Airworthiness Directives; General Electric Company Turbofan Engines, 20094-20097 [2021-07550]

Download as PDF 20094 Federal Register / Vol. 86, No. 72 / Friday, April 16, 2021 / Proposed Rules DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2021–0273; Project Identifier AD–2021–00050–E] RIN 2120–AA64 Airworthiness Directives; General Electric Company Turbofan Engines Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM). AGENCY: The FAA proposes to adopt 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 proposed AD was prompted by an in-service occurrence of loss of engine thrust control resulting in uncommanded high thrust. This proposed AD would require revising the operator’s existing FAA-approved minimum equipment list (MEL) by incorporating into the MEL the dispatch restrictions listed in this AD. This proposed AD would also require initial and repetitive replacement of the electronic engine control (EEC) MN4 microprocessor. 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 June 1, 2021. 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; jbell on DSKJLSW7X2PROD with PROPOSALS SUMMARY: VerDate Sep<11>2014 16:09 Apr 15, 2021 Jkt 253001 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 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 NPRM, any comments received, and other information. The street address for Docket Operations is listed above. 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: 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 ADDRESSES. Include ‘‘Docket No. FAA–2021–0273; Project Identifier AD– 2021–00050–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 proposal 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 agency will also post a report summarizing each substantive verbal contact received about this NPRM. 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 PO 00000 Frm 00058 Fmt 4702 Sfmt 4702 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, Aviation Safety 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 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. This condition, if not addressed, could result in loss of engine thrust control and reduced control of the airplane. FAA’s Determination The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design. Related Service Information Under 1 CFR Part 51 The FAA reviewed GE GEnx–1B Service Bulletin (SB) 73–0097 R01, dated January 29, 2021, and R00, dated December 17, 2020; and GE GEnx–2B SB 73–0090 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 reasonably available because the interested parties have access to it through their normal course of business or by the means identified in ADDRESSES. Proposed AD Requirements in This NPRM This proposed AD would require revising the existing operator’s FAA- E:\FR\FM\16APP1.SGM 16APP1 Federal Register / Vol. 86, No. 72 / Friday, April 16, 2021 / Proposed Rules approved MEL by incorporating into the MEL the dispatch restrictions listed in paragraph (g) of this AD. This proposed AD would also require initial and repetitive replacement of the EEC MN4 microprocessor using an approved overhaul procedure. 20095 Interim Action Costs of Compliance The FAA considers that this proposed AD would be an interim action. If final action is later identified, the FAA might consider additional rulemaking. The FAA estimates that this AD, if adopted as proposed, would affect 308 engines installed on airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD: ESTIMATED COSTS Action Labor cost Revise operator’s FAA-approved MEL ........... Replace EEC MN4 microprocessor ................ 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. jbell on DSKJLSW7X2PROD with PROPOSALS 16:09 Apr 15, 2021 Jkt 253001 (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 1. The authority citation for part 39 continues to read as follows: ■ Authority: 49 U.S.C. 106(g), 40113, 44701. [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive: General Electric Company: Docket No. FAA– 2021–0273; Project Identifier AD–2021– 00050–E. (a) Comments Due Date The FAA must receive comments on this airworthiness directive (AD) by June 1, 2021. (b) Affected ADs None. (c) Applicability This AD applies to General Electric Company (GE) GEnx–1B64, GEnx–1B64/P1, PO 00000 Frm 00059 Fmt 4702 Sfmt 4702 Cost per product $0 25,200 ■ 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. VerDate Sep<11>2014 1 work-hour × $85 per hour = $85 1 work-hour × $85 per hour = $85 § 39.13 Regulatory Findings Parts cost $85 25,285 Cost on U.S. operators $26,180 7,787,780 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. E:\FR\FM\16APP1.SGM 16APP1 20096 Federal Register / Vol. 86, No. 72 / Friday, April 16, 2021 / Proposed Rules Figure 1 to Paragraph (g)(l)- Dispatch Restriction for Engine Indicating and Crew Alerting System (EICAS) MESSAGE ENG EEC Cl for GEnx-lB Dispatch of an airplane is prohibited if the engine indicating and crew alerting system (EICAS) displays the status message "ENG EEC C 1 X'' (where "X'' is engine position: "L" or "R") and any of the following conditions exist: i. None of the maintenance messages in the Central Maintenance Computing Function (CMCF) correlate with "ENG EEC C 1 X'' status message; or ii. The following maintenance message fault codes combination exists in the CMCF for either channel A or B (where "X" is engine position: "1" or "2"). Fault Combination Description {76-1953X (CH-A)} {TLA out of range fault} AND {FMV/FSV disagree fault OR FMV/FSV out of range fault (on the same channel as TLA out of range fault)} jbell on DSKJLSW7X2PROD with PROPOSALS VerDate Sep<11>2014 16:09 Apr 15, 2021 Jkt 253001 {73-3204X OR 73-3121X OR 73-1205X OR 73-1122X} {76-2953X (CH-B)} AND {73-3204X OR 73-3121X OR 73-2205X OR 73-2122X} 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 PO 00000 Frm 00060 Fmt 4702 Sfmt 4702 actions specified in Figure 2 can be approved by the operator’s principal operations or maintenance inspector. E:\FR\FM\16APP1.SGM 16APP1 EP16AP21.000</GPH> AND (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 Corresponding Fault Codes Combination Federal Register / Vol. 86, No. 72 / Friday, April 16, 2021 / Proposed Rules 20097 Figure 2 to Paragraph (g)(2) - Dispatch Restriction for EICAS MESSAGE ENG EEC Cl for GEnx-2B Dispatch of an airplane is prohibited if the engine indicating and crew alerting system (EICAS) displays the status message "ENG X EEC Cl" (where "X'' is engine position: "1," "2," "3," or "4") and any of the following conditions exist: i. None of the maintenance messages in the Central Maintenance Computer (CMC) correlate with "ENG X EEC Cl" status message; or ii. The following maintenance message fault codes combination exists in the CMC for either channel A or B (where "X'' is engine position: "1," "2," "3," or "4"). Fault Combination Description Corresponding Fault Codes Combination {TLA out of range fault} {78X13 (CH-A)} AND AND {7X132 OR 7X144 OR 7X130 OR 7X145} {FMV/FSV disagree fault OR FMV/FSV out of range fault (on the same channel as TLA out of range fault)} AND jbell on DSKJLSW7X2PROD with PROPOSALS (h) Definition For the purposes of this AD, an approved overhaul procedure is one of the following: (i) Replacement of the EEC MN4 microprocessor using FADEC Internationalapproved maintenance procedures; or (ii) Replacement of the EEC MN4 microprocessor using the Accomplishment Instructions, paragraph 3., as applicable, of GEnx–1B Service Bulletin (SB) 73–0097 R00, dated December 17, 2020, or R01, dated January 29, 2021; or GEnx–2B SB 73–0090 R00, dated December 17, 2020, or R01, dated January 28, 2021. (i) Installation Prohibition After the effective date of this AD, do not install onto any engine an EEC with a main channel board that was subject to more than three replacements of the EEC MN4 microprocessor. (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 VerDate Sep<11>2014 16:09 Apr 15, 2021 Jkt 253001 {7X132 OR 7X144 OR 7X133 OR 7X146} 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 Related Information. Information may be emailed to: ANE-ADAMOC@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. Issued on April 7, 2021. Lance T. Gant, Director, Compliance & Airworthiness Division, Aircraft Certification Service. (k) Related Information [Docket No. FAA–2021–0269; Project Identifier MCAI–2020–01417–T] (1) 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: 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. PO 00000 Frm 00061 Fmt 4702 Sfmt 4702 [FR Doc. 2021–07550 Filed 4–15–21; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 RIN 2120–AA64 Airworthiness Directives; Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Airplanes Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM). AGENCY: The FAA proposes to adopt a new airworthiness directive (AD) for certain Airbus Canada Limited Partnership Model BD–500–1A10 and SUMMARY: E:\FR\FM\16APP1.SGM 16APP1 EP16AP21.001</GPH> (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) Thereafter, replace the EEC MN4 microprocessor before accumulating 11,000 cycles since the last replacement. (ii) [Reserved] {78X14 (CH-B)}

Agencies

[Federal Register Volume 86, Number 72 (Friday, April 16, 2021)]
[Proposed Rules]
[Pages 20094-20097]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-07550]



[[Page 20094]]

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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]
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 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 proposed AD was prompted by an in-service occurrence of 
loss of engine thrust control resulting in uncommanded high thrust. 
This proposed AD would require revising the operator's existing FAA-
approved minimum equipment list (MEL) by incorporating into the MEL the 
dispatch restrictions listed in this AD. This proposed AD would also 
require initial and repetitive replacement of the electronic engine 
control (EEC) MN4 microprocessor. 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 June 1, 
2021.

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: [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.

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

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:

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 ADDRESSES. Include ``Docket No. FAA-2021-0273; Project Identifier 
AD-2021-00050-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 proposal 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 agency will also post a report summarizing each 
substantive verbal contact received about this NPRM.

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, Aviation Safety 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 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. This condition, if not addressed, could result in loss 
of engine thrust control and reduced control of the airplane.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed GE GEnx-1B Service Bulletin (SB) 73-0097 R01, 
dated January 29, 2021, and R00, dated December 17, 2020; and GE GEnx-
2B SB 73-0090 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 reasonably available because 
the interested parties have access to it through their normal course of 
business or by the means identified in ADDRESSES.

Proposed AD Requirements in This NPRM

    This proposed AD would require revising the existing operator's 
FAA-

[[Page 20095]]

approved MEL by incorporating into the MEL the dispatch restrictions 
listed in paragraph (g) of this AD. This proposed AD would also require 
initial and repetitive replacement of the EEC MN4 microprocessor using 
an approved overhaul procedure.

Interim Action

    The FAA considers that this proposed AD would 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, if adopted as proposed, would 
affect 308 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
----------------------------------------------------------------------------------------------------------------
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

    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:

General Electric Company: Docket No. FAA-2021-0273; Project 
Identifier AD-2021-00050-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by June 1, 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 20096]]

[GRAPHIC] [TIFF OMITTED] TP16AP21.000

    (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 20097]]

[GRAPHIC] [TIFF OMITTED] TP16AP21.001

    (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) Thereafter, replace the EEC MN4 microprocessor before 
accumulating 11,000 cycles since the last replacement.
    (ii) [Reserved]

(h) Definition

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

(i) Installation Prohibition

    After the effective date of this AD, do not install onto any 
engine an EEC with a main channel board that was subject to more 
than three replacements of the EEC MN4 microprocessor.

(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 Related Information. 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.

(k) Related Information

    (1) 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].
    (2) For 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. 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 April 7, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-07550 Filed 4-15-21; 8:45 am]
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