Document ID: FAA-2020-0592-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2020-06-12T04:00Z

[Federal Register Volume 85, Number 114 (Friday, June 12, 2020)]
[Proposed Rules]
[Pages 35816-35818]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-12650]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0592; Project Identifier AD-2020-00251-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 all General Electric Company (GE) GEnx-1B64/P2, GEnx-1B67/P2, GEnx-
1B70/75/P2, GEnx-1B70/P2, GEnx-1B70C/P2, GEnx-1B74/75/P2, GEnx-1B76/P2, 
GEnx-1B76A/P2, and GEnx-2B67/P model turbofan engines with a certain a 
high-pressure turbine (HPT) rotor stage 2 disk installed. This proposed 
AD was prompted by a report of the potential for undetected subsurface 
anomalies formed during the manufacturing process that could result in 
uncontained failure of the HPT rotor stage 2 disk. This proposed AD 
would require an immersion ultrasonic inspection (USI) of the HPT rotor 
stage 2 disk and, depending on the results of the inspection, 
replacement of the HPT rotor stage 2 disk with a part eligible for 
installation. 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 27, 
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: aviation.fleetsupport@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-
0592; 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: 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-2020-0592; 
Project Identifier AD-2020-00251-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 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 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.

Discussion

    The FAA received a report of the potential for undetected 
subsurface anomalies formed during the manufacturing process that could 
result in uncontained failure of the HPT rotor stage 2 disk. During an 
investigation by GE into melt-related material anomalies, a subsurface 
anomaly was found in an early production HPT rotor stage 2 disk. This 
type of subsurface anomaly has the potential to cause the failure of 
the HPT rotor stage 2 disk. In response, GE published service 
information that introduces inspections to prevent failure of the HPT 
rotor stage 2 disk. This condition, if not addressed, could result in 
uncontained HPT rotor stage 2 disk release, damage to the engine, and 
damage to the airplane.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed GE GEnx-1B Service Bulletin (SB) 72-0463 R01, 
dated January 6, 2020, and GE GEnx-2B SB 72-0402 R01, dated January 8, 
2020. The service information describes procedures for performing an 
immersion

[[Page 35817]]

USI of the affected HPT rotor stage 2 disks on GEnx-1B and GEnx-2B 
model turbofan engines. 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.

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 an immersion USI of the HPT rotor 
stage 2 disk and, depending on the results of the inspection, 
replacement of the HPT rotor stage 2 disk with a part eligible for 
installation.

Costs of Compliance

    The FAA estimates that this proposed AD affects 276 engines 
installed on airplanes 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
----------------------------------------------------------------------------------------------------------------
USI of HPT rotor stage 2 disk.......  8 work-hours x $85 per               $0             $680         $187,680
                                       hour = $680.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
proposed inspection. The FAA has no way of determining the number of 
aircraft that might need this replacement:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Remove and replace the HPT rotor stage 2 disk  2 work-hours x $85 per hour =          $458,900         $459,070
                                                $170.
----------------------------------------------------------------------------------------------------------------

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-2020-0592; Project 
Identifier AD-2020-00251-E.

(a) Comments Due Date

    The FAA must receive comments by July 27, 2020.

(b) Affected ADs

    None.

(c) Applicability

    (1) This AD applies to all General Electric Company (GE) GEnx-
1B64/P2, GEnx-1B67/P2, GEnx-1B70/75/P2, GEnx-1B70/P2, GEnx-1B70C/P2, 
GEnx-1B74/75/P2, GEnx-1B76/P2, and GEnx-1B76A/P2 model turbofan 
engines that have a high-pressure turbine (HPT) rotor stage 2 disk, 
part number (P/N) 2383M86P02, and a serial number (S/N) listed in 
paragraph 4, Appendix--A, Table 1, Table 2, or Table 3, of GE GEnx-
1B Service Bulletin (SB) 72-0463 R01, dated January 6, 2020, 
installed.
    (2) This AD applies to all GE GEnx-2B67/P model turbofan engines 
that have a HPT rotor stage 2 disk, P/N 2383M86P02, and a S/N listed 
in paragraph 4, Appendix--A, Table 1, Table 2, or Table 3, of GE 
GEnx-2B SB 72-0402 R01, dated January 8, 2020, installed.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a report of the potential for undetected 
subsurface anomalies formed during the manufacturing process that 
could result in uncontained failure of the HPT rotor stage 2 disk. 
The FAA is issuing this AD to prevent failure of the HPT rotor stage 
2 disk. The unsafe condition, if not addressed, could result in

[[Page 35818]]

uncontained HPT rotor stage 2 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

    (1) For affected GE GEnx-1B engines, at the next engine shop 
visit after the effective date of this AD, or before the HPT rotor 
stage 2 disk has accumulated 6,500 cycles since new (CSN), whichever 
occurs first, perform an immersion ultrasonic inspection (USI) of 
the HPT rotor stage 2 disk using paragraph 3.B.(1) of GE GEnx-1B SB 
72-0463 R01, dated January 6, 2020.
    (2) If, during the USI required by paragraph (g)(1) of this AD, 
a rejectable indication is found, before further flight, remove the 
HPT rotor stage 2 disk from service and replace it with a part 
eligible for installation.
    (3) For affected GE GEnx-2B engines, at the next engine shop 
visit after the effective date of this AD, or before the HPT rotor 
stage 2 disk has accumulated 6,500 CSN, whichever occurs first, 
perform an immersion USI of the HPT rotor stage 2 disk using 
paragraph 3.B.(1) of GE GEnx-2B SB 72-0402 R01, dated January 8, 
2020.
    (4) If, during the USI required by paragraph (g)(3) of this AD, 
a rejectable indication is found, before further flight, remove the 
HPT rotor stage 2 disk from service and replace it with a part 
eligible for installation.

(h) Definitions

    (1) For the purpose of this AD, an engine shop visit is when a 
major engine flange is separated for purposes other than the removal 
of the fan for transportation.
    (2) For the purposes of this AD, a ``part eligible for 
installation'' is:
    (i) An HPT rotor stage 2 disk, which is not a S/N listed in 
paragraph 4, Appendix--A, Table 1, Table 2, or Table 3, of GE GEnx-
1B SB 72-0463 R01, dated January 6, 2020, or GE GEnx-2B SB 72-0402 
R01, dated January 8, 2020; or,
    (ii) An HPT rotor stage 2 disk that has successfully passed the 
immersion USI required by paragraph (g)(1) or (3) of this AD, or 
passed the immersion USI using GE GEnx-1B SB 72-0463 R00, dated 
November 20, 2019, or GE GEnx-2B SB 72-0402 R00, dated November 20, 
2019, before the effective date of this AD.

(i) Credit for Previous Actions

    You may take credit for the immersion USI of the HPT rotor stage 
2 disk required by paragraph (g)(1) or (3) of this AD if you 
performed the inspection before the effective date of this AD using 
GE GEnx-1B SB 72-0463 R00, dated November 20, 2019, or GE GEnx-2B SB 
72-0402 R00, dated November 20, 2019.

(j) 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 (k)(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.

(k) 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: 
Mehdi.Lamnyi@faa.gov.
    (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: 
aviation.fleetsupport@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 June 8, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-12650 Filed 6-11-20; 8:45 am]
BILLING CODE 4910-13-P