Document ID: FAA-2020-0733-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2020-08-13T04:00Z

[Federal Register Volume 85, Number 157 (Thursday, August 13, 2020)]
[Proposed Rules]
[Pages 49322-49324]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-17594]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0733; Project Identifier AD-2020-00990-E]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain General Electric Company (GE) GE90-110B1 and GE90-115B 
model turbofan engines. This proposed 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 
proposed AD would require replacement of the affected HPT rotor stage 2 
disks and rotating CDP HPT seals. The FAA is proposing this AD to 
address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by September 
14, 2020.

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 https://www.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.
    For service information identified in this NPRM, contact General 
Electric Company, 1 Neumann Way, Cincinnati, OH 45215; phone: (513) 
552-3272; email: aviation.fleetsupport@ae.ge.com; 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.

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 NPRM, any comments received, and other information. The street 
address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Mehdi Lamnyi, Aerospace Engineer, ECO 
Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: (781) 
238-7743; fax: (781) 238-7999; email: Mehdi.Lamnyi@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 the ADDRESSES section. Include ``Docket No. FAA-2020-0733; 
Project Identifier AD-2020-00990-E'' 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 amend this NPRM because of those comments.
    The FAA has been informed that GE has communicated with affected 
operators regarding the proposed corrective action for this unsafe 
condition. As a result, affected operators are already aware of the 
proposed corrective action and, in some cases, have already performed 
the actions proposed in this AD. Therefore, the FAA has determined that 
a 30-day comment period is appropriate given the proposed short cyclic 
compliance period to correct the unsafe condition on the affected GE90 
model turbofan engines.
    Except for Confidential Business Information 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 
https://www.regulations.gov, including any

[[Page 49323]]

personal information you provide. The FAA will also post a report 
summarizing each substantive verbal contact received about this 
proposal.

Confidential Business Information

    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 NPRM 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 NPRM, 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 NPRM. Submissions containing 
CBI should be sent to Mehdi Lamnyi, Aerospace 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 was notified of the detection of melt-related freckles in 
the billet during the forging inspection of HPT disks, which may reduce 
the life limits of certain HPT rotor stage 2 disks and certain rotating 
CDP HPT seals. The inspection process in place at the time of 
production did not identify these freckles. The manufacturer determined 
the need to reduce the life limits of the affected HPT rotor stage 2 
disks and rotating CDP HPT seals. This AD requires removal of these 
affected parts before reaching their new life limits. This condition, 
if not addressed, could result in uncontained release of both the HPT 
rotor stage 2 disk and the rotating CDP HPT seal, damage to the engine, 
and damage to the aircraft.

FAA's Determination

    The FAA is proposing this AD because the agency has determined the 
unsafe condition described previously is likely to exist or develop in 
other products of the same type design.

Related Service Information

    The FAA reviewed GE Service Bulletin (SB) GE90-100 S/B 72-0845, 
Revision 01, dated July 17, 2020. The SB describes procedures for 
removal of the HPT rotor stage 2 disk and the rotating CDP HPT seal 
from service. 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 the ADDRESSES section.

Proposed AD Requirements

    This proposed AD would require replacement of certain HPT rotor 
stage 2 disks and certain rotating CDP HPT seals.

Interim Action

    The FAA considers this proposed 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, as proposed, would affect 1 engine 
installed on an airplane of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
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.
----------------------------------------------------------------------------------------------------------------

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

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.

[[Page 49324]]

Sec.  39.13   [Amended]

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

General Electric Company: Docket No. FAA-2020-0733; Project 
Identifier AD-2020-00990-E.

(a) Comments Due Date

    The FAA must receive comments by September 14, 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] TP13AU20.000

(h) Definition

    (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 to paragraph (g).
    (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)(1) of this AD. You may email your 
request to: ANE-AD-AMOC@faa.gov.
    (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

    (1) 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) 238-7999; 
email: Mehdi.Lamnyi@faa.gov.
    (2) For service information identified in this AD, contact 
General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: aviation.fleetsupport@ae.ge.com; 
website: www.ge.com. You may view this referenced 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.

    Issued on August 6, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-17594 Filed 8-12-20; 8:45 am]
BILLING CODE 4910-13-P