Airworthiness Directives; Pratt & Whitney Turbofan Engines

[Federal Register Volume 86, Number 223 (Tuesday, November 23, 2021)]
[Rules and Regulations]
[Pages 66444-66447]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-25500]


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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; 
Amendment 39-21792; AD 2021-22-19]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2011-07-02 
for all Pratt & Whitney (P&W) JT8D-209, JT8D-217, JT8D-217A, JT8D-217C, 
and JT8D-219 model turbofan engines. AD 2011-07-02 required initial and 
repetitive torque inspections of the 3rd-stage and 4th-stage low-
pressure turbine (LPT) blades. AD 2011-07-02 also required 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. 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 LPT blade and 
uncontained release of the LPT blade. This AD retains 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 issuing this AD to address the unsafe condition on these 
products.

DATES: This AD is effective December 28, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of December 28, 
2021.

ADDRESSES: For service information identified in this final rule, 
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. It is 
also available at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2021-0661.

[[Page 66445]]

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 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: 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:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2011-07-02, Amendment 39-16639 (76 FR 
16526, March 24, 2011), (AD 2011-07-02). AD 2011-07-02 applied to all 
P&W JT8D-209, JT8D-217, JT8D-217A, JT8D-217C, and JT8D-219 model 
turbofan engines. The NPRM published in the Federal Register on August 
27, 2021 (86 FR 48080). The NPRM was prompted by 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. In the NPRM, 
the FAA proposed to 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. In the NPRM, the FAA also proposed to require replacement of 
the 3rd-stage and 4th-stage LPT blades before accumulating 5,000 hours 
time-in-service.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from one commenter. The Boeing Company 
supported the NPRM without change.

Conclusion

    The FAA reviewed the relevant data, considered the comment 
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 (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.

Costs of Compliance

    The FAA estimates that this AD affects 42 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
----------------------------------------------------------------------------------------------------------------
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.
----------------------------------------------------------------------------------------------------------------

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

[[Page 66446]]

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 AD 2011-07-02, Amendment 39-16639 
(76 FR 16526, March 24, 2011); and
0
b. Adding the following new airworthiness directive:

2021-22-19 Pratt & Whitney: Amendment 39-21792; Docket No. FAA-2021-
0661; Project Identifier AD-2020-01349-E.

(a) Effective Date

    This airworthiness directive (AD) is effective December 28, 
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 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.

[[Page 66447]]

    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 
paragraph (k) of this AD. 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

    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].

(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.
    (i) Pratt & Whitney Alert Service Bulletin No. JT8D A6224, 
Revision No. 7, dated August 26, 2019.
    (ii) [Reserved]
    (3) 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.
    (4) 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.
    (5) 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: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on October 21, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-25500 Filed 11-22-21; 8:45 am]
BILLING CODE 4910-13-P

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