Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to CFM International (CFMI) CFM56-5/- 5B/-5C series turbofan engines. This proposal would require initial and repetitive borescope inspections of the stage 1 disk bore of certain high pressure compressor rotor (HPCR) stage 1-2 spools for rubs and scratches, and replacement, if found rubbed or scratched, with a serviceable part. This proposal would also require removal and replacement of certain stationary number 3 bearing aft air/oil seals as terminating action to the inspection program. This proposal is prompted by a report of an engine found with a rub on the forward corner of the HPCR stage 1 disk bore due to contact with the stationary number 3 bearing aft air/oil seal. The actions specified by the proposed AD are intended to prevent a failure of the stage 1 disk of the HPCR stage 1-2 spool, which could result in an uncontained engine failure and damage to the aircraft.