Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain CFM International, S.A. (CFM) LEAP-1B model turbofan engines. This proposed AD was prompted by multiple commanded in-flight shutdowns (IFSDs) due to inner radial drive shaft (RDS) failure. This proposed AD would require 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 proposed AD would require replacement or rework of the affected inner RDS. This proposed AD would also prohibit 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 proposing this AD to address the unsafe condition on these products.