FAA tweaks fan blade crack hunts on jet engines
Published Date: 7/31/2026
Proposed Rule
Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2018-26-01, which applies to all CFM International, S.A. (CFM) Model CFM56-7B engines. AD 2018-26-01 requires initial and repetitive ultrasonic inspections or eddy current inspections of certain fan blades for crack indications and, depending on the results of the inspections, replacement with parts eligible for installation. Since the FAA issued AD 2018-26-01, CFM issued updated service material providing improvements to the ultrasonic inspection procedures and expanding the inspection area. This proposed AD would require initial and repetitive ultrasonic inspections or eddy current inspections of certain fan blades for crack indications and, depending on the results of the inspections, replacement with parts eligible for installation. The FAA is proposing this AD to address the unsafe condition on these products.
Analyzed Economic Effects
6 provisions identified: 3 benefits, 3 costs, 0 mixed.
Mandatory Fan Blade Inspections
If your airplane uses CFM56-7B engines, the FAA would require initial and repetitive ultrasonic or eddy current inspections of certain fan blades. The rule sets initial inspection timing to before a fan blade reaches 17,000 cycles since new (CSN) or within 1,600 flight cycles (FCs) since the last inspection, whichever is later, and requires repeats at intervals not to exceed 1,600 FCs.
Potential High Replacement Cost On-Condition
If an inspection finds a crack, the AD requires replacing the fan blade before further flight. The FAA estimates an on-condition replacement (fan blade pair) would have labor of 1 work-hour ($85) plus parts costing $208,300, for a total estimated cost of $208,385 per replacement event.
Estimated Inspection Costs for Operators
The FAA estimates this AD would affect 4,553 engines on U.S.-registered airplanes. The agency estimates 2 work-hours per inspection at $85 per hour (labor = $170) and estimates the total cost to U.S. operators for the inspections at $1,548,020.
Installation Eligibility Rule for Fan Blades
After the AD's effective date, you may not install a fan blade on any engine unless the blade is a 'part eligible for installation' — defined as having fewer than 17,000 cycles since new (CSN) or having passed the required inspection within the last 1,600 flight cycles before installation. Removing and reinstalling a blade only for relubrication is excluded.
Reduced Administrative Burden (No Reporting Required)
Where the CFM service bulletin would require reporting inspection results or returning parts to the manufacturer, this proposed AD explicitly does not require those reporting or parts-return actions. Operators may therefore avoid those specific reporting and return obligations under the AD.
Credit for Previously Completed Inspections
You may take credit for inspections already done before the AD's effective date if those inspections used any of a listed set of CFM service bulletins or earlier revisions of the shop manual specified in the AD. This allows previously compliant work to satisfy the AD requirements.
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Key Dates
Department and Agencies
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