DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0766; Project Identifier 2019-NE-23-AD]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turbofan
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (SNPRM).

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SUMMARY: The FAA is revising a notice of proposed rulemaking (NPRM)
that applied to all General Electric Company (GE) CF34-8C1, CF34-8C5,
CF34-8C5A1, CF34-8C5B1, CF34-8C5A2, CF34-8C5A3, CF34-8E2, CF34-8E2A1,
CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 model
turbofan engines. This action revises the NPRM by updating the service
information references and removing the initial and repetitive
fluorescent penetrant inspections (FPIs) of the combustion chamber
assembly. The FAA is proposing this airworthiness directive (AD) to
address the unsafe condition on these products. Since these actions
change the required actions as proposed in the NPRM, the agency is
requesting comments on this SNPRM.

DATES: The FAA must receive comments on this SNPRM by November 21,
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 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.
AD Docket: You may examine the AD docket at regulations.gov by
searching for and locating Docket No. FAA-2019-0766; or in person at
Docket Operations between 9 a.m. and 5 p.m., Monday through Friday,
except Federal holidays. The AD docket contains the NPRM, this SNPRM,
any comments received, and other information. The street address for
Docket Operations is listed above.
Material Incorporated by Reference:
For GE service information identified in this SNPRM,
contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215;
phone: (513) 552-3272; email: ge.com">aviation.fleetsupport@ge.com; website:
ge.com.
You may view this service information at the FAA,
Airworthiness Products Section, Operational Safety Branch, 1200
District Avenue, Burlington, MA 01803. For information on the
availability of this material at the FAA, call (817) 222-5110.

FOR FURTHER INFORMATION CONTACT: Scott Stevenson, Aviation Safety
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803;
phone: (781) 238-7132; email: Scott.M.Stevenson@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-2019-0766; Project Identifier
2019-NE-23-AD'' 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 again revise this 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
regulations.gov, including any personal information you provide. The
agency will also post a report summarizing each substantive verbal
contact received about this proposed AD.

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 SNPRM 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 SNPRM, 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 SNPRM. Submissions containing CBI should
be sent to Scott Stevenson, Aviation Safety Engineer, ECO Branch, FAA,
1200 District Avenue, Burlington, MA 01803. 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 FAA issued an NPRM to amend 14 CFR part 39 by adding an AD that
would apply to all GE CF34-8C1, CF34-8C5, CF34-8C5A1, CF34-8C5B1, CF34-
8C5A2, CF34-8C5A3, CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-
8E5A2, CF34-8E6, and CF34-8E6A1 (CF34-8C and GE CF34-8E) model turbofan
engines, including engine models marked on engine data plate as CF34-
8C5/B, CF34-8C5/M, CF34-8C5A1/B, CF34-8C5A1/M, CF34-8C5B1/B, CF34-
8C5A2/B, and CF34-8C5A2/M. The NPRM published in the Federal Register
on December 3, 2019 (84 FR 66082). The NPRM was prompted by a predicted
reduction in the cyclic life of the combustion chamber assembly aft
flange. As a result, the manufacturer added a scheduled maintenance
check. In the NPRM, the FAA proposed to require revisions to the
airworthiness limitations section (ALS) of the manufacturer's
instructions for continued airworthiness and the air carrier's approved
continued airworthiness maintenance program to
incorporate initial and repetitive FPIs of the combustion chamber
assembly.

Actions Since the NPRM Was Issued

Since the FAA issued the NPRM, the manufacturer incorporated the
temporary revisions (TRs) into the GE CF34-8C and GE CF34-8E engine
manuals (EMs). Based on the revised service information, the FAA has
revised the proposal by removing paragraph (g)(2) from the NPRM, which
proposed to require initial and repetitive FPIs of the combustion
chamber assembly installed on GE CF34-8C and GE CF34-8E model turbofan
engines.

Comments

The following discussion presents the comments received on the NPRM
and the FAA's response.

Request To Change References From TRs to EMs

Horizon Air and Japan Airlines (JAL) requested that the FAA revise
the references GE CF34-8E EM TR 05-0085, dated February 21, 2019, and
GE CF34-8E TR 05-0086, dated February 13, 2019, because the TRs have
since been incorporated into the GE CF34-8C and GE CF34-8E EMs, as
applicable.
In response to these comments, the FAA has revised this proposed AD
by replacing GE CF34-8E EM TR 05-0085, dated February 21, 2019; GE
CF34-8C TR 05-0141, dated February 21, 2019; GE CF34-8C TR 05-0143,
dated February 13, 2019; GE CF34-8E TR 05-0086, dated February 13,
2019; and GE CF34-8C TR 05-0142, dated February 13, 2019, with the
applicable tasks in the GE CF34-8C or GE CF34-8E EM.

Request To Add FPI Procedure for the Disassembled (Off-Wing) Engine

JAL requested that the FAA add the FPI procedure to paragraph
(g)(2)(i) of this proposed AD, as specified in TASK 72-41-01-200-801,
of GE CF34-8E EM GEK112031 for the disassembled (off-wing) engine. JAL
reasoned that TASK 05-21-03-200-801 from ESM 05-21-03 Airworthiness
Limitations--Mandatory Inspection 001, of GE CF34-8E EM GEK112031,
which incorporated GE CF34-8E TR 05-0086, dated February 13, 2019,
refers to TASK 72-41-01-200-801, on-wing inspections.
The FAA disagrees with the request to add disassembled or off-wing
FPI procedures to this proposed AD. Since TASK 72-41-01-200-801 and
TASK 72-41-01-200-801 are not referenced in GE CF34-8E EM GEK112031,
the FAA interprets JAL's comment as a request to add TASK 72-00-41-200-
806, as referenced in GE CF34-8E EM GEK112031. Additionally, the FAA
has determined that the FPIs proposed in the NPRM are not required to
address the unsafe condition. Therefore, the FAA has removed the
proposed FPI of the combustion chamber assembly, paragraph (g)(2), as
proposed in the NPRM, from this proposed SNPRM.

Support for the AD

The Air Line Pilots Association, International expressed support
for the AD as written.

FAA's Determination

The FAA is proposing this AD after determining the unsafe condition
described previously is likely to exist or develop in other products of
the same type design. Certain changes described above revise the scope
of the NPRM. As a result, it is necessary to reopen the comment period
to provide additional opportunity for the public to comment on this
SNPRM.

Related Service Information Under 1 CFR Part 51

The FAA reviewed the following tasks:
TASK 05-11-05-200-801, dated March 4, 2021, from ESM 05-
11-05 Static Structures--Life Limits, of GE CF34-8C EM GEK105091, Rev
51, dated April 1, 2022;
TASK 05-11-05-200-801, dated March 4, 2021, from ESM 05-
11-05 Static Structures--Life Limits, of GE CF34-8E EM GEK112031, Rev
43, dated April 1, 2022; and
TASK 05-11-25-200-801, dated November 3, 2020, from ESM
05-11-25 Static Structures--BJ Life Limits, of GE CF34-8C EM GEK105091,
Rev 51, dated April 1, 2022.
These tasks, differentiated by GE CF34-8 turbofan engine model,
identify the combustion chamber assembly part number, life limit
cycles, and revised inspections.
The FAA also reviewed the following tasks:
TASK 05-21-03-200-801, dated April 1, 2019, from ESM 05-
21-03 Airworthiness Limitations--Mandatory Inspection 001, of GE CF34-
8C EM GEK105091, Rev 51, dated April 1, 2022; and
TASK 05-21-03-200-801, dated April 1, 2019, from ESM 05-
21-03 Airworthiness Limitations--Mandatory Inspection 001, of GE CF34-
8E EM GEK112031, Rev 43, dated April 1, 2022.
These tasks, differentiated by GE CF34-8 turbofan engine model,
describe revised inspection threshold limits and re-inspection interval
limits for the combustion chamber assembly.
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 ADDRESSES.

Proposed AD Requirements in This SNPRM

This proposed AD would require revisions to the ALS of the existing
EM and the operator's existing approved maintenance or inspection
program, as applicable, to incorporate initial and repetitive FPIs of
the combustion chamber assembly, except as discussed under
``Differences Between this proposed SNPRM and the Service
Information.''

Differences Between This SNPRM and the Service Information

TASK 05-21-03-200-801 of the GE CF34-8E EM GEK112031 and GE CF34-8C
EM GEK105091, both dated April 1, 2022, specify to perform the
inspection from the issuance date of the TR. This SNPRM would require
performing the inspection after the effective date of this AD.

Costs of Compliance

The FAA estimates that this proposed AD affects 1,633 GE CF34-8C
turbofan engine models and 857 GE CF34-8E turbofan engine models
installed on airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:

Estimated Costs

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: