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Federal Register / Vol. 86, No. 139 / Friday, July 23, 2021 / Proposed Rules
segment assemblies. AD 20210516
requires initial and repetitive replacements of the LPT 4th-stage air sealing ring segment assemblies with parts eligible for installation. AD 2021
0516 also requires initial and repetitive dimensional inspections of the LPT case for bulging and, depending on the results of the dimensional inspections, repair or replacement of the LPT case.
The agency issued AD 20210516 to prevent damage to the LPT 4th-stage air sealing ring segment assemblies, the LPT case, and the LPT 4th-stage blades.
The unsafe condition, if not addressed, could result in uncontained release of the LPT 4th-stage blades, damage to the engine, and damage to the airplane.
Actions Since AD 20210516 Was Issued Since the FAA issued AD 202105
16, the FAA was notified by a manufacturer of parts manufacturer approval PMA parts and that paragraphs c, g, and h of the AD
should include affected PMA part numbers because the unsafe condition also applies to those parts. The FAA

added FAA-approved equivalent part numbers to paragraphs c, g, and h of this AD to include PMA part numbers.
FAAs Determination The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.
Related Service Information Under 1
CFR Part 51
The FAA reviewed Pratt & Whitney Alert Service Bulletin No. PW4G100
A72262, Revision No. 1, dated September 3, 2020 the ASB. The ASB
specifies procedures for replacing the LPT 4th-stage air sealing ring segment assemblies and inspecting the LPT case for bulging. The Director of the Federal Register approved the ASB for incorporation by reference as of May 7, 2021 86 FR 17287, April 2, 2021. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in ADDRESSES.

Proposed AD Requirements in This NPRM
This proposed AD would retain all the requirements of AD 20210516.
This proposed AD would add or FAAapproved equivalent part numbers to paragraph c, Applicability; paragraph g, Required Actions; and paragraph h, Definitions, of this AD. This proposed AD would also add paragraph i, Credit for Previous Actions, allowing operators to take credit for the required actions in paragraph g4 of this AD if, prior to the effective date of this AD, operators performed dimensional inspections of the LPT case for bulging using Pratt & Whitney ASB No. PW4G
100A72262, Original Issue, dated October 22, 2019.
Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect 99
engines installed on airplanes of U.S.
registry.
The FAA estimates the following costs to comply with this proposed AD:

ESTIMATED COSTS
Action
Labor cost
Inspect the LPT case for bulging
Replace the LPT 4th-stage air sealing ring segment assemblies.

2 work-hours $85 per hour = $170
50 work-hours $85 per hour = $4,250

The FAA estimates the following costs to do any necessary repair or replacement that would be required
Parts cost
based on the results of the proposed inspection. The agency has no way of determining the number of aircraft that
$0
64,592

Cost per product $170
68,842

Cost on U.S.
operators $16,830
6,815,358

might need these repairs or replacements.

ON-CONDITION COSTS
Action
Labor cost
Repair LPT case to restore dimensions
Replace the LPT case

250 work-hours $85 per hour = $21,250
0 work-hours $85 per hour = $0

khammond on DSKJM1Z7X2PROD with PROPOSALS

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 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
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16:27 Jul 22, 2021

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aircraft in air commerce by prescribing 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.
Regulatory Findings The FAA determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would not have a substantial direct effect on the
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Parts cost $0
1,300,000

Cost per product $21,250
1,300,000

States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government.
For the reasons discussed above, I
certify that the proposed regulation:
1 Is not a significant regulatory action under Executive Order 12866, 2 Would not affect intrastate aviation in Alaska, and 3 Would not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

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