CFM LEAP-1B Engines Face FAA Part Replacement Mandates
Published Date: 4/15/2025
Proposed Rule
Summary
The FAA wants to update safety rules for certain CFM LEAP-1B jet engines because some parts might be weaker due to iron in the material. This means more engine parts need replacing to keep flights safe. If you own or operate these engines, get ready to act before the comment deadline on May 30, 2025, to avoid risks and extra costs later.
Analyzed Economic Effects
5 provisions identified: 1 benefits, 4 costs, 0 mixed.
Mandatory HPT Disk Replacements for U.S. Engines
The FAA would require replacement of certain high-pressure turbine (HPT) rotor stage 1 disks. The agency estimates this would affect 51 LEAP-1B engines on U.S. registry, with labor of 8 work-hours and parts cost listed as $215,635 (pro-rated) for a total estimated cost per engine of $216,315 and a total cost to U.S. operators of $11,032,065.
Applicability Expanded to More HPT Disks
The proposed AD expands applicability to include additional HPT rotor stage 1 disks identified in CFM Service Bulletin LEAP-1B-72-00-0402-01A-930A-D, Issue 001, dated January 23, 2024. For those disks, you must remove and replace the disk at the next piece-part exposure or before exceeding the cycles-since-new (CSN) threshold identified in the service bulletin, or within 50 flight cycles if the CSN threshold was already exceeded as of the AD's effective date.
Prohibition on Installing Affected Parts
After the effective date of the AD, you may not install any HPT rotor stage 1 disk or compressor rotor stages 6–10 spool that has a part number and serial number listed in the applicable CFM service bulletins. The prohibition applies to parts identified in Compliance, paragraph 3.E., Tables in CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 002 and CFM SB LEAP-1B-72-00-0402-01A-930A-D, Issue 001.
Compressor Spool Replacement Requirement Retained
The proposed AD retains the requirement to replace a certain compressor rotor stages 6–10 spool when identified by part and serial number in the service bulletin. The FAA estimates the cost per spool replacement at $38,340 (8 work-hours plus $37,660 parts), and states there are currently no engines on U.S. registry that require this spool replacement.
Credit for Prior Compliant Replacements
The proposed AD gives credit for actions done before January 16, 2024, if those replacements followed the Accomplishment Instructions in CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 001, dated March 7, 2023. If you replaced affected parts following that earlier service bulletin before January 16, 2024, you get credit and do not have to repeat those actions to comply with paragraph (g) of this AD.
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