Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede Airworthiness Directive (AD) 2017-07- 04, which applies to General Electric Company (GE) GE90-110B1 and GE90- 115B turbofan engines with certain high-pressure compressor (HPC) rotor stage 2-5 spools installed. AD 2017-07-04 resulted from reports of cracks in HPC rotor stage 2-5 spool aft spacer arms. Since we issued AD 2017-07-04, GE released a new service bulletin (SB) that increases the number of affected HPC rotor stage 2-5 spools. Additionally, we learned that we inadvertently omitted certain HPC rotor stage 2-5 spools from the applicability of AD 2017-07-04. This proposed AD would require removing certain HPC rotor stage 2-5 spools from service before reaching the new reduced life limit and replacing them with parts eligible for installation. We are proposing this AD to correct the unsafe condition on these products.