Proposed Rule2021-18489
Airworthiness Directives; Pratt & Whitney 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
August 27, 2021
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to supersede Airworthiness Directive (AD) 2011-07-02, which applies to all Pratt & Whitney (P&W) JT8D-209, JT8D- 217, JT8D-217A, JT8D-217C, and JT8D-219 model turbofan engines. AD 2011-07-02 requires initial and repetitive torque inspections of the 3rd-stage and 4th-stage low-pressure turbine (LPT) blades. AD 2011-07- 02 also requires replacement of the LPT blade if wear limits are exceeded, replacement of the LPT-to-exhaust case bolts and nuts, and installation of crushable sleeve spacers on the bolts. Since the FAA issued AD 2011-07-02, the FAA received a report of an MD-82 airplane, equipped with a JT8D-217 engine, experiencing an engine surge that resulted in the fracture of an LPT blade. This proposed AD would retain certain requirements of AD 2011-07-02, while revising the inspection thresholds and replacement intervals for the 3rd-stage and 4th-stage LPT blades. 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 164 (Friday, August 27, 2021)</title>
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[Federal Register Volume 86, Number 164 (Friday, August 27, 2021)]
[Proposed Rules]
[Pages 48080-48083]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-18489]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0661; Project Identifier AD-2020-01349-E]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney Turbofan Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2011-07-02, which applies to all Pratt & Whitney (P&W) JT8D-209, JT8D-
217, JT8D-217A, JT8D-217C, and JT8D-219 model turbofan engines. AD
2011-07-02 requires initial and repetitive torque inspections of the
3rd-stage and 4th-stage low-pressure turbine (LPT) blades. AD 2011-07-
02 also requires replacement of the LPT blade if wear limits are
exceeded, replacement of the LPT-to-exhaust case bolts and nuts, and
installation of crushable sleeve spacers on the bolts. Since the FAA
issued AD 2011-07-02, the FAA received a report of an MD-82 airplane,
equipped with a JT8D-217 engine, experiencing an engine surge that
resulted in the fracture of an LPT blade. This proposed AD would retain
certain requirements of AD 2011-07-02, while revising the inspection
thresholds and replacement intervals for the 3rd-stage and 4th-stage
LPT blades. 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 October 12,
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#cda5a8a1bdfff98dbdbfacb9b9baa5a4b9a3a8b4e3aea2a0"><span class="__cf_email__" data-cfemail="f098959c80c2c4b08082918484879899849e9589de939f9d">[email protected]</span></a>; website: <a href="https://fleetcare.prattwhitney.com">https://fleetcare.prattwhitney.com</a>. You may view this 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.
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-2021-0661; 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: Nicholas Paine, Aviation Safety
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803;
phone: (781) 238-7116; fax: (781) 238-7199; email:
<a href="/cdn-cgi/l/email-protection#234d4a404b4c4f42500d490d53424a4d46634542420d444c55"><span class="__cf_email__" data-cfemail="8be5e2e8e3e4e7eaf8a5e1a5fbeae2e5eecbedeaeaa5ece4fd">[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-2021-0661; Project Identifier
AD-2020-01349-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
https://
[[Page 48081]]
www.regulations.gov, including any personal information you provide.
The agency will also post a report summarizing each substantive verbal
contact received 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
Nicholas Paine, 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 2011-07-02, Amendment 39-16639 (76 FR 16526,
March 24, 2011), (AD 2011-07-02), for all P&W JT8D-209, JT8D-217, JT8D-
217A, JT8D-217C, and JT8D-219 model turbofan engines. AD 2011-07-02 was
prompted by nine reports of failure of Tinidur material LPT-to-exhaust
case bolts. AD 2011-07-02 requires initial and repetitive torque
inspections of the 3rd-stage and 4th-stage LPT blades, replacement of
the LPT blade if wear limits are exceeded, and replacement of the LPT-
to-exhaust case bolts and nuts with longer bolts and nuts made of
Tinidur material. AD 2011-07-02 also requires installation of crushable
sleeve spacers on the bolts. The agency issued AD 2011-07-02 to prevent
an LPT blade failure that could result in uncontained engine debris and
damage to the airplane.
Actions Since AD 2011-07-02 Was Issued
Since the FAA issued AD 2011-07-02, the agency received a report of
an MD-82 airplane, equipped with JT8D-217C model turbofan engines that,
on approach to Taipei Songshan Airport, experienced an engine surge on
the number one engine resulting in LPT blade fracture and uncontained
LPT blade failure. An inspection by the manufacturer determined that
this event was caused by shroud notch wear of the LPT blades, which led
to changes in the vibration mode and subsequent high-cycle fatigue of
the airfoil. In addition to this event, the FAA received reports of
five events that involved uncontained failure of the LPT blades on the
affected engines. Based on its investigation of these events, P&W
determined that revised or more restrictive inspection thresholds and
replacement intervals of the 3rd-stage and 4th-stage LPT blades are
necessary and revised its service information accordingly.
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 (ASB) No.
JT8D A6224, Revision No. 7, dated August 26, 2019. This service
information specifies procedures for the initial and repetitive torque
inspections of the 3rd-stage and 4th-stage LPT blades for shroud notch
wear at revised inspection thresholds and intervals. 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.
Other Related Service Information
The FAA reviewed Pratt & Whitney ASB No. JT8D A6494, Revision No.
1, dated January 26, 2010, Pratt & Whitney ASB JT8D A6507, dated
November 2, 2020, and Sections 72-53-12 through 72-53-13 of Pratt &
Whitney Engine Maintenance Manual (EMM), Part No. 773128, Revision 107,
dated October 15, 2020. Pratt & Whitney ASB No. JT8D A6494, Revision
No. 1, dated January 26, 2010, describes procedures for replacing the
LPT-to-exhaust case bolts and nuts and installing the crushable sleeve
spacers. Pratt & Whitney ASB JT8D A6507, dated November 2, 2020,
describes procedures for replacing the 3rd-stage and 4th-stage LPT
blades. Sections 72-53-12 through 72-53-13 of Pratt & Whitney EMM, Part
No. 773128, Revision 107, dated October 15, 2020, describe procedures
for inspecting and repairing the 3rd-stage and 4th-stage LPT blades.
Proposed AD Requirements in This NPRM
This proposed AD would retain certain requirements of AD 2011-07-
02. This proposed AD would require an initial torque inspection of
certain 3rd-stage LPT blades and repetitive torque inspections of 4th-
stage LPT blades for shroud notch wear at revised inspection thresholds
and intervals. This proposed AD would also require replacement of the
3rd-stage and 4th-stage LPT blades before accumulating 5,000 hours
time-in-service.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 42 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
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Inspect 3rd-stage and 4th-stage LPT 1 work-hour x $85 per $0 $85 $3,570
blades. hour = $85.
Replace 3rd-stage and 4th-stage LPT 150 work-hours x $85 per 350,000 362,750 15,235,500
blades. hour = $12,750.
Replace the LPT-to-exhaust case bolts 1.5 work-hours x $85 per 4,576 4,703.50 197,547
and nuts and install the crushable hour = 127.50.
sleeve spacers.
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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.
[[Page 48082]]
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.
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 2011-07-02, Amendment 39-16639
(76 FR 16526, March 24, 2011); and
0
b. Adding the following new airworthiness directive:
Pratt & Whitney: Docket No. FAA-2021-0661; Project Identifier AD-
2020-01349-E.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) action by October 12, 2021.
(b) Affected ADs
This AD replaces AD 2011-07-02, Amendment 39-16639 (76 FR 16526,
March 24, 2011).
(c) Applicability
This AD applies to Pratt & Whitney (P&W) JT8D-209, JT8D-217,
JT8D-217A, JT8D-217C, and JT8D-219 model turbofan engines.
(d) Subject
Joint Aircraft System Component (JASC) Code 7230, Turbine Engine
Compressor Section.
(e) Unsafe Condition
This AD was prompted by a report of an MD-82 airplane, equipped
with a JT8D-217C model turbofan engine, experiencing an engine surge
that resulted in the fracture of the low-pressure turbine (LPT)
blade and uncontained release of the LPT blade. Five prior
uncontained LPT blade failures were also reported on affected model
turbofan engines. The FAA is issuing this AD to prevent LPT blade
fracture and uncontained release of the LPT blade. The unsafe
condition, if not addressed, could result in uncontained engine
debris, damage to the engine, and damage to the aircraft.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
(1) For JT8D-209, JT8D-217, and JT8D-217A model turbofan
engines, within the compliance times specified in the Accomplishment
Instructions, Part 1: JT8D-209, -217, -217A Engines (Part 1),
paragraph 1.A., of P&W Alert Service Bulletin No. JT8D A6224,
Revision No. 7, dated August 26, 2019 (the ASB), perform an initial
torque inspection for shroud notch wear of the 3rd-stage LPT blades
using the procedures in Part 1, paragraph 1, of the ASB.
(i) Thereafter, within the applicable reinspection interval
specified in Table 1--Reinspection Interval for all 3rd Stage
Blades, of the ASB, repeat the torque inspection for shroud notch
wear required by paragraph (g)(1) of this AD.
(ii) If the results of the torque inspection required by
paragraphs (g)(1) or (g)(1)(i) of this AD meet the criteria for
engine removal specified in Table 1--Reinspection Interval for all
3rd Stage Blades, of the ASB, perform piece-part inspections in
accordance with the Instructions for Continued Airworthiness (ICA)
on all 3rd-stage LPT blades before exceeding 20 hours time-in-
service (TIS) since the last torque inspection.
(2) For JT8D-209, JT8D-217, and JT8D-217A model turbofan
engines, within the compliance times specified in Table A or Table
B, of the ASB, as applicable, perform an initial torque inspection
for shroud notch wear of the 4th-stage LPT blades using the
procedures in Part 1, paragraph 1, of the ASB. Wherever the ASB
refers to ``Revision 7 Release Date'' and ``At SB Release Date,''
use the effective date of this AD.
(i) For engines in which the last inspection prior to the
effective date of this AD had a torque inspection result of less
than 15 LB-IN on any 4th-stage LPT blade, perform piece-part
inspections in accordance with the ICA on all 3rd-stage and 4th-
stage LPT blades within 20 hours TIS after the effective date of
this AD.
(ii) Thereafter, within the applicable reinspection interval
specified in Table 2--Reinspection Interval for all 4th Stage
Blades, of the ASB, repeat the torque inspection for shroud notch
wear required by paragraph (g)(2) of this AD.
(iii) If the results of the torque inspection required by
paragraphs (g)(2) or (g)(2)(ii) of this AD meet the criteria for
engine removal specified in Table 2--Reinspection Interval for all
4th Stage Blades, of the ASB, perform piece-part inspections in
accordance with the ICA on all 3rd-stage and 4th-stage LPT blades
before exceeding 20 hours TIS since the last torque inspection.
(3) For JT8D-217C and JT8D-219 model turbofan engines, within
the compliance times specified in Table A or Table B, of the ASB, as
applicable, perform an initial torque inspection for shroud notch
wear of the 4th-stage LPT blades using the procedures in the
Accomplishment Instructions, Part 2: JT8D-217C, -219 Engines (Part
2), paragraph 1, of the ASB. Wherever the ASB refers to ``Revision 7
Release Date'' and ``At SB Release Date,'' use the effective date of
this AD.
(i) For engines in which the last inspection prior to the
effective date of this AD had a torque inspection result of less
than 15 LB-IN on any 4th-stage LPT blade, perform piece-part
inspections in accordance with the ICA on all 3rd-stage and 4th-
stage LPT blades within 20 hours TIS after the effective date of
this AD.
(ii) Thereafter, within the reinspection interval specified in
Table 3-Reinspection Interval for all 4th Stage Blades, of the ASB,
repeat the torque inspection for shroud notch wear required by
paragraph (g)(3) of this AD.
(iii) If the results of the torque inspection required by
paragraph (g)(3) and (g)(3)(ii) of this AD meet the criteria for
engine removal specified in Table 3--Reinspection Interval for all
4th Stage Blades, of the ASB, perform piece-part inspections in
accordance with the ICA on all 3rd-stage and 4th-stage LPT blades
before exceeding 20 hours TIS since the last torque inspection.
(4) At the first engine shop visit after January 1, 2023, or
prior to accumulating 5,000 TIS on the 3rd-stage and 4th-stage LPT
blades, whichever occurs later, but not to exceed 6 years after the
effective date of the AD, replace the 3rd-stage and 4th-stage LPT
blades with parts eligible for installation.
(5) Thereafter, prior to accumulating 5,000 hours TIS on the
3rd-stage and 4th-stage LPT blades since their last replacement,
replace the 3rd-stage and 4th-stage LPT blades with parts eligible
for installation.
(6) After every replacement of the 3rd-stage or 4th-stage LPT
blades, perform initial and repetitive torque inspections of the
3rd-stage or 4th-stage LPT blades using, as applicable, the
accomplishment instructions and
[[Page 48083]]
compliance times in Part 1, paragraph 1, or Part 2, paragraph 1, of
the ASB.
(i) If the results of the torque inspection required by
paragraph (g)(6) of this AD meet the criteria for engine removal
specified in Table 1, 2 or 3, of the ASB, as applicable, perform
piece-part inspections in accordance with the ICA on all 3rd-stage
and 4th-stage LPT blades before exceeding 20 hours TIS since the
last torque inspection.
(ii) [Reserved]
(7) The initial inspection or the reinspection interval should
not be reset unless the blades are refurbished. Whenever a used
blade is reinstalled in a rotor, the previous used time should be
subtracted from the initial inspection threshold.
(8) Whenever a refurbished or used blade is intermixed with zero
hours time-since-new (TSN) blades in a rotor, use the lowest initial
inspection threshold that is applicable.
(9) At the next accessibility to the LPT-to-exhaust case bolts
and nuts after the effective date of this AD, do the following:
(i) Replace the bolts with part number (P/N) MS9557-26 bolts;
(ii) Replace the nuts with P/N 375095 nuts or P/N 490270 nuts;
and
(iii) Install crushable sleeve spacers, P/N 822903, under the
head of the bolts.
Note 1 to paragraph (g): Guidance on replacing the 3rd-stage and
4th-stage LPT blades can be found in P&W ASB JT8D A6507, dated
November 2, 2020.
Note 2 to paragraph (g): Guidance on replacing the LPT-to-
exhaust case bolts and nuts and installing the crushable sleeve
spacers can be found in P&W ASB No. JT8D A6494, Revision No. 1,
dated January 26, 2010.
(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, except that the separation of engine flanges
solely for the purposes of transportation without subsequent engine
maintenance does not constitute an engine shop visit.
(2) Accessibility to the LPT-to-exhaust case bolts refers to
maintenance involving the inner turbine fan ducts being removed from
the engine.
(3) Parts eligible for installation are 3rd-stage or 4th-stage
LPT blades with less than 5,000 hours TIS.
(4) A ``piece-part inspection'' is when the blades are removed
from the rotor.
(5) A ``used blade'' refers to a 3rd-stage or 4th-stage LPT
blade that has more than zero hours TSN.
(i) Credit for Previous Actions
You may take credit for any initial torque inspection for shroud
notch wear required by paragraphs (g)(1) through (3) of this AD if
you performed the initial inspection before the effective date of
this AD using P&W ASB No. JT8D A6224, Revision No. 5, dated June 11,
2004, or Revision No. 6, dated May 3, 2007.
(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
ECO Branch, send it to the attention of the person identified in
Related Information. You may email your request to: <a href="/cdn-cgi/l/email-protection#3b7a757e167a7f167a7674787b5d5a5a155c544d"><span class="__cf_email__" data-cfemail="0a4b444f274b4e274b4745494a6c6b6b246d657c">[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 Nicholas Paine,
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue,
Burlington, MA 01803; phone: (781) 238-7116; fax: (781) 238-7199;
email: <a href="/cdn-cgi/l/email-protection#1977707a717675786a377337697870777c597f7878377e766f"><span class="__cf_email__" data-cfemail="3a5453595255565b491450144a5b53545f7a5c5b5b145d554c">[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#1179747d612325516163706565667978657f74683f727e7c"><span class="__cf_email__" data-cfemail="452d2029357771053537243131322d2c312b203c6b262a28">[email protected]</span></a>; website: <a href="https://fleetcare.prattwhitney.com">https://fleetcare.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 August 5, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification
Service.
[FR Doc. 2021-18489 Filed 8-26-21; 8:45 am]
BILLING CODE 4910-13-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.