Airworthiness Directives; CFM International CFM56-3, -3B, -3C, - 5, -5B, and -5C Series Turbofan Engines

This amendment adopts a new airworthiness directive (AD) that is applicable to CFM International CFM56-3, -3B, -3C, -5, -5B, and -5C series turbofan engines. This action supersedes telegraphic AD T97-25- 51 that currently requires removal of one engine from an aircraft, and replacement with a serviceable engine or replacement of parts, if both engines are equipped with a specific accessory gearbox (AGB) starter gearshaft or transfer gearbox (TGB) input bevel gear, and daily checks of the AGB/TGB magnetic chip detector. This amendment is prompted by further investigation that has revealed that certain TGB output bevel gears and AGB intermediate gear assemblies on CFM56-3, -3B, and -3C series engines, and AGB gearshaft cluster spur assemblies on CFM56-5, - 5B, and -5C series engines could also be affected. The actions specified by this AD are intended to prevent inflight engine shutdowns due to an AGB starter gearshaft, TGB input bevel gear, TGB output bevel gear, AGB gearshaft cluster spur assembly or AGB intermediate gear assembly failure.