Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires performing a fluorescent penetrant inspection (FPI) of the low-pressure turbine (LPT) rotor stage 3 disk at every shop visit at which the LPT module is separated from the engine. This AD was prompted by seven reports of uncontained failures of LPT rotor stage 3 disks and eight reports of cracked LPT rotor stage 3 disks found during shop visit inspections. We are issuing this AD to prevent LPT rotor separation, which could result in an uncontained engine failure and damage to the airplane.