Summary
The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to CFM International, S.A. CFM56-2C, -3, and -5 series turbofan engines. This proposal would require removing from service main fuel pumps with bronze bearings and installing main fuel pumps with aluminum/bronze alloy bearings. This proposal is prompted by several reports of indications of wear and failures of main fuel pump bronze bearings. The actions specified by the proposed AD are intended to prevent failures of main fuel pump bearings, resulting in fuel filter clogging, fuel flow degradation, fuel manifold and nozzle clogging resulting in diminished in-flight restart capability, low pressure turbine (LPT) case burn-through, inability to obtain a successful engine start, and damage to the airplane.