or develop in other products of the
same type design. Therefore, the FAA has determined that this AD action
is not appropriate. However, the FAA may publish a separate rulemaking
to address the unsafe condition in the specified forward outer seal.
Withdrawal of the NPRM constitutes only such action and does not
preclude the FAA from further rulemaking on this issue, nor does it
commit the FAA to any course of action in the future.
Comments
The FAA received comments from three commenters. The commenters
were Delta Air Lines, Inc. (DAL), GE, and an anonymous commenter. The
anonymous commenter supported the NPRM without change. The following
presents the comments received on the NPRM and the FAA's response.
Request To Remove CDP Seals From the Proposed AD
GE requested the removal of CDP seals with part number (P/N)
1669M73P02 and serial numbers (S/N) TMT1C0E1 or TMT1C0E2 entirely from
the NPRM. GE stated that this P/N has been assessed to meet its full
Chapter 5 life of 15,000 cycles and, therefore, will not result in
premature fracture and uncontained failure and, accordingly, no unsafe
condition exists for these CDP seals.
The FAA agrees and is withdrawing the AD in response to this
comment.
Request To Expand Applicability To Include Additional Engine Models
DAL requested the FAA expand the applicability of the proposed AD
by adding CF6-80C2B2F/B6F/B7F/B8F model turbofan engines because the
CF6-80C2 Engine Illustrated Parts Catalog identifies affected forward
outer seal P/N 1778M70P03 as a part installed on those model turbofan
engines. DAL stated that it is possible that parts were intermixed
across models during previous engine shop visits, necessitating a
review of operator CF6-80C2 fleets for the affected serial number.
The FAA disagrees. Providing both the P/N (1778M70P03) and S/N
(NCU65340) of the affected forward outer seal is sufficient information
to identify which engine model is affected since it is a single tracked
part.
Request To Clarify Disposition of Removed Parts
DAL requested that the FAA clarify the disposition of removed parts
in
[[Page 38759]]
paragraph (g) of the proposed AD. The commenter stated that paragraph
(g) of the proposed AD, Required Actions, states to remove the affected
CDP seal or forward outer seal from service. DAL stated that there is
no clear statement that the parts could not be returned to service, yet
further commented that paragraph (i) of the proposed AD, Installation
Prohibition, ensures that the parts may not be installed. DAL commented
that requiring disposal of the affected parts will ensure the parts do
not enter the materials market.
The FAA disagrees. The FAA does not have the authority to require
operators to discard parts to address an unsafe condition. Within the
scope of an AD, removing parts from service and prohibiting
installation is within the FAA's authority.
Request To Revise Definition of ``Piece-Part Exposure''
DAL and GE requested that the FAA revise the definition of ``piece-
part exposure'' in paragraph (h)(2) of the proposed AD. DAL stated that
paragraph (h)(2) of the proposed AD defines piece-part exposure as when
the affected part is removed from the engine. DAL suggested this be
specified as removal of the affected part from the mating structures
instead. The commenter reasoned that the current wording could indicate
that if the module an affected part is installed in is removed from the
engine, replacement of the affected part is required. GE stated that
the current definition of ``piece-part exposure'' is unclear and
suggested clarifying paragraph (h)(2) of the proposed AD to read, ``For
the purpose of this AD, ``piece-part exposure'' is when the affected
part is removed from the engine and completely disassembled.''
Because the FAA is withdrawing the NPRM, the clarification of
paragraph (h)(2) of the proposed AD is no longer necessary.
Regulatory Findings
Since this action only withdraws an NPRM, it is neither a proposed
nor a final rule. This action therefore is not covered under Executive
Order 12866 or the Regulatory Flexibility Act.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
The Withdrawal
0
Accordingly, the notice of proposed rulemaking, Docket No. FAA-2022-
1401; Project Identifier AD-2022-01017-E which published in the Federal
Register on November 4, 2022 (87 FR 66625), is withdrawn.
Issued on June 8, 2023.
Michael Linegang,
Acting Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2023-12695 Filed 6-13-23; 8:45 am]
BILLING CODE 4910-13-P
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