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 Department of Transportation Federal Aviation Administration 14 CFR Part 39
[Docket No. FAA-2024-2417; Project Identifier AD-2024-00336-E]
RIN 2120-AA64
 AGENCY: Federal Aviation Administration (FAA), DOT.
 ACTION: Notice of proposed rulemaking (NPRM).
 SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 2020-20-17 and AD 2021-15-05, which apply to all General Electric Company (GE) Model GE90-110B1 and GE90-115B engines. AD 2020-20-17 prohibits dispatch of an airplane if certain status messages are displayed on the engine indicating and crew alerting system (EICAS) and if certain conditions are present; and as terminating action, requires revision of the existing FAA-approved minimum equipment list (MEL) by incorporating the dispatch restrictions into the MEL. AD 2021-15-05 requires initial and repetitive replacement of the full authority digital engine control (FADEC) integrated circuit (MN4) microprocessor. Since the FAA issued AD 2020-20-17 and AD 2021-15-05, the manufacturer has developed a software revision for the electronic engine control (EEC) FADEC that further mitigates the unsafe condition. This proposed AD would retain all the actions of AD 2020-20-17 and AD 2021-15-05, and it would also require upgrading the EEC FADEC software to an EEC FADEC software version eligible for installation as a terminating action. 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 December 16, 2024.
 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 
                        *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. *AD Docket:*
                         You may examine the AD docket at 
                        *regulations.gov*
                         under Docket No. FAA-2024-2417; 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. *Material Incorporated by Reference:* For GE material identified in this proposed AD, contact GE, 1 Neumann Way, Cincinnati, OH 45215; phone: (513) 552-3272; email:*aviation.fleetsupport@ge.com;*
                         website: 
                        *ge.com.*
                    You may view this material 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 (817) 222-5110.
 FOR FURTHER INFORMATION CONTACT: Alexander Thickstun, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (202) 267-8292; email: 
                        *alexander.m.thickstun@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-2024-2417; Project Identifier AD-2024-00336-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 revise 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 
                    *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 Alexander Thickstun, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198. 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 issued AD 2020-20-17, Amendment 39-21273 (85 FR 63443, October 8, 2020) (“AD 2020-20-17”) and AD 2021-15-05, Amendment 39-21652 (86 FR 43409, August 9, 2021) (“AD 2021-15-05”), for all GE Model GE90-110B1 and GE90-115B engines. AD 2020-20-17 was prompted by an in-service occurrence of loss of engine thrust control resulting in uncommanded high thrust. AD 2020-20-17 prohibits dispatch of an airplane if certain status messages are displayed on the EICAS and if certain conditions are present; and as terminating action, requires revision of the existing FAA-approved MEL by incorporating the dispatch restrictions listed in AD 2020-20-17 into the MEL. The agency issued AD 2020-20-17 to prevent dispatch of the airplane when certain faults caused by degradation of the MN4 integrated circuit in the FADEC are displayed and certain FADEC conditions are present which, if not addressed, could result in loss of engine thrust control and reduced control of the airplane. AD 2021-15-05 was also prompted by the in-service occurrence of loss of engine thrust control resulting in uncommanded high thrust. AD 2021-15-05 requires initial and repetitive replacement of the FADEC MN4 microprocessor. The agency issued AD 2021-15-05 to prevent failure of the FADEC MN4 microprocessor solder ball which, if not addressed, could result in 
                    ( print page 87318)
                    loss of engine thrust control and reduced control of the airplane. Actions Since AD 2020-20-17 and AD 2021-15-05 Were Issued Since the FAA issued AD 2020-20-17 and AD 2021-15-05, the manufacturer has developed a software revision for the FADEC. The FAA has determined that the software revision for the FADEC further mitigates the unsafe conditions specified AD 2020-20-17 and AD 2021-15-05, and therefore, must be required for the affected engines. 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. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed GE GE90-100 Service Bulletin 73-0117 R01, dated August 5, 2020, which the Director of the Federal Register approved for incorporation by reference as of October 23, 2020 (85 FR 63443, October 8, 2020). This material describes procedures for checking for an inbound FADEC EICAS “ENG EEC C1” status message and corresponding conditions. The FAA also reviewed GE GE90-100 Service Bulletin 73-0118, Revision 01, dated April 27, 2021, which the Director of the Federal Register approved for incorporation by reference as of September 13, 2021 (86 FR 43409, August 9, 2021). This material specifies procedures for replacing the FADEC MN4 microprocessor. This material 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. Proposed AD Requirements in This NPRM This proposed AD would retain all of the requirements of AD 2020-20-17 and AD 2021-15-05. Furthermore, this proposed AD would require upgrading the EEC FADEC software to an EEC FADEC software version that is eligible for installation as a terminating action for the retained requirements from AD 2020-20-17 and AD 2021-15-05. Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect 330 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
Parts cost
Cost per
                             product
Cost on U.S. operatorsRevise the existing MEL (Retained action from AD 2020-20-17)
1 work-hour × $85 per hour = $85
$0
$85
$28,050Remove and replace FADEC (Retained action from AD 2021-15-05)
1 work-hour × $85 per hour = $85
25,200
25,285
8,344,050Upgrade the EEC FADEC software (New Action)
1 work-hour × $85 per hour = $85
0
85
28,050
 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 that the 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
 1.The authority citation for part 39 continues to read as follows: Authority:
                    49 U.S.C. 106(g), 40113, 44701. § 39.13
 2.The FAA amends § 39.13 by: a.Removing Airworthiness Directives 2020-20-17, Amendment 39-21273 ( 85 FR 63443, October 8, 2020); and 2021-15-05, Amendment 39-21652 (86 FR 43409, August 9, 2021); and b.Adding the following new airworthiness directive: **General Electric Company:**
                         Docket No. FAA-2024-2417; Project Identifier AD-2024-00336-E. (a) Comments Due Date The FAA must receive comments on this airworthiness directive (AD) by December 16, 2024. (b) Affected ADs This AD replaces AD 2020-20-17, Amendment 39-21273 (85 FR 63443, October 8, 2020) (AD 2020-20-17); and AD 2021-15-05, Amendment 39-21652 (86 FR 43409, August 9, 2021) (AD 2021-15-05).
                        ( print page 87319) (c) Applicability This AD applies to General Electric Company (GE) Model GE90-110B1 and GE90-115B engines. (d) Subject Joint Aircraft System Component (JASC) Code 7320, Fuel Controlling System. (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 faults caused by degradation of the MN4 integrated circuit in the full authority digital engine control (FADEC) are displayed and certain FADEC conditions are present, and to prevent failure of the electronic engine control (EEC) FADEC integrated circuit (MN4) microprocessor solder ball. 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) Retained Actions From AD 2020-20-17 (1) After October 23, 2020 (the effective date of AD 2020-20-17), notwithstanding the provisions of the operator's minimum equipment list (MEL), dispatch of an airplane is prohibited if the engine indicating and crew alerting system (EICAS) displays the status message “ENG EEC C1 L” or “ENG EEC C1 R” and any condition is present that is listed in the Accomplishment Instructions, paragraphs 3.A.(2)(f), 3.A.3(a), or 3.A.(4) of GE GE90-100 Service Bulletin 73-0117 R01, dated August 5, 2020. (2) As terminating action for the requirements of paragraph (g)(1) of this AD, within 120 days of October 23, 2020 (the effective date of AD 2020-20-17), revise the existing FAA-approved MEL by incorporating into the MEL the dispatch restrictions listed in paragraph (g)(1) of this AD as a required operation or maintenance procedure. Specific alternative MEL wording to accomplish the actions specified in paragraph (g)(1) of this AD can be approved by the operator's principal operations or maintenance inspector. (h) Retained Actions From AD 2021-15-05 (1) Within the following compliance times after September 13, 2021 (the effective date of AD 2021-15-05), replace the FADEC MN4 microprocessor using an approved overhaul procedure: (i) For a FADEC MN4 microprocessor with 10,500 or more cycles since new (CSN), replace the FADEC MN4 microprocessor before accumulating 500 additional cycles on the FADEC MN4 microprocessor. (ii) For a FADEC MN4 microprocessor with 5,000 CSN or more, but fewer than 10,500 CSN, replace the FADEC MN4 microprocessor at the next FADEC component shop visit or before accumulating 11,000 CSN on the FADEC MN4 microprocessor, whichever occurs first. (2) Thereafter, repeat the replacement of the FADEC MN4 microprocessor at the first FADEC component shop visit after accumulating 5,000 cycles since the last replacement but before accumulating 11,000 cycles since the last replacement. (i) Retained Definitions From AD 2021-15-05 For the purpose of this AD: (1) An “approved overhaul procedure” is one of the following: (i) Replacement of the FADEC MN4 microprocessor using FADEC International-approved maintenance procedures; or (ii) Replacement of the FADEC MN4 microprocessor using the Accomplishment Instructions, paragraph 3.A., of GE GE90-100 Service Bulletin 73-0118, Revision 01, dated April 27, 2021. (2) A “FADEC component shop visit” is the induction of the FADEC into a repair facility to perform internal maintenance on the FADEC. (j) New Required Actions Within 180 days after the effective date of this AD, replace any EEC FADEC software version that is earlier than A.0.8.6 with an EEC FADEC software version that is eligible for installation. (k) Terminating Action The actions specified in paragraph (j) of this AD constitute terminating action for all the requirements of paragraphs (g) and (h) of this AD. (l) Installation Prohibition As of the effective date of this AD, no person may install on any engine, an EEC FADEC software version that is earlier than A.0.8.6. (m) Definition For the purpose of this AD, an “EEC FADEC software version that is eligible for installation” is any software version that is A.0.8.6 or later. (n) Alternative Methods of Compliance (AMOCs) (1) The Manager, AIR-520 Continued Operational Safety 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 AIR-520 Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (o) of this AD and email to: 
                        *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. (o) Additional Information For more information about this AD, contact Alexander Thickstun, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (202) 267-8292; email: 
                        *alexander.m.thickstun@faa.gov*. (p) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference (IBR) of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this material as applicable to do the actions required by this AD, unless the AD specifies otherwise. (3) The following material was approved for IBR on October 23, 2020 (85 FR 63443, October 8, 2020). (i) General Electric Company (GE) GE90-100 Service Bulletin 73-0117 R01, dated August 5, 2020. (ii) [Reserved] (4) The following material was approved for IBR on September 13, 2021 (86 FR 43409, August 9, 2021). (i) GE GE90-100 Service Bulletin 73-0118, Revision 01, dated April 27, 2021. (ii) [Reserved] (5) For GE material identified in this AD, contact GE, 1 Neumann Way, Cincinnati, OH 45215; phone: (513) 552-3272; email: 
                        *aviation.fleetsupport@ge.com;*
                         website: 
                        *ge.com.* (6) You may view this material 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 (817) 222-5110. (7) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit 
                        *www.archives.gov/​federal-register/​cfr/​ibr-locations*
                         or email 
                        *fr.inspection@nara.gov.* Issued on October 25, 2024. Suzanne Masterson, Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service.


[FR Doc. 2024-25377 Filed 10-31-24; 8:45 am] BILLING CODE 4910-13-P