[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 [www.gpo.gov]
[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:
     Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: (202) 493-2251.
     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.
     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: [email protected]; website: https://fleetcare.prattwhitney.com. 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 https://www.regulations.gov 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: 
[email protected].

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
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                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
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: [email protected].
    (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: [email protected].
    (2) For service information identified in this AD, contact Pratt 
& Whitney, 400 Main Street, East Hartford, CT 06118; phone: (800) 
565-0140; email: [email protected]; website: https://fleetcare.prattwhitney.com. 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]
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