[Federal Register Volume 86, Number 223 (Tuesday, November 23, 2021)]
[Rules and Regulations]
[Pages 66447-66453]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-25491]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0273; Project Identifier AD-2021-00050-E; 
Amendment 39-21765; AD 2021-21-05]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
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, 
GEnx-2B67, GEnx-2B67/P, and GEnx-2B67B model turbofan engines. This AD 
was prompted by an in-service occurrence of loss of engine thrust 
control resulting in uncommanded high thrust. This AD requires revising 
the operator's existing FAA-approved minimum equipment list (MEL) by 
incorporating into the MEL the dispatch restrictions listed in this AD. 
This AD also requires initial and repetitive replacement of the 
electronic engine control (EEC) MN4 microprocessor. The FAA is issuing 
this AD to address the unsafe condition on these products.

DATES: This AD is effective December 28, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of December 28, 
2021.

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 at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2021-0273.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0273; 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, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7743; fax: (781) 238-7199; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to all 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, GEnx-2B67, GEnx-2B67/P, and GEnx-2B67B model 
turbofan engines. The NPRM published in the Federal

[[Page 66448]]

Register on April 16, 2021 (86 FR 20094). The NPRM was prompted by a 
report from the manufacturer of an in-service loss of engine thrust 
control on a GE90-115B model turbofan engine on October 27, 2019, that 
resulted in uncommanded high thrust. Analysis by the manufacturer found 
accumulated thermal cycles of the MN4 integrated circuit in the EEC, 
through normal operation, causes the solder ball joints to wear out and 
eventually fail over time. Since the GE90 and the GEnx model turbofan 
engines share the same EEC hardware and experience similar thermal and 
vibratory environments, the manufacturer determined that GEnx model 
turbofan engines are susceptible to the same type of failure. In the 
NPRM, the FAA proposed to require revising the existing operator's FAA-
approved MEL by incorporating into the MEL the dispatch restrictions 
listed in paragraph (g) of this AD. In the NPRM, the FAA also proposed 
to require initial and repetitive replacement of the EEC MN4 
microprocessor using an approved overhaul procedure. The FAA is issuing 
this AD to address the unsafe condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from nine commenters. The commenters were 
Air Line Pilots Association, International (ALPA), Japan Airlines, 
American Airlines (American), Cathay Pacific Airways (Cathay Pacific), 
Jetstar Airways (Jetstar), GE, The Boeing Company (Boeing), United 
Airlines Engineering (UAL Engineering), and United Parcel Service 
(UPS). The following presents the comments received on the NPRM and the 
FAA's response to each comment.

Request To Require a Revision to the Master Minimum Equipment List

    ALPA and Japan Airlines suggested that the FAA modify paragraph (g) 
of the NPRM to require a revision to the master minimum equipment list 
(MMEL), similar to that required for the operator's FAA-approved MEL. 
ALPA stated that while revising each operator's FAA-approved MEL would 
be required, the NPRM does not mention revision of the MMEL through 
either the Flight Operations Evaluation Board or the Aircraft 
Evaluation Group process. Japan Airlines reasoned that when the 
dispatch restriction is necessary, it should be specified in the MMEL, 
not only in the operator's FAA-approved MEL.
    The FAA disagrees. The FAA does not plan to require the requested 
change to the MMEL because the required change to the MEL is an interim 
action. The design approval holder is working on a terminating action 
to correct the unsafe condition. The FAA did not change this AD as a 
result of this comment.

Request To Clarify the Compliance for Central Maintenance Computing 
Function

    Japan Airlines requested that the FAA clarify which function within 
the Central Maintenance Computing Function (CMCF) operators should use 
to check for the engine indicating and crew alerting system (EICAS) and 
maintenance message. Japan Airlines stated that Figure 1 to paragraph 
(g)(1) of the NPRM does not clearly specify whether the CMCF Existing 
Fault function is the only function that needs to be checked or if 
other CMCF functions also need to be checked.
    The FAA disagrees with the need to clarify Figure 1 to paragraph 
(g)(1) of this AD to indicate which function within the CMCF operators 
should use to check for EICAS and maintenance messages. The FAA notes 
that operators should follow the procedures in their approved fault 
isolation manuals when checking for faults. The FAA did not change this 
AD as a result of this comment.

Request To Change Compliance To Include Main Channel Board

    American suggested that the FAA change paragraph (g)(3) of the NPRM 
from ``replace the EEC MN4 microprocessor'' to ``replace the EEC MN4 
microprocessor or main channel board (MCB).'' American reasoned that 
they have had to replace the MCB during EEC MN4 microprocessor repairs 
due to unrelated findings. American also stated that this change would 
allow such instances to take credit for satisfying the AD, which seems 
to align with the intention of the NPRM based on the proposed 
requirements specified in paragraph (i) of the NPRM.
    The FAA acknowledges that the EEC MN4 microprocessor can be 
replaced with a new one as a piece part, part of the MCB, or part of 
the EEC for compliance with paragraph (g)(3) of this AD. The FAA does 
not find it necessary to change this AD to reference replacement of the 
MCB.

Request To Clarify Soft Time Cycles of Revised Service Information

    American commented that R02 of GE GEnx-1B Service Bulletin (SB) 73-
0097, dated May 17, 2021 (GEnx-1B SB 73-0097), and GE GEnx-2B SB 73-
0090, dated May 20, 2021 (GEnx-2B SB 73-0090) include a new ``soft 
time'' requirement of 9,500 cycles that should be attained before the 
EEC MN4 microprocessor be replaced. American requested that if the FAA 
incorporated R02 of these SBs in its AD, the FAA should explicitly 
state that replacement of EEC MN4 microprocessor after the soft time of 
9,500 cycles is not part of the AD requirements. American commented 
that this would allow for instances where the EEC MN4 microprocessor or 
MCB was replaced prior to the soft time.
    This AD requires replacing the EEC MN4 microprocessor at intervals 
not to exceed 11,000 cycles since new (CSN) or cycles since last 
replacement. The recommended soft time of 9,500 CSN prior to replacing 
the EEC MN4 microprocessor specified in R02 of GE GEnx-1B SB 73-0097 
and GEnx-2B SB 73-0090, is not mandated by this AD. The FAA did not 
change this AD as a result of this comment.

Request To Change Compliance To Allow Dispatch per MMEL

    Cathay Pacific commented that Figure 2 to paragraph (g)(2) of the 
NPRM should specify that dispatch is allowed per the MMEL or dispatch 
deviation guide (DDG).
    The FAA disagrees. After this AD is effective, if any of the fault 
combinations defined in Figure 2 to paragraph (g)(2) of this AD are 
present, then dispatch is prohibited, notwithstanding the provisions of 
the MEL and the DDG. The FAA did not change this AD as a result of this 
comment.

Request To Revise or Remove Installation Prohibition

    Cathay Pacific, GE, and Jetstar suggested revision or removal of 
paragraph (i), Installation Prohibition, of the NPRM that prohibits 
installation onto any engine an EEC with an MCB that was subject to 
more than three replacements of the EEC MN4 microprocessor. GE 
suggested removing the Installation Prohibition altogether. Jetstar 
questioned the need to include the Installation Prohibition in 
paragraph (h), Definition, which defines an approved overhaul 
procedure. Cathay Pacific suggested revising this paragraph to ``do not 
install an EEC without compliance of the GE SB 73-0097/SB 73-0090.'' 
Jetstar stated that the EEC MN4 microprocessor replacement is managed 
by the original equipment manufacturer's (OEM) internal maintenance 
procedures, and operators do not have visibility into the number

[[Page 66449]]

of replacements that have been performed.
    As stated by the commenters, the EEC MN4 microprocessor replacement 
is managed by the OEM's internal maintenance procedures and, therefore, 
not necessary in this AD. The FAA has removed the Installation 
Prohibition from this AD.

Request To Revise Compliance Time

    GE recommended that the FAA revise the compliance time in paragraph 
(g) of the NPRM to account for situations in which cycles accumulated 
on the EEC MN4 microprocessor cannot be determined through operator 
maintenance logs or FADEC International shop visit reports. GE proposed 
that, for these situations, the compliance time allow for replacing the 
EEC MN4 microprocessor after 12 years since EEC entry into service 
(EIS) for GEnx-1B model turbofan engines and 14 years since EEC EIS for 
GEnx-2B model turbofan engines.
    The FAA agrees. The commenter's recommended replacement time of 12 
years and 14 years since EEC EIS for GEnx-1B and GEnx-2B model turbofan 
engines, respectively, is based on the average yearly utilization of 
those engines with an added margin to account for higher utilization 
engines. The FAA revised paragraph (g)(3) of this AD to require 
replacement of the EEC MN4 microprocessor at the compliance times noted 
by GE when cycles accumulated on the EEC MN4 microprocessor cannot be 
determined. This change to this AD imposes no additional burden on 
operators.

Request To Update Service Information Revision

    GE recommended that the FAA contact GE before publication of this 
final rule to update the service bulletin references. GE commented 
that, at the time of its comment, the latest issued service bulletins 
are GEnx-1B SB 73-0097 R02, dated May 17, 2021, and GEnx-2B SB 73-0090 
R02, dated May 20, 2021.
    The FAA has updated this AD to reference GEnx-1B SB 73-0097 R02, 
dated May 17, 2021, and GEnx-2B SB 73-0090 R03, dated August 18, 2021. 
This change does not affect the instructions for replacing the EEC MN4 
microprocessor and places no additional burden on operators.

Request To Clarify Dispatch Restrictions

    Boeing requested that the FAA update Figure 1 to paragraph (g)(1) 
of the NPRM to indicate ``Prior to each flight with EICAS Message ENG 
EEC C1 X, check for the fault combinations in the table.'' Boeing also 
requested that the FAA update Figure 2 to paragraph (g)(2) of the NPRM 
to indicate ``Prior to each flight with EICAS Message ENG X EEC C1, 
check for the fault combinations in the table.'' Boeing noted that 
dispatch is allowed with the ENG EEC C1 L(R) status message for the 
time specified in the MMEL, which may encompass several flights. Boeing 
noted that new faults could arise during MMEL dispatch. Boeing 
concluded that the NPRM should clarify that the inspection for the 
underlying fault messages should be accomplished prior to each flight.
    The FAA agrees to clarify the AD requirement for operators to check 
for fault combinations prior to each flight. The FAA updated Figure 1 
to paragraph (g)(1) of this AD by adding ``Prior to each flight with 
engine indicating and crew alerting system (EICAS) Message ``ENG EEC C1 
X'' (where ``X'' is engine position: ``L'' or ``R''), check for 
faults.'' The FAA updated Figure 2 to paragraph (g)(2) of this AD by 
adding ``Prior to each flight with engine indicating and crew alerting 
system (EICAS) Message ``ENG X EEC C1'' (where ``X'' is engine 
position: ``1,'' ``2,'' ``3,'' or ``4''), check for faults.''

Request To Add Additional Fault Codes

    Boeing requested that the FAA revise Figure 2 to paragraph (g)(2) 
of the NPRM to add maintenance messages 7X963 (CH A) and 7X964 (CH B). 
Boeing reasoned that the TLA out of range fault is identified by 
different fault codes in a new version of the maintenance computer 
software. Boeing noted that adding the new fault codes would cover the 
eventual release of the new fault codes.
    The FAA agrees. The FAA revised Figure 2 to paragraph (g)(2) of 
this AD by adding ``OR 7X963 (CH[hyphen]A)'' and ``OR 7X964 
(CH[hyphen]B).''

Request To Revise Effectivity of EEC Replacement

    UAL Engineering requested that the FAA update paragraph (c), 
Applicability, of the NPRM to reference GE GEnx-1B SB 73-0097 for EEC 
part number (P/N) applicability.
    The FAA disagrees. All EEC P/Ns currently installed on affected 
GEnx-1B and GEnx-2B model turbofan engines are susceptible to the 
unsafe condition addressed by this AD. The FAA did not change this AD 
as a result of this comment.

Request Allowance To Accomplish a Manual Review for Maintenance 
Messages

    UPS requested the FAA revise the NPRM to allow for the 
accomplishment of a manual review to inspect for any correlated 
maintenance messages on the flight leg in which the C1 fault was 
present in the event that an EEC C1 EICAS message is displayed without 
a correlated fault in the central maintenance computer (CMC). UPS 
reasoned that both Boeing and GE have confirmed that six maintenance 
messages (7x310, 7x311, 7x312, 7x069, 7x071, and 7x073) correlate to C1 
faults for which the cockpit CMC screen will not show a correlation.
    The FAA agrees that six maintenance messages correlate to EICAS 
Message ``ENG EEC C1,'' but do not show a correlation to ``ENG EEC C1'' 
in the cockpit CMC screen. The CMC maintenance software lacks the 
capability to correlate those six maintenance messages, and currently 
the only available method for correlating those six maintenance 
messages is by performing a manual review. The FAA disagrees, however, 
with changing this AD, as the method for establishing correlation is 
not prescribed in this AD.

Support for the AD

    ALPA, Jetstar, UAL Engineering, and American expressed support for 
the proposed rule with the comments previously discussed.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes, and 
any other changes described previously, this AD is adopted as proposed 
in the NPRM. None of the changes will increase the economic burden on 
any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed GE GEnx-1B Service Bulletin (SB) 73-0097 R02, 
dated May 17, 2021, R01, dated January 29, 2021, and R00, dated 
December 17, 2020; and GE GEnx-2B SB 73-0090 R03, dated August 18, 
2021, R02, dated May 20, 2021, R01, dated January 28, 2021, and R00, 
dated December 17, 2020. This service information specifies procedures 
for replacing the EEC MN4 microprocessor on GEnx-1B and GEnx-2B model 
turbofan engines, as applicable. This service information is

[[Page 66450]]

reasonably available because the interested parties have access to it 
through their normal course of business or by the means identified in 
ADDRESSES.

Interim Action

    The FAA considers this AD to be an interim action. If final action 
is later identified, the FAA might consider additional rulemaking.

Costs of Compliance

    The FAA estimates that this AD affects 308 engines installed on 
airplanes 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
----------------------------------------------------------------------------------------------------------------
Revise operator's FAA-approved MEL....  1 work-hour x $85 per                 $0             $85         $26,180
                                         hour = $85.
Replace EEC MN4 microprocessor........  1 work-hour x $85 per             25,200          25,285       7,787,780
                                         hour = $85.
----------------------------------------------------------------------------------------------------------------

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:

2021-21-05 General Electric Company: Amendment 39-21765; Docket No. 
FAA-2021-0273; Project Identifier AD-2021-00050-E.

(a) Effective Date

    This airworthiness directive (AD) is effective December 28, 
2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to 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, GEnx-2B67, GEnx-2B67/P, and 
GEnx-2B67B model turbofan engines.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7600, Engine 
Controls.

(e) Unsafe Condition

    This AD was prompted by an in-service occurrence of loss of 
engine thrust control resulting in uncommanded high thrust. The FAA 
is issuing this AD to prevent dispatch of the airplane when certain 
conditions caused by degradation of the MN4 microprocessor in the 
electronic engine control (EEC) are present. The unsafe condition, 
if not addressed, could result in loss of engine thrust control and 
reduced control of 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 model turbofan engines, within 120 
days of the effective date of this AD, revise the operator's 
existing FAA-approved minimum equipment list (MEL) by incorporating 
into the MEL the dispatch restriction specified in Figure 1 to 
paragraph (g)(1) of this AD, as a required operation or maintenance 
procedure.
    Note 1 to paragraph (g)(1): Specific alternative MEL wording to 
accomplish the actions specified in Figure 1 can be approved by the 
operator's principal operations or maintenance inspector.

[[Page 66451]]

[GRAPHIC] [TIFF OMITTED] TR23NO21.189

    (2) For all affected GEnx-2B model turbofan engines, within 120 
days of the effective date of this AD, revise the operator's 
existing FAA-approved MEL by incorporating into the MEL the dispatch 
restriction specified in Figure 2 to paragraph (g)(2) of this AD, as 
a required operation or maintenance procedure.
    Note 2 to paragraph (g)(2): Specific alternative MEL wording to 
accomplish the actions specified in Figure 2 can be approved by the 
operator's principal operations or maintenance inspector.

[[Page 66452]]

[GRAPHIC] [TIFF OMITTED] TR23NO21.190

    (3) For all affected engines, before the EEC reaches 11,000 
cycles since new, replace the EEC MN4 microprocessor using an 
approved overhaul procedure.
    (i) If the number of accumulated cycles on the EEC MN4 
microprocessor cannot be determined through operator maintenance 
logs or FADEC International shop visit reports, before the EEC 
exceeds 12 years since entry into service (EIS) for affected GEnx-1B 
model turbofan engines or 14 years since EIS for affected GEnx-2B 
model turbofan engines, replace the EEC MN4 microprocessor using an 
approved overhaul procedure.
    (ii) [Reserved]
    (4) Thereafter, replace the EEC MN4 microprocessor before 
accumulating 11,000 cycles since the last replacement.

(h) Definition

    For the purposes of this AD, an ``approved overhaul procedure'' 
is one of the following:
    (1) Replacement of the EEC MN4 microprocessor using FADEC 
International-approved maintenance procedures; or
    (2) Replacement of the EEC MN4 microprocessor using the 
Accomplishment Instructions, paragraph 3., as applicable, of:
    (i) GE GEnx-1B Service Bulletin (SB) 73-0097 R00, dated December 
17, 2020; R01, dated January 29, 2021; or R02, dated May 17, 2021; 
or
    (ii) GE GEnx-2B SB 73-0090 R00, dated December 17, 2020; R01, 
dated January 28, 2021; R02, dated May 20, 2021; or R03, dated 
August 18, 2021.

(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. Information may be emailed 
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

    For more information about this AD, contact Mehdi Lamnyi, 
Aviation Safety 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

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) GE GEnx-1B Service Bulletin (SB) 73-0097 R02, dated May 17, 
2021.
    (ii) GE GEnx-1B SB 73-0097 R01, dated January 29, 2021.
    (iii) GE GEnx-1B SB 73-0097 R00, dated December 17, 2020.
    (iv) GE GEnx-2B SB 73-0090 R03, dated August 18, 2021.
    (v) GE GEnx-2B SB 73-0090 R02, dated May 20, 2021.
    (vi) GE GEnx-2B SB 73-0090 R01, dated January 28, 2021.
    (vii) GE GEnx-2B SB 73-0090 R00, dated December 17, 2020.
    (3) For GE service information identified in this AD, contact 
General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: [email protected]; 
website: www.ge.com.
    (4) You may view this service information at FAA, Airworthiness 
Products Section, Operational Safety Branch, 1200 District Avenue, 
Burlington, MA 01803. For

[[Page 66453]]

information on the availability of this material at the FAA, call 
(781) 238-7759.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on October 5, 2021.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2021-25491 Filed 11-22-21; 8:45 am]
BILLING CODE 4910-13-P