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

This amendment adopts a new airworthiness directive (AD) that is applicable to CFM International, S.A. CFM56-3, -3B, and -3C series turbofan engines. This amendment requires that use of certain lubricants no longer on the manufacturer's approved list be discontinued. In addition, this amendment requires a one-time fan disk dovetail wear measurement, and if wear exceeds certain limits, requires an ultrasonic inspection for cracks in the fan disk, and, if necessary, removal from service of fan disks and replacement with serviceable parts. This amendment is prompted by reports of fan disk heavy wear and cracks. The actions specified by this amendment are intended to prevent fan disk failure, which could result in an uncontained engine failure and damage to the aircraft.