Rule2021-24574
Airworthiness Directives; Pratt & Whitney Division Turbofan Engines
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
November 12, 2021
Effective
December 17, 2021
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is superseding Airworthiness Directive (AD) 2021-05-16 for certain Pratt & Whitney Division (PW) PW4164, PW4164-1D, PW4168, PW4168-1D, PW4168A, PW4168A-1D, and PW4170 model turbofan engines. AD 2021-05-16 required initial and repetitive replacements of the low- pressure turbine (LPT) 4th-stage air sealing ring segment assemblies with parts eligible for installation. AD 2021-05-16 also required 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. This AD was prompted by notification to the FAA of an inadvertent omission in the LPT 4th-stage air sealing ring segment assembly part numbers. This AD requires initial and repetitive replacements of the LPT 4th-stage air sealing ring segment assemblies with parts eligible for installation. This AD 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 FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 86 Issue 216 (Friday, November 12, 2021)</title>
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[Federal Register Volume 86, Number 216 (Friday, November 12, 2021)]
[Rules and Regulations]
[Pages 62717-62719]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-24574]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0577; Project Identifier AD-2021-00470-E;
Amendment 39-21787; AD 2021-22-14]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney Division Turbofan
Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2021-05-16
for certain Pratt & Whitney Division (PW) PW4164, PW4164-1D, PW4168,
PW4168-1D, PW4168A, PW4168A-1D, and PW4170 model turbofan engines. AD
2021-05-16 required initial and repetitive replacements of the low-
pressure turbine (LPT) 4th-stage air sealing ring segment assemblies
with parts eligible for installation. AD 2021-05-16 also required
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. This AD was prompted by
notification to the FAA of an inadvertent omission in the LPT 4th-stage
air sealing ring segment assembly part numbers. This AD requires
initial and repetitive replacements of the LPT 4th-stage air sealing
ring segment assemblies with parts eligible for installation. This AD
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 FAA is issuing
this AD to address the unsafe condition on these products.
DATES: This AD is effective December 17, 2021.
The Director of the Federal Register approved the incorporation by
reference of a certain other publication listed in this AD as of May 7,
2021 (86 FR 17287, April 2, 2021).
ADDRESSES: For service information identified in this final rule,
contact Pratt & Whitney Division, 400 Main Street, East Hartford, CT
06118; phone: (800) 565-0140; email: <a href="/cdn-cgi/l/email-protection#fb939e978bc9cfbb8b8cd58e8f98d5989496"><span class="__cf_email__" data-cfemail="b0d8d5dcc08284f0c0c79ec5c4d39ed3dfdd">[email protected]</span></a>; website:
<a href="https://fleetcare.prattwhitney.com">https://fleetcare.prattwhitney.com</a>. You may view this service
information at the Airworthiness Products Section, Operational Safety
Branch, FAA, 1200 District Avenue, Burlington, MA 01803. For
information on the availability of this material at the FAA, call (781)
238-7759. It is also available at <a href="https://www.regulations.gov">https://www.regulations.gov</a> by
searching for and locating Docket No. FAA-2021-0577.
Examining the AD Docket
You may examine the AD docket at <a href="https://www.regulations.gov">https://www.regulations.gov</a> by
searching for and locating Docket No. FAA-2021-0577; or in person at
Docket Operations between 9 a.m. and 5 p.m., Monday through Friday,
except Federal holidays. The AD docket contains this final rule, any
comments received, and other information. The address for Docket
Operations is U.S. Department of Transportation, Docket Operations, M-
30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue
SE, Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: Carol Nguyen, Aviation Safety
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803;
phone: (781) 238-7655; fax: (781) 238-7199; email:
<a href="/cdn-cgi/l/email-protection#f09391829f9cde9e978589959eb0969191de979f86"><span class="__cf_email__" data-cfemail="46252734292a682821333f23280620272768212930">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Background
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to supersede AD 2021-05-16, Amendment 39-21459 (86 FR
17287, April 2, 2021), (AD 2021-05-16). AD 2021-05-16 applied to
certain PW PW4164, PW4164-1D, PW4168, PW4168-1D, PW4168A, PW4168A-1D,
and PW4170 model turbofan engines with LPT 4th-stage air sealing ring
segment assemblies, part number (P/N) 50N463-01 or P/N 50N526-01,
installed. The NPRM published in the Federal Register on July 23, 2021
(86 FR 38941). The NPRM was prompted by notification from a
manufacturer of parts manufacturer approval (PMA) parts that AD 2021-
05-16 should include affected PMA part numbers because the unsafe
condition also applies to those parts. AD 2021-05-16 resulted from six
reports from the manufacturer concerning LPT 4th-stage vane cluster
assemblies leaning back and notching into rotating LPT 4th-stage
blades, causing some blades to fracture and release. These incidents
resulted in an aborted takeoff, air turnbacks, engine surges, high
vibrations, and unplanned engine removals. The incidents were
attributed to the LPT 4th-stage air sealing ring segment assemblies
moving into the LPT 4th-stage blades knife edge seals, resulting in
damage to the ring segment assemblies. In the NPRM, the FAA proposed to
require initial and repetitive replacements of the LPT 4th-stage air
sealing ring segment assemblies with parts eligible for installation.
In the
[[Page 62718]]
NPRM, the FAA also proposed to require 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.
Discussion of Final Airworthiness Directive
Comments
The FAA received comments from one commenter, the Air Line Pilots
Association (ALPA). ALPA supported the NPRM without change.
Conclusion
The FAA reviewed the relevant data, considered the comments
received, and determined that air safety requires adopting the AD as
proposed. Accordingly, the FAA is issuing this AD to address the unsafe
condition on these products. This AD is adopted as proposed in the
NPRM.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Pratt & Whitney Alert Service Bulletin No. PW4G-
100-A72-262, 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.
Costs of Compliance
The FAA estimates that this AD affects 99 engines installed on
airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD:
Estimated Costs
----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Inspect the LPT case for bulging... 2 work-hours x $85 per hour $0 $170 $16,830
= $170.
Replace the LPT 4th-stage air 50 work-hours x $85 per 64,592 68,842 6,815,358
sealing ring segment assemblies. hour = $4,250.
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The FAA estimates the following costs to do any necessary repair or
replacement that would be required based on the results of the
inspection. The agency has no way of determining the number of aircraft
that might need these repairs or replacements.
On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Cost per
Action Labor cost Parts cost product
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Repair LPT case to restore dimensions......... 250 work-hours x $85 per hour = $0 $21,250
$21,250.
Replace the LPT case.......................... 0 work-hours x $85 per hour = $0 1,300,000 1,300,000
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Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's 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 Agency's 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 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 has determined that this AD will not have federalism
implications under Executive Order 13132. This AD will not have a
substantial direct effect on the 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 this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Will not affect intrastate aviation in Alaska, and
(3) Will not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
The Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
0
2. The FAA amends Sec. 39.13 by:
0
a. Removing Airworthiness Directive 2021-05-16, Amendment 39-21459 (86
FR 17287, April 2, 2021); and
0
b. Adding the following new airworthiness directive:
2021-22-14 Pratt & Whitney Division: Amendment 39-21787; Docket No.
FAA-2021-0577; Project Identifier AD-2021-00470-E.
[[Page 62719]]
(a) Effective Date
This airworthiness directive (AD) is effective December 17,
2021.
(b) Affected ADs
This AD replaces AD 2021-05-16, Amendment 39-21459 (86 FR 17287,
April 2, 2021).
(c) Applicability
This AD applies to Pratt & Whitney Division (PW) PW4164, PW4164-
1D, PW4168, PW4168-1D, PW4168A, PW4168A-1D, and PW4170 model
turbofan engines with low-pressure turbine (LPT) 4th-stage air
sealing ring segment assemblies, part number (P/N) 50N463-01, P/N
50N526-01, or FAA-approved equivalent part numbers, installed.
(d) Subject
Joint Aircraft System Component (JASC) Code 7250, Turbine
Section.
(e) Unsafe Condition
This AD was prompted by several reports from the manufacturer
concerning LPT 4th-stage vane cluster assemblies leaning back and
notching into the rotating LPT 4th-stage blades, causing some blades
to fracture and release. A manufacturer investigation into those
reports determined that the leaning back of the LPT 4th-stage vane
cluster assemblies was caused by damage to the LPT 4th-stage air
sealing ring segment assemblies. The FAA is issuing this AD 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.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
(1) For affected engines that have either the Talon IIA outer
combustion chamber assembly, P/N 51J100 or P/N 51J382, or the Talon
IIB outer combustion chamber assembly, P/N 51J381 or P/N 51J500,
installed, at the next engine shop visit after the effective date of
this AD, remove from service the LPT 4th-stage air sealing ring
segment assemblies, P/N 50N463-01, P/N 50N526-01, or FAA-approved
equivalent part numbers, and replace with parts eligible for
installation.
(2) For affected engines not referenced in paragraph (g)(1) of
this AD, at the next LPT overhaul after the effective date of this
AD, remove from service the LPT 4th-stage air sealing ring segment
assemblies, P/N 50N463-01, P/N 50N526-01, or FAA-approved equivalent
part numbers, and replace with parts eligible for installation.
(3) For all affected engines, at each LPT overhaul after
compliance with the required actions in paragraph (g)(1) or (2) of
this AD, remove from service the LPT 4th-stage air sealing ring
segment assemblies, P/N 50N526-01 or FAA-approved equivalent part
numbers, and replace with parts eligible for installation.
(4) During each replacement of the LPT 4th-stage air sealing
ring segment assemblies required by paragraphs (g)(1) through (3) of
this AD, perform a dimensional inspection of the LPT case for
bulging in accordance with the Accomplishment Instructions,
paragraph 2, of PW Alert Service Bulletin No. PW4G-100-A72-262
Revision No. 1, dated September 3, 2020 (the ASB).
(5) If, during the dimensional inspection of the LPT case
required by paragraph (g)(4) of this AD, any LPT case found to be
outside the serviceable limits specified in Table 1: Serviceable
Limits and Repairs of the ASB, repair or replace the LPT case before
further flight.
(h) Definitions
For the purpose of this AD:
(1) An ``engine shop visit'' is the induction of an engine into
the shop for maintenance involving the separation of pairs of major
mating engine flanges H through P. The separation of engine flanges
solely for the purpose of transportation without subsequent engine
maintenance does not constitute an engine shop visit.
(2) An ``LPT overhaul'' is when the LPT rotor is removed from
the engine, all four disks are removed from the LPT rotor, and all
blades are removed from the disks.
(3) ``Parts eligible for installation'' are LPT 4th-stage air
sealing ring segment assemblies, P/N 50N526-01, or FAA-approved
equivalent part numbers, with zero flight cycles since new or with a
P/N not mentioned in this AD.
(i) Credit for Previous Actions
You may take credit for the dimensional inspection of the LPT
case for bulging required by paragraph (g)(4) of this AD if the
inspection was performed before the effective date of this AD using
PW ASB PW4G-100-A72-262 Original Issue, dated October 22, 2019.
(j) Alternative Methods of Compliance (AMOCs)
(1) The Manager, ECO Branch, FAA, has the authority to approve
AMOCs for this AD, if requested using the procedures found in 14 CFR
39.19. In accordance with 14 CFR 39.19, send your request to your
principal inspector or local Flight Standards District Office, as
appropriate. If sending information directly to the manager of the
certification office, send it to the attention of the person
identified in paragraph (k) of this AD. Information may be emailed
to: <a href="/cdn-cgi/l/email-protection#d998979cf4989df49894969a99bfb8b8f7beb6af"><span class="__cf_email__" data-cfemail="c1808f84ec8085ec808c8e8281a7a0a0efa6aeb7">[email protected]</span></a>.
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the local flight standards district office/certificate holding
district office.
(k) Related Information
For more information about this AD, contact Carol Nguyen,
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue,
Burlington, MA 01803; phone: (781) 238-7655; fax: (781) 238-7199;
email: <a href="/cdn-cgi/l/email-protection#781b190a171456161f0d011d16381e1919561f170e"><span class="__cf_email__" data-cfemail="c5a6a4b7aaa9ebaba2b0bca0ab85a3a4a4eba2aab3">[email protected]</span></a>.
(l) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference (IBR) of the service information listed
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do
the actions required by this AD, unless the AD specifies otherwise.
(3) The following service information was approved for IBR on
May 7, 2021 (86 FR 17287, April 2, 2021).
(i) Pratt & Whitney Alert Service Bulletin No. PW4G-100-A72-262,
Revision No. 1, dated September 3, 2020.
(ii) [Reserved]
(4) For Pratt & Whitney service information identified in this
AD, contact Pratt & Whitney, 400 Main Street, East Hartford, CT
06118; phone: (800) 565-0140; email: <a href="/cdn-cgi/l/email-protection#6008050c1052542010174e1514034e030f0d"><span class="__cf_email__" data-cfemail="2b434e475b191f6b5b5c055e5f4805484446">[email protected]</span></a>; website:
<a href="https://fleetcare.prattwhitney.com">https://fleetcare.prattwhitney.com</a>.
(5) You may view this service information at FAA, Airworthiness
Products Section, Operational Safety Branch, 1200 District Avenue,
Burlington, MA 01803. For information on the availability of this
material at the FAA, call (781) 238-7759.
(6) You may view this service information that is incorporated
by reference at the National Archives and Records Administration
(NARA). For information on the availability of this material at
NARA, email: <a href="/cdn-cgi/l/email-protection#aaccd884c3c4d9dacfc9dec3c5c4eac4cbd8cb84cdc5dc"><span class="__cf_email__" data-cfemail="8bedf9a5e2e5f8fbeee8ffe2e4e5cbe5eaf9eaa5ece4fd">[email protected]</span></a>, or go to: <a href="https://www.archives.gov/federal-register/cfr/ibr-locations.html">https://www.archives.gov/federal-register/cfr/ibr-locations.html</a>.
Issued on October 15, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification
Service.
[FR Doc. 2021-24574 Filed 11-10-21; 8:45 am]
BILLING CODE 4910-13-P
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