[Federal Register Volume 85, Number 110 (Monday, June 8, 2020)]
[Proposed Rules]
[Pages 35021-35024]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-12160]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0555; Project Identifier AD-2020-00615-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) GEnx-1B64/P2, -1B67/P2, -
1B70/P2, -1B70C/P2,-1B70/75/P2, -1B74/75/P2, -1B76/P2, -1B76A/P2, and 
GEnx-2B67/P 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 a certain stages 6-10 compressor rotor spool. This proposed 
AD would require the removal of certain HPT rotor stage 2 disk and the 
removal of a certain stages 6-10 compressor rotor spool before reaching 
their new life limits. 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 July 23, 
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, GE Aviation, Room 285, 1 Neumann Way, Cincinnati, OH 
45215; phone: 513-552-3272; email: [email protected]. 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-
0555; 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. Comments will be 
available in the AD docket shortly after receipt.

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: 

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-2020-0555; 
Project Identifier AD-2020-00615-E'' at the beginning of your comments. 
The FAA specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of this NPRM. The FAA will 
consider all comments received by the closing date and may amend this 
NPRM 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 
https://www.regulations.gov, including any personal information you 
provide. The FAA will also post a report summarizing each substantive 
verbal contact received about this NPRM.

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 AD 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 AD, 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 AD. 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.

Discussion

    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 a certain stages 
6-10 compressor rotor spool. 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 a certain stages 6-10 compressor rotor spool. This AD 
requires removal of these affected parts before reaching the new life 
limits. This condition, if not addressed, could result in uncontained 
release of both the HPT rotor stage 2 disk and the stages 6-10 
compressor rotor spool, damage to the engine, and damage to the 
aircraft.

Related Service Information

    The FAA reviewed GE GEnx-1B Service Bulletin (SB) 72-0473 R00, 
dated April 14, 2020; GE GEnx-1B SB 72-0474 R00, dated April 14, 2020; 
and GE GEnx-2B SB 72-0416 R00, dated April 14, 2020. GE GEnx-1B SB 72-
0473 R00 describes procedures for removing and replacing the HPT rotor 
stage 2 disks on GE GEnx-1B model engines. GE GEnx-1B SB 72-0474 R00 
describes procedures for removing and replacing the stages 6-10 
compressor

[[Page 35022]]

rotor spool on GE GEnx-1B model engines. GE GEnx-2B SB 72-0416 R00 
describes procedures for removing and replacing the HPT rotor stage 2 
disks on GE GEnx-2B model engines.

FAA's Determination

    The FAA is proposing this AD because the Agency evaluated all the 
relevant information and determined the unsafe condition described 
previously is likely to exist or develop in other products of the same 
type design.

Proposed AD Requirements

    This proposed AD would require the removal of certain HPT rotor 
stage 2 disk and the removal of a certain stages 6-10 compressor rotor 
spool before reaching their new life limits.

Interim Action

    The FAA considers this proposed AD interim action. The 
investigation into identifying the complete population of affected 
parts is on-going and the FAA will consider further rulemaking 
depending on the results of the investigation.

Costs of Compliance

    The FAA estimates that this proposed AD affects two engines 
installed on airplanes of U.S. registry; one engine requiring the HPT 
rotor stage 2 disk replacement and one engine requiring the stages 6-10 
compressor rotor spool replacement.
    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     1,500 work-hours x $85 per         $458,900        $586,400        $586,400
 stage 2 disk.                        hour = $127,500.
Remove and replace the stages 6-10   600 work-hours x $85 per          1,018,600       1,069,600       1,069,600
 compressor rotor spool.              hour = $51,000.
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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

    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.


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-2020-0555; Project 
Identifier AD-2020-00615-E.

(a) Comments Due Date

    The FAA must receive comments by July 23, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all General Electric Company (GE) GEnx-1B64/
P2, -1B67/P2, -1B70/P2, -1B70C/P2, -1B70/75/P2, -1B74/75/P2, -1B76/
P2, -1B76A/P2, and GEnx-2B67/P model turbofan engines with an engine 
serial number (S/N) listed in Figure 1 to paragraph (c) of this AD.

[[Page 35023]]

[GRAPHIC] [TIFF OMITTED] TP08JN20.001

(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 high-
pressure turbine (HPT) rotor stage 2 disks and a certain stages 6-10 
compressor rotor spool. The FAA is issuing this AD to prevent 
failure of the HPT rotor stage 2 disk and stages 6-10 compressor 
rotor spool. The unsafe condition, if not addressed, could result in 
uncontained release of both the HPT rotor stage 2 disk and the 
stages 6-10 compressor rotor spool, 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

    After the effective date of this AD, before the parts accumulate 
the cycles since new (CSN) threshold listed in Table 1 to paragraph 
(g) of this AD, remove the affected HPT rotor stage 2 disk and the 
stages 6-10 compressor rotor spool from service and replace with 
parts eligible for installation. 
[GRAPHIC] [TIFF OMITTED] TP08JN20.002


[[Page 35024]]



(h) Installation Prohibition

    After the effective date of this AD, do not install the affected 
HPT rotor stage 2 disks or the stages 6-10 compressor rotor spool 
identified in Table 1 to paragraph (g) of this AD on an engine.

(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: [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

    (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: 781-238-7199; email: 
[email protected].
    (2) For service information identified in this AD, contact 
General Electric Company, GE Aviation, Room 285, 1 Neumann Way, 
Cincinnati, OH 45215; phone: 513-552-3272; email: 
[email protected]. 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 June 1, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-12160 Filed 6-5-20; 8:45 am]
 BILLING CODE 4910-13-P