Airworthiness Directives; General Electric Company Turbofan Engines

[Federal Register Volume 85, Number 198 (Tuesday, October 13, 2020)]
[Rules and Regulations]
[Pages 64375-64377]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-22505]



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Federal Register / Vol. 85, No. 198 / Tuesday, October 13, 2020 / 
Rules and Regulations

[[Page 64375]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0733; Project Identifier AD-2020-00990-E; 
Amendment 39-21286; AD 2020-21-13]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain General Electric Company (GE) GE90-110B1 and GE90-115B model 
turbofan engines. This AD was prompted by the detection of melt-related 
freckles in the billet, which may reduce the life limits of certain 
high-pressure turbine (HPT) rotor stage 2 disks and certain rotating 
compressor discharge pressure (CDP) HPT seals. This AD requires the 
replacement of the affected HPT rotor stage 2 disks and rotating CDP 
HPT seals. The FAA is issuing this AD to address the unsafe condition 
on these products.

DATES: This AD is effective November 17, 2020.

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: 
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 781-238-7759. It is also 
available on the internet at https://www.regulations.gov by searching 
for and locating Docket No. FAA-2020-0733.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-
0733; 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.

FOR FURTHER INFORMATION CONTACT: Mehdi Lamnyi, Aerospace Engineer, ECO 
Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-
238-7743; fax: 781-238-7199; email: [email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    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 GE90-110B1 
and GE90-115B model turbofan engines. The NPRM published in the Federal 
Register on August 13, 2020 (85 FR 49322). The NPRM was prompted by the 
detection of melt-related freckles in the billet, which may reduce the 
life limits of certain HPT rotor stage 2 disks and certain rotating CDP 
HPT seals. The NPRM proposed to require the replacement of certain HPT 
rotor stage 2 disks and certain rotating CDP HPT seals. The FAA is 
issuing this AD to address the unsafe condition on these products.

Comments

    The FAA gave the public the opportunity to participate in 
developing this final rule. The FAA has considered the comments 
received. Boeing Commercial Airplanes supported the NPRM. The Air Line 
Pilots Association and United Airlines reviewed the NPRM and have no 
objections.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety and the public interest 
require adopting this final rule as proposed.

Related Service Information

    The FAA reviewed GE Service Bulletin GE90-100 S/B 72-0845, Revision 
1, dated July 17, 2020. The service information describes procedures 
for the removal of affected HPT rotor stage 2 disks and rotating CDP 
HPT seals from service.

Interim Action

    The FAA considers this AD an interim action. This issue is still 
under investigation by the manufacturer and, depending on the results 
of that investigation, the FAA may consider further rulemaking action.

Costs of Compliance

    The FAA estimates that this AD will affect 1 engine installed on an 
airplane 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
----------------------------------------------------------------------------------------------------------------
Remove and replace the HPT rotor stage  1,500 work-hours x $85          $565,600        $693,100        $693,100
 2 disk.                                 per hour = $127,500.
Remove and replace the rotating CDP     600 work-hours x $85 per         209,900         260,900               0
 HPT Seal.                               hour = $51,000.
----------------------------------------------------------------------------------------------------------------


[[Page 64376]]

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 (AD):

2020-21-13 General Electric Company: Amendment 39-21286; Docket No. 
FAA-2020-0733; Project Identifier AD-2020-00990-E.

(a) Effective Date

    This AD is effective November 17, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company GE90-110B1 and GE90-
115B model turbofan engines with:
    (1) A high-pressure turbine (HPT) rotor stage 2 disk, part 
number (P/N) 2505M73P03, and serial number (S/N) TMT1BA38 or 
TMT1BA41, installed; or
    (2) A rotating compressor discharge pressure (CDP) HPT seal, P/N 
2479M03P01, and S/N GEE1H7GH or GEE1H7JJ, installed.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by the detection of melt-related freckles 
in the billet, which may reduce the life limits of certain HPT rotor 
stage 2 disks and certain rotating CDP HPT seals. The FAA is issuing 
this AD to prevent uncontained release of both the HPT rotor stage 2 
disk and the rotating CDP HPT seal. The unsafe condition, if not 
addressed, could result in damage to the engine and damage to the 
aircraft.

(f) Compliance

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

(g) Required Actions

    (1) Before the affected HPT rotor stage 2 disk or the rotating 
CDP HPT seal listed in Table 1 to paragraph (g) of this AD (``Table 
1'') accumulates the cycles since new (CSN) threshold in Table 1, or 
at the next engine shop visit, whichever occurs first after the 
effective date of this AD, remove the affected part from service and 
replace it with a part eligible for installation.
    (2) If the affected HPT rotor stage 2 disk or rotating CDP HPT 
seal has already exceeded the CSN threshold in Table 1, remove the 
affected part before further flight and replace with a part eligible 
for installation.
[GRAPHIC] [TIFF OMITTED] TR13OC20.005

(h) Definitions

    (1) For the purpose of this AD, a part eligible for installation 
is any HPT stage 2 disk or rotating CDP HPT seal with an S/N that is 
not listed in Table 1.
    (2) For the purpose of this AD, 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 purposes of 
transportation of the engine without subsequent engine maintenance 
does not constitute an engine shop visit.

(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. You may email your request 
to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager

[[Page 64377]]

of the local flight standards district office/certificate holding 
district office.

(j) Related Information

    For more information about this AD, contact Mehdi Lamnyi, 
Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: 781-238-7743; fax: 781-238-7199; email: 
[email protected].

(k) Material Incorporated by Reference

    None.

    Issued on October 6, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-22505 Filed 10-9-20; 8:45 am]
BILLING CODE 4910-13-P

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