Airworthiness Directive · Amendment 39-23012 · Fuel controlling system
General Electric Company Engines
This AD applies to General Electric Company (GE) Model GE90-110B1 and GE90-115B engines.
The FAA is superseding Airworthiness Directive (AD) 2020-20-17 and AD 2021-15-05 for 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 AD retains all the actions of AD 2020-20-17 and AD 2021-15-05, and also requires upgrading the EEC FADEC software to an EEC FADEC software version eligible for installation as a terminating action. The FAA is issuing this AD to address the unsafe condition on these products.
(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.
(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.
This paragraph restates the definitions of paragraph (h) of AD 2021-15-05, with new service information included for the definition of paragraph (h)(1)(ii). 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, or of GE GE90-100 Service Bulletin 73-0118, Revision 02, dated November 15, 2024.
(2) A “FADEC component shop visit” is the induction of the FADEC into a repair facility to perform internal maintenance on the FADEC.
Within 180 days after the effective date of this AD, replace any EEC FADEC software version that is earlier than A.0.8.6 (prior to GE GE90-100 Service Bulletin 73-0122) with an EEC FADEC software version that is eligible for installation.
The actions specified in paragraph (j) of this AD constitute terminating action for all the requirements of paragraphs (g) and (h) of this AD.
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 (prior to GE GE90-100 Service Bulletin 73-0122).
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.
