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.