Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for certain Engine Alliance GP7270 and GP7277 turbofan engines. This proposed AD was prompted by damage to the high-pressure compressor (HPC) stage 7-9 spool caused by failure of the baffle plate feature on affected HPC stage 6 disks. This proposed AD would require initial and repetitive borescope inspections of the baffle plate feature and removal from service of the HPC stage 6 disk before further flight, if the plate is missing material. This proposed AD would also require mandatory removal from service of these HPC stage 6 disks at the next HPC module exposure. We are proposing this AD to prevent uncontained failure of the HPC stage 7-9 spool, uncontained engine failure, and damage to the airplane.