
[Federal Register Volume 88, Number 190 (Tuesday, October 3, 2023)]
[Rules and Regulations]
[Pages 67939-67942]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-21739]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-0940; Project Identifier AD-2022-01521-E; 
Amendment 39-22552; AD 2023-19-02]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Division Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2018-21-
11, which applied to all Pratt & Whitney Division (PW) Model PW4074D, 
PW4077D, PW4084D, PW4090, and PW4090-3 engines with a low-pressure 
compressor (LPC) fan hub, part number (P/N) 51B821 or P/N 52B521, 
installed. AD 2018-21-11 required performing repetitive eddy current 
inspections (ECIs) and fluorescent penetrant inspections (FPIs) for 
cracks in certain LPC fan hubs and removing LPC fan hubs from service 
that fail any inspection. Since the FAA issued AD 2018-21-11, the FAA 
determined that affected LPC fan hub assemblies can meet the published 
certificated life limit without the need for the required repetitive 
FPI inspections in AD 2018-21-11, and the repetitive ECI

[[Page 67940]]

inspections require shortened intervals. Based on a report of another 
incident, the FAA determined that the unsafe condition is likely to 
exist or develop on additional LPC fan hub assemblies and PW model 
engines. This AD expands the applicability to include Model PW4074, 
PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 engines with 
any part number LPC fan hub assembly installed and requires performing 
repetitive ECIs of the LPC fan hub assembly and, depending on the 
results of the inspections, removing the LPC fan hub assembly from 
service. The FAA is issuing this AD to address the unsafe condition on 
these products.

DATES: This AD is effective November 7, 2023.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of November 7, 
2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2023-0940; 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.
    Material Incorporated by Reference:
     For Pratt & Whitney Division service information 
identified in this final rule, contact Pratt & Whitney Division, 400 
Main Street, East Hartford, CT 06118; phone: (860) 565-0140; email: 
[email protected]; website: connect.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 (817) 222-5110. It is 
also available at regulations.gov under Docket No. FAA-2023-0940.

FOR FURTHER INFORMATION CONTACT: Carol Nguyen, Aviation Safety 
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: 
(781) 238-7655; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2018-21-11, Amendment 39-19469 (83 FR 
54663, October 31, 2018) (``AD 2018-21-11''). AD 2018-21-11 applied to 
all PW Model PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and 
PW4090-3 engines. The NPRM published in the Federal Register on May 23, 
2023 (88 FR 32978), which proposed to supersede AD 2018-21-11. The NPRM 
was prompted by an updated analysis by the engine manufacturer, which 
indicated certain LPC fan hubs could crack before their published life 
limit. However, the FAA determined that affected LPC fan hub assemblies 
can meet the published certificated life limit without the need for the 
required repetitive FPI inspections in AD 2018-21-11, and the 
repetitive ECI inspections require shortened intervals. Additionally, 
the FAA also received a report of an uncontained failure of the fan hub 
assembly on an Engine Alliance GP7270 engine on an Air France flight. 
Investigation of this uncontained failure revealed that, due to the 
similarity of design and material processing for the LPC fan hub 
assembly, the ECI inspections should be done on all LPC fan hub 
assembly part numbers installed on PW Model PW4074, PW4074D, PW4077, 
PW4077D, PW4084D, PW4090, and PW4090-3 engines. In the NPRM, the FAA 
proposed to expand the applicability to include Model PW4074, PW4074D, 
PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 engines with any P/N LPC 
fan hub assembly installed. In the NPRM, the FAA also proposed to 
require performing repetitive ECIs of the LPC fan hub assembly and, 
depending on the results of the inspections, removing the LPC fan hub 
assembly from service. The FAA is issuing this AD to prevent failure of 
the LPC fan hub assembly. This condition, if not addressed, could 
result in uncontained debris release, damage to the engine, and damage 
to the aircraft.

Actions Since the NPRM Was Issued

    Since the FAA published the NPRM, PW revised Alert Service Bulletin 
(ASB) PW4G-112-A72-362, Revision No. 1, dated January 20, 2022, to ASB 
PW4G-112-A72-362, Revision No. 2, dated August 2, 2023. This service 
bulletin revision does not include the specification to remove LPC fan 
hub assemblies with reportable indications from service. PW also added 
instructions pertaining to reporting inspection results.
    As a result, the FAA changed paragraph (g)(2) from ``If a 
reportable or rejectable indication is found'' to ``If a rejectable 
indication is found,'' added paragraph (j), Credit for Previous 
Actions, to give full credit for anyone already accomplishing this 
action before the effective date using Revision No. 1, and re-
designated subsequent paragraphs accordingly. This AD does not require 
reporting inspection results.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from two commenters. Commenters included 
The Boeing Company and The Air Line Pilots Association, International. 
Both commenters support 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. Except for minor editorial changes, which 
include updating the service information and removing the requirement 
for removing LPC fan hub assemblies with reportable indications from 
service, this AD is adopted as proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Pratt & Whitney ASB PW4G-112-A72-362, Revision No. 
2, dated August 2, 2023. This service information specifies procedures 
for ECIs of the LPC fan hub assembly for cracks. This service 
information also specifies reporting inspection results to PW.
    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 65 engines installed on 
airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

[[Page 67941]]



                                                 Estimated Costs
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                                                                                    Cost per       Cost on U.S.
               Action                        Labor cost           Parts cost        product         operators
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Perform ECI of LPC fan hub assembly.  14 work-hours x $85 per              $0           $1,190          $77,350
                                       hour = $1,190.
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    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
inspection. The agency has no way of determining the number of engines 
that might need this replacement:

                                               On-Condition Costs
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                   Action                              Labor cost              Parts cost      Cost per product
----------------------------------------------------------------------------------------------------------------
Replace LPC fan hub assembly...............  65 work-hours x $85 per hour       $1,194,000           $1,199,525
                                              = $5,525.
----------------------------------------------------------------------------------------------------------------

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 2018-21-11, Amendment 39-19469 (83 
FR 54663, October 31, 2018); and
0
b. Adding the following new airworthiness directive:

2023-19-02 Pratt & Whitney Division: Amendment 39-22552; Docket No. 
FAA-2023-0940; Project Identifier AD-2022-01521-E.

(a) Effective Date

    This airworthiness directive (AD) is effective November 7, 2023.

(b) Affected ADs

    This AD replaces AD 2018-21-11, Amendment 39-19469 (83 FR 54663, 
October 31, 2018).

(c) Applicability

    This AD applies to all Pratt & Whitney Division Model PW4074, 
PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 engines.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7230, Turbine Engine 
Compressor Section.

(e) Unsafe Condition

    This AD was prompted by an updated analysis by the engine 
manufacturer, which indicated certain low-pressure compressor (LPC) 
fan hubs could crack before their published life limit. We are 
issuing this AD to prevent failure of the LPC fan hub. The unsafe 
condition, if not addressed, could result in uncontained hub 
release, 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) Before accumulating 550 flight cycles (FC) after the 
effective date of this AD, and thereafter at intervals not to exceed 
550 FC since the last eddy current inspection (ECI), perform an ECI 
of the LPC fan hub assembly, in accordance with the Accomplishment 
Instructions, For Engines Installed on Aircraft, paragraph 2., or 
For Engines Not Installed on Aircraft, paragraph 3; of Pratt & 
Whitney Alert Service Bulletin (ASB) PW4G-112-A72-362, Revision No. 
2, dated August 2, 2023 (ASB PW4G-112-A72-362, Revision 2).
    (2) If a rejectable indication is found during the inspections 
required by paragraph (g)(1) of this AD, before further flight, 
replace the LPC fan hub assembly with a part eligible for 
installation.

(h) Installation Prohibition

    After the effective date of this AD, do not install an LPC fan 
hub assembly on any engine, unless it is a part eligible for 
installation as defined in paragraph (k) of this AD.

(i) No Reporting Requirement

    This AD does not require reporting certain information to the 
manufacturer as specified in ASB PW4G-112-A72-362, Revision 2.

(j) Credit for Previous Actions

    Inspections and corrective actions on an engine, accomplished 
before the effective date of this AD in accordance with the 
instructions of Pratt & Whitney ASB PW4G-112-A72-362, Revision No. 
1, dated January 20, 2022, are acceptable to comply with the 
requirements of paragraph (g)(1) of this AD.

[[Page 67942]]

(k) Definitions

    For the purposes of this AD, a ``part eligible for 
installation'' is an affected LPC fan hub assembly that has been 
inspected as required by paragraph (g)(1) of this AD and does not 
have a rejectable or reportable indication or a LPC fan hub assembly 
with zero cycles since new.

(l) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, AIR-520, Continued Operational Safety 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 
(m)(1) of this AD.
    (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.

(m) Additional Information

    (1) For more information about this AD, contact Carol Nguyen, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: (781) 238-7655; email: [email protected].
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (n)(3) and (4) of this AD.

(n) 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 PW4G-112-A72-362, 
Revision No. 2, dated August 2, 2023.
    (ii) [Reserved]
    (3) For service information identified in this AD, contact Pratt 
& Whitney Division, 400 Main Street, East Hartford, CT 06118; phone: 
(860) 565-0140; email: [email protected]; website: 
connect.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 (817) 222-5110.
    (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: www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on September 15, 2023.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-21739 Filed 10-2-23; 8:45 am]
BILLING CODE 4910-13-P


