2021-21-05: Engine Controls

1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. 2. The FAA amends § 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. ER23NO21.189 (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. ER23NO21.190 (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 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