Airworthiness Directives; General Electric Company GE90 Series Turbofan Engines

This amendment adopts a new airworthiness directive (AD) that is applicable to General Electric Company (GE) GE90 series turbofan engines. This action supersedes Telegraphic AD T97-09-51 that currently requires visual checks of the engine Debris Monitoring System (DMS) sensor for bearing debris, and, if necessary, performing procedures for additional maintenance actions. In addition, that AD requires replacing Variable Speed Constant Frequency (VSCF) gearshaft flange ball bearings that may incorporate rivets that are manufactured of improper material with serviceable bearings. This action references a later revision of the applicable Service Bulletin (SB) that includes additional engine serial numbers; however, these changes do not affect the Applicability or compliance requirements of this AD. This amendment is prompted by the issuance of the new revision to the SB. The actions specified by this AD are intended to prevent a VSCF gearshaft flange ball bearing failure, which could result in an inflight engine shutdown.