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

This amendment adopts a new airworthiness directive (AD) that is applicable to CFM International (CFMI) CFM56-3, -3B, and -3C series turbofan engines. This action requires, on aircraft with two affected engines installed, removal of one affected engine from an aircraft, and replacement with a serviceable engine, or replacement of a suspect accessory gearbox (AGB) starter gearshaft with a serviceable gearshaft within 350 hours time in service (TIS) after the effective date of this AD, or by September 1, 1998, whichever occurs first. This action also requires, on aircraft with only one affected engine installed, removal of the affected engine from the aircraft, and replacement with a serviceable engine , or replacement of thea suspect starter gearshaft with a serviceable gearshaft within 2,100 hours TIS after the effective date of this AD, or by February 1, 1999, whichever occurs first. This amendment is prompted by reports of two inflight engine shutdowns caused by an AGB starter gearshaft failure. The actions specified in this AD are intended to prevent an AGB starter gearshaft failure, which can result in an inflight engine shutdown, and on aircraft with two affected engines installed, possible dual inflight engine shutdown and forced landing.