Airworthiness Directives; General Electric Company Turbofan Engines

[Federal Register Volume 88, Number 25 (Tuesday, February 7, 2023)]
[Rules and Regulations]
[Pages 7859-7862]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-02512]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0766; Project Identifier 2019-NE-23-AD; Amendment 
39-22312; AD 2023-02-05]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 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 AD was prompted by a predicted reduction in the cyclic life of the 
combustion chamber assembly aft flange. This AD requires revisions to 
the airworthiness limitations section (ALS) of the existing engine 
manual (EM) and the operator's existing approved maintenance or 
inspection program, as applicable, to incorporate initial and 
repetitive fluorescent penetrant inspections (FPIs) of the combustion 
chamber assembly. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective March 14, 2023.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of March 14, 
2023.

ADDRESSES: 
    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 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:
    <bullet> For GE service information identified in this final rule, 
contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: ge.com">aviation.fleetsupport@ge.com; website: 
ge.com.
    <bullet> 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. It is 
also available at regulations.gov by searching for and locating Docket 
No. FAA-2019-0766.

FOR FURTHER INFORMATION CONTACT: Scott Stevenson, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7132; email: [email protected].

[[Page 7860]]


SUPPLEMENTARY INFORMATION: 

Background

    The FAA issued a supplemental notice of proposed rulemaking (SNPRM) 
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-C5A2, 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 the 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 SNPRM published in the Federal Register on October 07, 
2022 (87 FR 60944). The SNPRM was prompted by a predicted reduction in 
the cyclic life of the combustion chamber assembly aft flange. As a 
result, the manufacturer incorporated temporary revisions (TRs) into 
the GE CF34-8C and GE CF34-8E EMs for a scheduled maintenance check. In 
the SNPRM, the FAA proposed to 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. The FAA is issuing 
this AD to address the unsafe condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from three commenters. The commenters 
were Horizon Air, Japan Airlines (JAL), and SkyWest Airlines (SkyWest). 
The following presents the comments received on the SNPRM and the FAA's 
response to each comment.

Request To Replace ``ESM'' Reference With ``EM'' Reference

    Horizon Air requested that the FAA replace all references of 
``ESM'' with ``EM'' in this final rule. Horizon Air reasoned that the 
SNPRM only defines the acronym ``EM,'' and both acronyms are used 
interchangeably in the SNPRM.
    The FAA clarifies that the reference to ``ESM'' is not an acronym 
defined by the FAA in the proposed AD and used interchangeably with 
``EM.'' ``ESM'' is part of GE's chapter title within each task 
reference and must be used for an accurate reference. The FAA did not 
change this AD as a result of this comment.

Request To Add the Date of the Task in Paragraph (g)(3)

    Horizon Air requested that the FAA include the task revision date 
for ``TASK 05-21-03-200-801,'' referenced in paragraph (g)(3)(ii) of 
the SNPRM. Horizon Air reasoned that adding the task revision date 
would make the wording consistent with the dates of the tasks in 
paragraphs (g)(1)(ii) and (2)(ii) of the SNPRM.
    The FAA established a shorthand notation in paragraph (g)(2)(ii) of 
the SNPRM, which contains the full citation, including the task 
revision date, followed by the shorthand notation ``TASK 05-21-03-200-
801.'' The FAA then used the established shorthand notation to 
reference the task in paragraph (g)(3)(ii) of the SNPRM. The FAA did 
not change this AD as a result of this comment.

Request To Revise Paragraph (g)(1)(ii), (2)(ii), and (3)(ii) of the AD

    Horizon Air requested that the FAA revise paragraphs (g)(1)(ii), 
(2)(ii), and (3)(ii) of the AD, as those paragraphs do not clearly 
include that performance of the inspection within 2,200 cycles from the 
effective date of this AD is only applicable to those combustion 
chamber assemblies that have exceeded the inspection threshold 
specified in the tables referenced in TASK 05-21-03-200-801. Similarly, 
JAL requested that the FAA revise paragraph (g)(1)(ii) for the same 
reasons articulated by Horizon Air.
    In response to these comments, the FAA has revised the language in 
paragraphs (g)(1)(ii), (2)(ii), and (3)(ii) of this AD to clarify that 
where the notes to Tables 801, 802, 803, 804, and 805, included in TASK 
05-21-03-200-801, specify to perform the inspection within 2,200 cycles 
from the issuance date of the TR, this AD requires performing the 
inspection within 2,200 cycles from the effective date of this AD. The 
FAA further clarifies that the notes are part of the task, and 
therefore, has removed ``including the notes.''

Request To Correct an Incorrect Reference to a Task in Paragraph 
(g)(2)(i)

    SkyWest requested that the FAA correct an incorrect reference in 
paragraph (g)(2)(i) of this AD. SkyWest noted that Table 802 does not 
exist in TASK 05-11-25-200-801, which is specific to GE CF34-8C5 model 
turbofan engines with/B minor model designation.
    In response to this comment, the FAA has revised paragraph 
(g)(2)(i) of this AD from ``Table 801 in TASK 05-11-05-200-801 and 
Table 802 in TASK 05-11-25-200-801, dated November 3, 2020, from ESM 
05-11-25 Static Structures--BJ Life Limits (TASK 05-11-25-200-801)'' to 
``Tables 801 (for -8C1) and 802 (for -8C5) in TASK 05-11-05-200-801, 
dated March 4, 2021, from ESM 05-11-05 Static Structures--Life Limits 
(TASK 05-11-05-200-801).''

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 SNPRM. 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 tasks:
    <bullet> 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;
    <bullet> 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
    <bullet> 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:
    <bullet> 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
    <bullet> 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

[[Page 7861]]

have access to it through their normal course of business or by the 
means identified in ADDRESSES.

Costs of Compliance

    The FAA estimates that this 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 AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Revise the ALS of the EM and            1 work-hour x $85 per                 $0             $85        $211,650
 operator's existing approved            hour = $85.
 maintenance or inspection program (GE
 CF34-8C and CF34-8E).
----------------------------------------------------------------------------------------------------------------

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

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2023-02-05 General Electric Company: Amendment 39-22312; Docket No. 
FAA-2019-0766; Project Identifier 2019-NE-23-AD.

(a) Effective Date

    This airworthiness directive (AD) is effective March 14, 2023.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to 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, 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.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7240, Turbine Engine 
Combustion Section.

(e) Unsafe Condition

    This AD was prompted by a predicted reduction in the cyclic life 
of the combustion chamber assembly aft flange. The FAA is issuing 
this AD to prevent failure of the combustion chamber assembly. The 
unsafe condition, if not addressed, could result in combustion 
chamber assemblies failing before reaching their published life 
limit, uncontained release of the combustion chamber assembly, 
damage to the engine, and damage to the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    Within 90 days after the effective date of this AD, revise the 
airworthiness limitations section (ALS) of the existing engine 
manual (EM) and the operator's existing approved maintenance or 
inspection program, as applicable, to incorporate the following 
requirements for fluorescent penetrant inspections of the combustion 
chamber assembly aft flange.
    (1) For combustion chamber assemblies with part numbers (P/Ns) 
4145T11G08, 4145T11G09, 4180T27G01, or 4180T27G03 installed on GE 
CF34-8E model turbofan engines:
    (i) Replace Table 801, Static Structures--Life Limits (Table 
801), with the revised Table 801 in TASK 05-11-05-200-801, dated 
March 4, 2021, from ESM 05-11-05 Static Structures--Life Limits 
(TASK 05-11-05-200-801), of GE CF34-8E EM GEK112031, Rev 43, dated 
April 1, 2022 (GE CF34-8E EM GEK112031), and
    (ii) Add TASK 05-21-03-200-801, dated April 1, 2019, from ESM 
05-21-03 Airworthiness Limitations--Mandatory Inspection 001 (TASK 
05-21-03-200-801), of GE CF34-8E EM GEK112031. Where the notes to 
Tables 801 and 802, included in TASK 05-21-03-200-801 of GE CF34-8E 
EM GEK112031, specify to perform the inspection within 2,200 cycles 
from the issuance date of the temporary revision (TR), this AD 
requires performing the inspection within 2,200 cycles from the 
effective date of this AD.
    (2) For combustion chamber assemblies with P/Ns 4126T87G04, 
4126T87G05, 4126T87G07, 4126T87G08, 4180T27G04, 4923T82G01, or 
4923T82G02 installed on GE CF34-8C1 model turbofan engines, or with 
P/Ns 4145T11G08, 4145T11G10, 4180T27G02, 4180T27G04, or 4923T82G02 
installed on GE CF34-8C5, CF34-8C5/M, CF34-8C5A1, CF34-8C5A1/M, 
CF34-8C5A2, CF34-8C5A2/M, CF34-8C5A3, or CF34-8C5B1 model turbofan 
engines:
    (i) Replace Tables 801 (for -8C1) and 802 (for -8C5) Static 
Structures--Life Limits (Table 801 and Table 802), with the revised 
Tables 801 and 802 in TASK 05-11-05-200-801, dated March 4, 2021, 
from ESM 05-11-

[[Page 7862]]

05 Static Structures--Life Limits (TASK 05-11-05-200-801), of GE 
CF34-8C EM GEK105091, Rev 51, dated April 1, 2022 (GE CF34-8C EM 
GEK105091); and
    (ii) Add TASK 05-21-03-200-801, dated April 1, 2019, from ESM 
05-21-03 Airworthiness Limitations--Mandatory Inspection 001 (TASK 
05-21-03-200-801), of GE CF34-8C EM GEK105091. Where the notes to 
Tables 801, 802, 803, 804, and 805, included in TASK 05-21-03-200-
801 of GE CF34-8C EM GEK105091, specify to perform the inspection 
within 2,200 cycles from the issuance date of the TR, this AD 
requires performing the inspection within 2,200 cycles from the 
effective date of this AD.
    (3) For combustion chamber assemblies with P/Ns 4145T11G08, 
4145T11G10, 4180T27G02, 4180T27G04, or 4923T82G02 installed on GE 
CF34-8C5B1/B, CF34-8C5/B, CF34-8C5A1/B, or CF34-8C5A2/B model 
turbofan engines:
    (i) Replace Table 801 (for/B -8C5) Static Structures--Life 
Limits with the revised Table 801 in TASK 05-11-25-200-801, of GE 
CF34-8C EM GEK105091; and
    (ii) Add TASK-05-21-03-200-801, of GE CF34-8C EM GEK105091. 
Where the notes to Tables 801, 802, 803, 804, and 805, included in 
TASK 05-21-03-200-801 of GE CF34-8C EM GEK105091, specify to perform 
the inspection within 2,200 cycles from the issuance date of the TR, 
this AD requires performing the inspection within 2,200 cycles from 
the effective date of this AD.
    (4) After performing the actions required by paragraphs (g)(1) 
through (3) of this AD, except as provided in paragraph (i) of this 
AD, no alternative life limits may be approved.

(h) Credit for Previous Actions

    You may take credit for revising the ALS of the existing EM and 
the operator's existing approved maintenance or inspection program, 
as applicable, required by paragraphs (g)(1) through (3) of this AD 
if the actions were completed before the effective date of this AD 
using 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; 
or GE CF34-8C TR 05-0142, dated February 13, 2019.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, ECO Branch, FAA, has the authority to approve 
AMOCs for this AD, if requested using the procedures found in 14 CFR 
39.19. In accordance with 14 CFR 39.19, send your request to your 
principal inspector or local Flight Standards District Office, as 
appropriate. If sending information directly to the manager of the 
certification office, send it to the attention of the person 
identified in paragraph (j) of this AD and email it to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(j) Related Information

    For more information about this AD, contact Scott Stevenson, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781) 238-7132; email: 
[email protected].

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) 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.
    (ii) 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.
    (iii) 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.
    (iv) 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.
    (v) 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.
    (3) For GE service information identified in this AD, contact 
General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: ge.com">aviation.fleetsupport@ge.com; website: 
ge.com.
    (4) You may view this service information at 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on January 19, 2023.
Ross Landes,
Deputy Director for Regulatory Operations, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2023-02512 Filed 2-6-23; 8:45 am]
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