Document ID: FAA-2020-0850-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2020-09-24T04:00Z

[Federal Register Volume 85, Number 186 (Thursday, September 24, 2020)]
[Proposed Rules]
[Pages 60103-60107]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-20947]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0850; Project Identifier AD-2020-00288-E]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain GEnx-1B64, 1B64/P1, -1B64/P2, -1B67, -1B67/P1, -1B67/P2, -
1B70, -1B70/75/P1, -1B70/75/P2, -1B70/P1, -1B70/P2, -1B70C/P1, -1B70C/
P2, -1B74/75/P1, -1B74/75/P2, -1B76/P2, -1B76A/P2, -2B67, -2B67/P, and 
-2B67B model turbofan engines. This proposed AD was prompted by a 
finding during an inspection by the manufacturer that two stages 6-10 
compressor rotor spools in the high-pressure compressor (HPC) assembly 
were damaged at similar locations. Additionally, the manufacturer 
reported that certain stages 6-10 compressor rotor spool webs did not 
undergo a required fluorescent penetrant inspection (FPI) during 
production. This proposed AD would require inspection of the stages 6-
10 compressor rotor spool and, depending on the result of the 
inspection, replacement of the stages 6-10 compressor rotor spool 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 November 9, 
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,

[[Page 60104]]

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-
0850; 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) 238-7199; 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-2020-0850; 
Project Identifier AD-2020-00288-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.
    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 proposed AD.

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 received a report from the manufacturer that an inspection 
had found two stages 6-10 compressor rotor spools in the HPC assembly 
damaged at similar locations on the webs. The subsequent investigation 
determined that tool marks were created during the manufacturing 
process. In addition, the manufacturer also reported that certain 
stages 6-10 compressor rotor spool webs did not undergo a required FPI 
during production. This condition, if not addressed, could result in 
failure of the compressor rotor spool, uncontained release of debris, 
damage to the engine, and damage to the airplane.

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.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed GE GEnx-1B Service Bulletin (SB) 72-0472 R01, 
dated July 24, 2020 (``GEnx-1B SB 72-0472'') and GE GEnx-2B SB 72-0415 
R01, dated July 24, 2020 (``GEnx-2B SB 72-0415'').
    GEnx-1B SB 72-0472 describes procedures for performing a borescope 
inspection (BSI) or an eddy current inspection (ECI) of stage 6, stage 
7, and stage 8 webs, web transitions, and bore faces of the stages 6-10 
compressor rotor spool for GEnx-1B model turbofan engines. GEnx-1B SB 
72-0472 also provides the affected part and serial numbers of the 
stages 6-10 compressor rotor spools installed on GEnx-1B model turbofan 
engines.
    GEnx-2B SB 72-0415 describes procedures for performing a BSI or an 
ECI of stage 6, stage 7, and stage 8 webs, web transitions, and bore 
faces of the stages 6-10 compressor rotor spool for GEnx-2B model 
turbofan engines. GEnx-2B SB 72-0415 also provides the affected part 
and serial numbers of the stages 6-10 compressor rotor spools installed 
on 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.

Other Related Service Information

    The FAA also reviewed Subtask 72-31-45-160-002 of TASK 72-31-45-
200-807 in GE GEnx-1B Engine Manual 05-21-00, Life Limits 001 Mandatory 
Inspections, Rev. 31 dated, January 31, 2020; and Subtask 72-31-45-160-
002 of TASK 72-31-45-200-801 in GE GEnx-2B Engine Manual 05-21-00, Life 
Limits 001 Mandatory Inspections, Rev. 24 dated, January 31, 2020. The 
Subtasks provide guidance on performing the ECI on the stages 6-10 
compressor rotor spool on GE GEnx-1B and GEnx-2B model turbofan 
engines.
    The FAA also reviewed the following GE SBs: GEnx-1B SB 72-0448 R00, 
dated July 29, 2019 (``GEnx-1B SB 72-0448''); GEnx-1B SB 72-0460 R00, 
dated October 30, 2019 (``GEnx-1B SB 72-0460''); GEnx-2B SB 72-0385 
R02, dated July 29, 2019 (``GEnx-2B SB 72-0385''); and GEnx-2B SB 72-
0398 R00, dated October 30, 2019 (``GEnx-2B SB 72-0398'').
    GEnx-1B SB 72-0448 describes procedures for performing a BSI or an 
ECI of the stage 8 aft web of the HPC stages 6-10 rotor spool for GEnx-
1B model turbofan engines. GEnx-1B SB 72-0460 describes procedures for 
performing a BSI or an ECI of the stage 6 and stage 7 aft web of the 
HPC stages 6-10 rotor spool for GEnx-1B model turbofan engines.
    GEnx-2B SB 72-0385 describes procedures for performing a BSI or an 
ECI of the stage 8 aft web of the HPC stages 6-10 spool for GEnx-2B 
model turbofan engines. GEnx-2B SB 72-0398 describes procedures for 
performing a BSI or an ECI of the stage 6 and stage 7 aft web of the 
HPC stages 6-10 rotor spool for GEnx-2B model turbofan engines.

Proposed AD Requirements in This NPRM

    This proposed AD would require inspection of the stages 6-10 
compressor rotor spool. Certain affected GEnx-1B or GEnx-2B model 
turbofan engines, identified in paragraphs (g)(1)(i) and (g)(1)(ii) of 
this proposed

[[Page 60105]]

AD, have already completed acceptable inspections of the aft web of 
stage 6, stage 7, and stage 8 of the stages 6-10 compressor rotor 
spool. This proposed AD would require those affected engines to 
complete the inspection of the stages 6-10 compressor rotor spool by 
the next engine shop visit. All other affected GEnx-1B or GEnx-2B model 
turbofan engines would be required to complete inspection of the stages 
6-10 compressor rotor spool before exceeding the compliance times in 
Table 1 to paragraph (g)(1) of this AD. Depending on the results of the 
inspection, this AD would require replacement of the stages 6-10 
compressor rotor spool with a part eligible for installation.

Costs of Compliance

    The FAA estimates that this AD, as proposed, would affect 268 
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
----------------------------------------------------------------------------------------------------------------
BSI of GEnx-1B stage 6, stage 7, and    6 work-hours x $85 per                $0            $510         $89,760
 stage 8 aft webs, web transitions and   hour = $510.
 bore faces of the stages 6-10
 compressor rotor spool.
BSI of GEnx-2B stage 6, stage 7, and    6 work-hours x $85 per                 0             510          46,920
 stage 8 aft webs, web transitions and   hour = $510.
 bore faces of the stages 6-10
 compressor rotor spool.
----------------------------------------------------------------------------------------------------------------

    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 these replacements:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                   Action                                 Labor cost                Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace the stages 6-10 compressor rotor     64 work-hours x $85 per hour =           $1,018,600      $1,024,040
 spool.                                       $5,440.
----------------------------------------------------------------------------------------------------------------

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 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) Would not affect intrastate aviation in Alaska, and
    (3) Would 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-2020-0850; Project 
Identifier AD-2020-00288-E.

0
(a) Comments Due Date
    The FAA must receive comments by November 9, 2020.
0
(b) Affected ADs
    None.
0
(c) Applicability

    This AD applies to:
    (1) General Electric Company (GE) GEnx-1B64, GEnx-1B64/P1, GEnx-
1B64/P2, GEnx-1B67, GEnx-1B67/P1, GEnx-1B67/P2, GEnx-1B70, GEnx-
1B70/75/P1, GEnx-1B70/75/P2, GEnx-1B70/P1, GEnx-1B70/P2, GEnx-1B70C/
P1, GEnx-1B70C/P2, GEnx-1B74/75/P1, GEnx-1B74/75/P2, GEnx-1B76/P2, 
GEnx-1B76A/P2 model turbofan engines with stages 6-10 compressor 
rotor spools in the high-pressure compressor (HPC) assembly with the 
following part numbers (P/N) installed:
    (i) P/N 2357M30G01, P/N 2357M30G02, P/N 2439M35G01, P/N 
2439M35G02, or P/N 2445M40G02, all serial numbers (S/Ns);
    (ii) P/N 2610M90G01 with the S/Ns listed in paragraph 4., 
APPENDIX--A, Table 1 of the GE GEnx-1B Service Bulletin (SB) 72-0472 
R01, dated July 24, 2020 (``SB 72-0472''); and
    (iii) P/N 2628M56G01 with the S/Ns listed in paragraph 4., 
APPENDIX--A, Table 2 or Table 3 of SB 72-0472.
    (2) GEnx-2B67, GEnx-2B67/P, GEnx-2B67B model turbofan engines 
with the following stages 6-10 compressor rotor spools P/Ns 
installed:

[[Page 60106]]

    (i) P/N 2357M30G02, P/N 2439M35G02, or P/N 2445M40G02, all S/Ns;
    (ii) P/N 2340M36G01with S/Ns listed in paragraph 4., APPENDIX--
A, Table 1 of GE GEnx-2B SB 72-0415 R01, dated July 24, 2020 (``SB 
72-0415''); and
    (iii) P/N 2628M56G01 with S/Ns listed in paragraph 4., 
APPENDIX--A, Table 2 or Table 3 of SB 72-0415.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7230, Turbine Engine 
Compressor Section.

(e) Unsafe Condition

    This AD was prompted by a finding during an inspection that two 
stages 6-10 compressor rotor spools were damaged at similar 
locations. In addition, the manufacturer reported that certain 
stages 6-10 compressor rotor spool webs did not undergo a required 
fluorescent penetrant inspection (FPI) during production. The FAA is 
issuing this AD to prevent failure of the compressor rotor spool. 
The unsafe condition, if not addressed, could result in uncontained 
release of debris, 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 all affected GEnx-1B and GEnx-2B model turbofan engines, 
before exceeding the compliance time in Table 1 to paragraph (g)(1) 
of this AD, perform a borescope inspection (BSI) or eddy current 
inspection (ECI) of the stage 6, stage 7, and stage 8 webs, web 
transitions, and bore faces of the stages 6-10 compressor rotor 
spool in accordance with the Accomplishment Instructions, paragraph 
3, of SB 72-0472 (for GEnx-1B models) or the Accomplishment 
Instructions, paragraph 3, of SB 72-0415 (for GEnx-2B models). 
[GRAPHIC] [TIFF OMITTED] TP24SE20.000

    (i) For GEnx-1B model turbofan engines, except those identified 
in paragraph 4, APPENDIX--A, Table 3 of SB 72-0472, if the engines 
have previously undergone inspections of the aft web of stage 6, 
stage 7, and stage 8 of the stages 6-10 compressor rotor spool using 
both GE GEnx-1B SB 72-0448 R00, dated July 29, 2019, and GE GEnx-1B 
SB 72-0460 R00, dated October 30, 2019, regardless of the CSN 
accumulated on the stages 6-10 compressor rotor spool, perform the 
inspection required by paragraph (g)(1) of this AD no later than the 
next engine shop visit after the effective date of this AD.
    (ii) For GEnx-2B model turbofan engines, except those identified 
in paragraph 4., APPENDIX--A, Table 3 of SB 72-0415, if the engines 
have previously undergone inspections of the aft web of stage 6, 
stage 7, and stage 8 of the stages 6-10 compressor rotor spool using 
both GE GEnx-2B SB 72-385 R02, dated July 29, 2019, and GE GEnx-2B 
SB 72-0398 R00, dated October 30, 2019, regardless of the CSN 
accumulated on the stages 6-10 compressor rotor spool, perform the 
inspection required by paragraph (g)(1) of this AD no later than the 
next engine shop visit after the effective date of this AD.
    (2) For all affected GEnx-1B and GEnx-2B model turbofan engines, 
during the inspections required by paragraph (g)(1) of this AD, if a 
rejectable indication is found, before further flight, remove the 
stages 6-10 compressor rotor spool from service and replace it with 
a part eligible for installation.

(h) Definition

    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) Credit for Previous Action

    (1) For affected GEnx-1B model turbofan engines, you may take 
credit for the BSI or ECI required by paragraph (g)(1) of this AD, 
if the stages 6-10 compressor rotor spool webs, web transitions, and 
bore faces previously received an ECI using Subtask 72-31-45-160-002 
of TASK 72-31-45-200-807 in GE GEnx-1B Engine Manual 05-21-00, Life 
Limits 001 Mandatory Inspections, Rev. 31 dated, January 31, 2020, 
or earlier, and no rejectable indications were found.
    (2) For affected GEnx-2B model turbofan engines, you may take 
credit for the BSI or ECI required by paragraph (g)(1) of this AD, 
if the stages 6-10 compressor rotor spool webs, web transitions, and 
bore faces previously received an ECI using Subtask 72-31-45-160-002 
of TASK 72-31-45-200-801 in GE GEnx-2B Engine Manual 05-21-00, Life 
Limits 001 Mandatory Inspections, Rev. 24 dated, January 31, 2020, 
or earlier, and no rejectable indications were found.
    (3) For affected GEnx-1B and GEnx-2B model turbofan engines, you 
may take credit for the BSI or ECI required by paragraph (g)(1) of 
this AD, if you performed these inspections using GE GEnx-1B Service 
Bulletin (SB) 72-0472 R00, dated April 24, 2020, or GE GEnx-2B SB 
72-0415 R00, dated April 24, 2020, respectively, and no rejectable 
indications were found.

(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, 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.

[[Page 60107]]

    Issued on September 17, 2020.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2020-20947 Filed 9-23-20; 8:45 am]
BILLING CODE 4910-13-P