Airworthiness Directive 98-14-51
one-timeAirworthiness Directives; CFM International CFM56-7B Series Turbofan Engines
What this AD requires
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.
Which aircraft AD 98-14-51 applies to
Applies only to engines identified by engine serial number (ESN) in CFMI CFM56-7B Service Bulletin No. 72-130, dated June 29, 1998.
Whether AD 98-14-51 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.
How AD compliance is recorded
A valid compliance record (14 CFR 43.9) states:
Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.
Look up a tail number →Read the full directive (Federal Register)Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.