Airworthiness Directives; CFM International, S.A. Turbofan Engines

The FAA is adopting a new airworthiness directive (AD) for certain CFM International, S.A. (CFM) LEAP-1B model turbofan engines. This AD was prompted by multiple commanded in-flight shutdowns (IFSDs) due to inner radial drive shaft (RDS) failure. This AD requires initial and repetitive inspections of the transfer gearbox (TGB) scavenge screens and, depending on the results of the inspections, replacement or rework of the affected inner RDS. As a mandatory terminating action to the initial and repetitive inspections of the TGB scavenge screens, this AD requires replacement or rework of the affected inner RDS. This AD also prohibits the installation of an engine with an affected inner RDS onto an airplane that already has one engine with an affected inner RDS installed. The FAA is issuing this AD to address the unsafe condition on these products.