Federal Register - July 23, 2021
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Source: Federal Register
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Federal Register / Vol. 86, No. 139 / Friday, July 23, 2021 / Rules and Regulations Request To Revise References to Engine Manual Boeing requested that the FAA update reference to the service information in the Related Service Information section of the NPRM by referencing Revision 90
of the GE CF680A Engine Manual and Revision 91 of the CF680C2 Engine Manual. These revisions of the respective engines manuals include updated procedures regarding HPT rotor Stage 1 and Stage 2 disk serviceability for these model engines with respect to HPT thermal shield inspection findings.
The FAA agrees and has updated the Related Service Information section of this AD as suggested by the commenter.
Request To Clarify Inspection Instructions Delta requested that the FAA clarify that the mandated visual and FPI
inspections should be accomplished in accordance with the engine manual for the affected engine models.
The FAA disagrees. Operators may use any approved method to perform the visual and FPI inspections required by this AD.
Request To Clarify Engine Applicability United requested that the FAA
remove CF680C2B8F model turbofan engines from the applicability of this AD. United commented that two HPT
thermal shield configurations exist, part
number P/N 2787M85P01 and P/N
9315M41P20. Neither of these configurations are applicable to the R88DT HPT rotor installed on CF6
80C2B8F model turbofan engines.
United requested that if the FAA
considers the CF680C2B8F turbofan engine model affected by this AD, then the applicable engine manual should be updated to reflect the inspections required by this AD.
The FAA agrees. This AD is not applicable to the R88DT HPT rotor installed on CF680C2B8F model turbofan engines because that rotor configuration does not have an affected thermal shield. The FAA added the applicable part numbers for HPT
thermal shields installed on CF680A
and CF680C2 model turbofan engines to the applicability paragraph of this AD.
Support for the NPRM
ALPA supported the NPRM without change.
Conclusion The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed.
Accordingly, the FAA is issuing this AD
to address the unsafe condition on these products. Except for minor editorial changes and any other changes described previously, this AD is
adopted as proposed in the NPRM.
None of the changes will increase the economic burden on any operator.
Related Service Information The FAA reviewed ESM 725300
High Pressure Turbine Rotor AssemblyDisassembly CF680A ESM
725300, dated February 15, 2020
from the GE CF680A Engine Manual GEK72501Rev 90, dated February 15, 2021. CF680A ESM 725300
describes procedures for the removal of the HPT thermal shield, the HPT rotor stage 1 disk, and the HPT rotor stage 2
disk installed on CF680A model turbofan engines.
The FAA also reviewed ESM 7253
00 High Pressure Turbine Rotor AssemblyDisassembly CF680C2
ESM 725300, dated December 1, 2019 from the GE CF680C2 Engine Manual GEK92451Rev 91, dated December 1, 2020. CF680C2 ESM 72
5300 describes procedures for the removal of the HPT thermal shield, the HPT rotor stage 1 disk, and the HPT
rotor stage 2 disk installed on CF680C2
model turbofan engines.
Costs of Compliance The FAA estimates that this AD
affects 1,084 engines installed on airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD:
ESTIMATED COSTS
Action
Labor cost
Perform FPI and visual inspection of HPT
thermal shield.
2 work-hours $85 per hour = $170
The FAA estimates the following costs to do any necessary replacements that would be required based on the
Cost per product
Parts cost
results of the inspection. The agency has no way of determining the number of
$0
Cost on U.S.
operators
$170
$184,280
aircraft that might need these replacements.
ON-CONDITION COSTS
Action
Labor cost
Replace HPT thermal shield
Replace HPT rotor stage 1 disk
Replace HPT rotor stage 2 disk
2 work-hours $85 per hour = $170
2 work-hours $85 per hour = $170
2 work-hours $85 per hour = $170
khammond on DSKJM1Z7X2PROD with RULES
Authority for This Rulemaking Title 49 of the United States Code specifies the FAAs authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII:
Aviation Programs, describes in more
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18:24 Jul 22, 2021
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detail the scope of the Agencys authority.
The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA
with promoting safe flight of civil aircraft in air commerce by prescribing
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Parts cost $209,600
799,700
364,600
Cost per product $209,770
799,870
364,770
regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce.
This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.
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23JYR1
