Airworthiness Directive · Amendment 39-10758 · CFM International CFM56-7B Series Turbofan Engines
CFM International CFM56-7B Series Turbofan Engines
CFM International (CFMI) CFM56-7B series turbofan engines, identified by engine serial number (ESN) in CFMI CFM56-7B Service Bulletin (SB) No. 72-130, dated June 29, 1998. These engines are installed on but not limited to Boeing 737-600, 737-700, and 737-800 series aircraft.
This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) T98-14-51 that was sent previously to all known U.S. owners and operators of CFM International CFM56-7B series turbofan engines by individual telegrams. This AD requires checks of the Accessory Gearbox (AGB)/Transfer Gearbox (TGB) Magnetic Chip Detector (MCD) for abnormal magnetic particles that indicate a pending starter gearshaft failure, and, removal from service of suspect starter gearshafts and replacement with serviceable parts. This amendment is prompted by reports of 2 inflight engine shutdowns due to uncontained failures of the AGB starter gearshafts. The actions specified by this AD are intended to prevent a dual inflight engine shutdown event, which could result in a forced landing and loss of the aircraft.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
