Proposed Rule2021-15518
Airworthiness Directives; Pratt & Whitney Division Turbofan Engines
Primary source
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Published
July 23, 2021
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to supersede Airworthiness Directive (AD) 2021-05-16, which applies to certain Pratt & Whitney Division (PW) PW4164, PW4164-1D, PW4168, PW4168-1D, PW4168A, PW4168A-1D, and PW4170 model turbofan engines. AD 2021-05-16 requires 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 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. Since the FAA issued AD 2021-05-16, the FAA was notified of an inadvertent omission in the LPT 4th-stage air sealing ring segment assembly part numbers. This proposed AD would correct this omission. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 86 Issue 139 (Friday, July 23, 2021)</title>
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[Federal Register Volume 86, Number 139 (Friday, July 23, 2021)]
[Proposed Rules]
[Pages 38941-38943]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-15518]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
========================================================================
Federal Register / Vol. 86, No. 139 / Friday, July 23, 2021 /
Proposed Rules
[[Page 38941]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0577; Project Identifier AD-2021-00470-E]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney Division Turbofan
Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
-----------------------------------------------------------------------
SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2021-05-16, which applies to certain Pratt & Whitney Division (PW)
PW4164, PW4164-1D, PW4168, PW4168-1D, PW4168A, PW4168A-1D, and PW4170
model turbofan engines. AD 2021-05-16 requires 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 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. Since
the FAA issued AD 2021-05-16, the FAA was notified of an inadvertent
omission in the LPT 4th-stage air sealing ring segment assembly part
numbers. This proposed AD would correct this omission. The FAA is
proposing this AD to address the unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by September
7, 2021.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the instructions for submitting comments.
<bullet> Fax: (202) 493-2251.
<bullet> Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
<bullet> Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
For service information identified in this NPRM, contact Pratt &
Whitney, 400 Main Street, East Hartford, CT 06118; phone: (800) 565-
0140; email: <a href="/cdn-cgi/l/email-protection#9df5f8f1edafa9ddedeffce9e9eaf5f4e9f3f8e4b3fef2f0"><span class="__cf_email__" data-cfemail="a7cfc2cbd79593e7d7d5c6d3d3d0cfced3c9c2de89c4c8ca">[email protected]</span></a>; website: <a href="https://prattwhitney.com">https://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.
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 NPRM, any comments
received, and other information. The street address for Docket
Operations is listed above.
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#2b484a59444705454c5e524e456b4d4a4a054c445d"><span class="__cf_email__" data-cfemail="335052415c5f1d5d54464a565d735552521d545c45">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include ``Docket No. FAA-2021-0577; Project Identifier
AD-2021-00470-E'' at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
the proposal because of those comments.
Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
<a href="https://www.regulations.gov">https://www.regulations.gov</a>, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact the FAA receives about this proposed AD.
Confidential Business Information
CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as ``PROPIN.'' The FAA will treat such marked submissions as
confidential under the FOIA, and they will not be placed in the public
docket of this NPRM. Submissions containing CBI should be sent to Carol
Nguyen, Aviation Safety Engineer, ECO Branch, FAA, 1200 District
Avenue, Burlington, MA 01803. Any commentary that the FAA receives
which is not specifically designated as CBI will be placed in the
public docket for this rulemaking.
Background
The FAA issued AD 2021-05-16, Amendment 39-21459 (86 FR 17287,
April 2, 2021), (AD 2021-05-16), for 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. AD 2021-05-16 was
prompted by 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
[[Page 38942]]
segment assemblies. AD 2021-05-16 requires initial and repetitive
replacements of the LPT 4th-stage air sealing ring segment assemblies
with parts eligible for installation. AD 2021-05-16 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 2021-05-16
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 2021-05-16 Was Issued
Since the FAA issued AD 2021-05-16, 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.
FAA's 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. 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.
Proposed AD Requirements in This NPRM
This proposed AD would retain all the requirements of AD 2021-05-
16. This proposed AD would add ``or FAA-approved 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 (g)(4)
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-100-A72-262, 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
----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost product operators
----------------------------------------------------------------------------------------------------------------
Inspect the LPT case for bulging...... 2 work-hours x $85 per $0 $170 $16,830
hour = $170.
Replace the LPT 4th-stage air sealing 50 work-hours x $85 per 64,592 68,842 6,815,358
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 proposed
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
----------------------------------------------------------------------------------------------------------------
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 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 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.
[[Page 38943]]
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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 AD 2021-05-16, Amendment 39-21459
(86 FR 17287, April 2, 2021); and
0
b. Adding the following new airworthiness directive:
Pratt & Whitney Division: Docket No. FAA-2021-0577; Project
Identifier AD-2021-00470-E.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) action by September 7, 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 paragraphs (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 No. 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 Related Information. Information may be emailed to:
<a href="/cdn-cgi/l/email-protection#f9b8b7bcd4b8bdd4b8b4b6bab99f9898d79e968f"><span class="__cf_email__" data-cfemail="266768630b67620b676b69656640474708414950">[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
(1) 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#5d3e3c2f323173333a282438331d3b3c3c733a322b"><span class="__cf_email__" data-cfemail="aecdcfdcc1c280c0c9dbd7cbc0eec8cfcf80c9c1d8">[email protected]</span></a>.
(2) For 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#573f323b276563172725362323203f3e2339322e7934383a"><span class="__cf_email__" data-cfemail="fa929f968ac8ceba8a889b8e8e8d92938e949f83d4999597">[email protected]</span></a>; website: <a href="https://prattwhitney.com">https://prattwhitney.com</a>. You may view this referenced service information
at the 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.
Issued on July 16, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification
Service.
[FR Doc. 2021-15518 Filed 7-22-21; 8:45 am]
BILLING CODE 4910-13-P
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