Document ID: FAA-2021-0869-0003
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2021-12-21T05:00Z

[Federal Register Volume 86, Number 242 (Tuesday, December 21, 2021)]
[Rules and Regulations]
[Pages 72178-72181]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-27480]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0869; Project Identifier AD-2021-00176-E; 
Amendment 39-21878; AD 2021-26-19]
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 
certain General Electric Company (GE) CF34-8C and CF34-8E model 
turbofan engines. This AD was prompted by a report of a quality escape 
during the manufacturing of a high-pressure turbine (HPT) rotor stage 1 
disk. This AD requires removing the HPT rotor stage 1 disk from service 
and replacing the HPT rotor stage 1 disk with a part eligible for 
installation. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective January 25, 2022.

ADDRESSES: For service information identified in this final rule, 
contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: [email protected]; website: 
https://www.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. It is 
also available at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2021-0869.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0869; 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 U.S. Department of Transportation, Docket Operations, M-30, 
West Building, Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Scott Stevenson, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7132; fax: (781) 238-7199; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain GE CF34-8C5, 
CF34-8C5B1, CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, 
CF34-8E6, and CF34-8E6A1 model turbofan engines. The NPRM published in 
the Federal Register on October 8, 2021 (86 FR 56217). The NPRM was 
prompted by GE notifying the FAA of a quality escape that occurred 
during the manufacturing of an HPT rotor stage 1 disk. The quality 
escape occurred at a supplier that began production in August 2019. On 
November 25, 2019, the supplier discovered tool gouges at the forward 
chamfer on the air holes of an HPT rotor stage 1 disk. These gouges may 
reduce the life of the HPT rotor stage 1 disk. In the NPRM, the FAA 
proposed to require removing a certain HPT rotor stage 1 disk from 
service and replacing the HPT rotor stage 1 disk with a part eligible 
for installation. The FAA is issuing this AD to address the unsafe 
condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received a comment from one commenter, the Air Line Pilots 
Association (ALPA). ALPA supported the NPRM without change.

Conclusion

    The FAA reviewed the relevant data, considered the comment 
received, and determined that air safety requires adopting the AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. This AD is adopted as proposed in the 
NPRM.

Related Service Information

    The FAA reviewed GE CF34-8C Alert Service Bulletin (ASB) 72-A0344 
R01 and GE CF34-8E ASB 72-A0228 R01, both dated December 19, 2019. The 
ASBs describe procedures for removing the HPT rotor stage 1 disk. The 
FAA also reviewed GE Repair Document RD #150-1811-P1, dated March 17, 
2020. This document describes procedures for repairing the HPT rotor 
stage 1 disk.

Costs of Compliance

    The FAA estimates that this AD affects 23 engines installed on 
airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

[[Page 72179]]

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Remove and replace HPT rotor stage 1    812 work-hours x $85 per        $258,100        $327,120      $7,523,760
 disk.                                   hour = $69,020.
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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:

2021-26-19 General Electric Company: Amendment 39-21878; Docket No. 
FAA-2021-0869; Project Identifier AD-2021-00176-E.

(a) Effective Date

    This airworthiness directive (AD) is effective January 25, 2022.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) CF34-8C5, CF34-
8C5B1, CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-
8E6, and CF34-8E6A1 model turbofan engines with an installed high-
pressure turbine (HPT) rotor stage 1 disk, part number (P/N) 
4125T22P04, and a serial number (S/N) listed in Figure 1 or Figure 2 
to paragraph (c) of this AD.
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[GRAPHIC] [TIFF OMITTED] TR21DE21.008

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine 
Section.

(e) Unsafe Condition

    This AD was prompted by a report of a quality escape during the 
manufacturing of an HPT rotor stage 1 disk. The FAA is issuing this 
AD to prevent failure of the HPT rotor stage 1 disk. The unsafe 
condition, if not addressed, could result in uncontained disk 
release, 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

    For all affected engines, at the next engine shop visit or 
before the HPT rotor stage 1 disk accumulates 7,600 cycles since 
new, whichever occurs first after the effective date of this AD, 
remove the HPT rotor stage 1 disk from service and replace with a 
part eligible for installation.

(h) Definitions

    For the purpose of this AD:
    (1) An ``engine shop visit'' is the induction of an engine into 
the shop for maintenance involving the separation of pairs of major 
mating engine flanges, except that the separation of engine flanges 
solely for the

[[Page 72181]]

purposes of transportation without subsequent engine maintenance 
does not constitute an engine shop visit.
    (2) A ``part eligible for installation'' is an HPT rotor stage 1 
disk that is not listed in Figure 1 or Figure 2 to paragraph (c) of 
this AD or an HPT rotor stage 1 disk that has been repaired using an 
FAA-approved repair.
    Note 1 to paragraph (h)(2): Guidance for repairing the HPT rotor 
stage 1 disk can be found in GE Repair Document RD #150-1811-P1, 
dated March 17, 2020.

(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. Information may be emailed 
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; fax: (781) 238-7199; 
email: [email protected].

(k) Material Incorporated by Reference

    None.

    Issued on December 15, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-27480 Filed 12-20-21; 8:45 am]
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