
[Federal Register Volume 88, Number 222 (Monday, November 20, 2023)]
[Rules and Regulations]
[Pages 80572-80575]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-25524]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-1638; Project Identifier AD-2022-00466-E; 
Amendment 39-22586; AD 2023-22-02]
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) 2018-02-
10, which applied to certain Pratt & Whitney Division (PW) Model 
PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 
engines. AD 2018-02-10 required performing repetitive fluorescent 
penetrant inspections (FPIs) to detect cracks in the outer diffuser 
case (ODC), removal of any ODC that fails inspection, and updating the 
mandatory inspections in the Airworthiness Limitations Section (ALS) of 
the Instructions for Continued Airworthiness (ICA). Since the FAA 
issued AD 2018-02-10, PW developed a modification to reduce the 
susceptibility of ODC cracking. This AD retains the ALS update 
requirement from AD 2018-02-10, requires replacing certain ODC part 
numbers with parts eligible for installation, expands the applicability 
to all ODC part numbers, and adjusts the compliance threshold of the 
FPIs of the ODC. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective December 26, 2023.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of December 26, 
2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2023-1638; 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 service information identified in this final rule, 
contact Pratt & Whitney Division, 400 Main Street, East Hartford, CT 
06118; phone: (800) 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-2023-1638.

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 2018-02-10, Amendment 39-19163 (FR 83 2896, 
January 22, 2018), (``AD 2018-02-10''). AD 2018-02-10 applied to PW 
Model PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 
engines with ODC part number (P/N) 50J775 or P/N 50J930, installed. The 
NPRM published in the Federal Register on August 8, 2023 (88 FR 53406). 
The NPRM was prompted by an updated analysis by the engine 
manufacturer, which determined that cracks on the ODC originated due to 
high stress in the area between Tt3 boss and thermocouple bracket boss. 
PW developed a modification to improve the surface area between Tt3 
boss and

[[Page 80573]]

thermocouple bracket boss to reduce the ODC's susceptibility to 
cracking.
    Consequently, the FAA determined that it is necessary to expand the 
applicability to all ODC P/Ns, adjust the initial FPI threshold for the 
ODC to improve the inspection program, and to require certain ODCs to 
be replaced with an ODC that has been modified to lower the stresses in 
the area between Tt3 boss and thermocouple bracket boss.
    In the NPRM, the FAA proposed to continue to require retain certain 
requirements of AD 2018-02-10. In the NPRM, the FAA also proposed to 
require revising the ALS of the existing airplane maintenance manual or 
ICA and your existing approved maintenance program, as applicable, to 
include piece-part inspections of the ODC; expanding the applicability 
to include all engines; initial and repetitive FPIs, and depending on 
the results of the FPI, require removal or re-inspection of the ODC. 
Lastly the NPRM proposed to require replacement of certain ODCs with a 
part eligible for installation at next piece-part exposure.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from three commenters. Commenters 
included United Airlines, The Boeing Company, and Air Lines Pilots 
Association, International. All commenters supported 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 manufacturer contact information, this AD is 
adopted as proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed PW Alert Service Bulletin (ASB) PW4G-112-A72-347, 
Revision 4, dated September 1, 2022. This ASB provides guidance on 
performing FPIs on certain bosses of the ODC. 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 PW Service Bulletin (SB) PW4G-112-72-357, dated 
February 25, 2019. This SB provides procedures to modify and re-
identify ODC assemblies to lower the stresses in the area between the 
Tt3 boss and the thermocouple bracket boss.

Costs of Compliance

    The FAA estimates that this AD, affects 108 engines installed on 
airplanes of U.S. registry. The FAA has no way to determine the number 
of operators that will replace the ODC with a modified ODC or a zero-
time ODC. As a result, the total cost on U.S. operators for these 
actions is not estimated.
    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
----------------------------------------------------------------------------------------------------------------
Perform high sensitivity FPI of the     10 work-hours x $85 per               $0            $850         $91,800
 ODC T3 thermocouple probe boss.         hour = $850.
Revise the ALS........................  1 work-hour x $85 per                  0              85           9,180
                                         hour = $85.
Replace the ODC with modified ODC.....  3 work-hours x $85 per            12,000          12,255  ..............
                                         hour = $255.
Replace the ODC with zero-time ODC....  3 work-hours x $85 per         2,300,000       2,300,255  ..............
                                         hour = $255.
----------------------------------------------------------------------------------------------------------------

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 2018-02-10, Amendment 39-19163 (83 
FR 2896, January 22, 2018); and
0
b. Adding the following new airworthiness directive:

2023-22-02 Pratt & Whitney Division: Amendment 39-22586; Docket No. 
FAA-2023-1638; Project Identifier AD-2022-00466-E.

[[Page 80574]]

(a) Effective Date

    This airworthiness directive (AD) is effective December 26, 
2023.

(b) Affected ADs

    This AD replaces AD 2018-02-10, Amendment 39-19163 (83 FR 2896, 
January 22, 2018).

(c) Applicability

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

(d) Subject

    Joint Aircraft System Component (JASC) Code 7240, Turbine Engine 
Combustion Section.

(e) Unsafe Condition

    This AD was prompted by the discovery of multiple cracked outer 
diffuser cases (ODCs). We are issuing this AD to prevent failure of 
the ODC. This condition, if not addressed, could result in failure 
of the ODC, 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) Within the compliance times specified in paragraphs 
(g)(1)(i) though (iii) of this AD, perform an initial high 
sensitivity fluorescent penetrant inspection (FPI) of the ODC T3 
thermocouple probe boss (Tt3 boss) for crack indications in 
accordance with the Accomplishment Instructions, paragraph 1.F. of 
Part A or paragraph 1.B. of Part B, as applicable, of PW Alert 
Service Bulletin PW4G-112-A72-347, Revision 4, dated September 1, 
2022 (ASB PW4G-112-A72-347, Rev 4).
    (i) For an ODC that has accumulated less than 12,000 cycles 
since new (CSN) with no prior high sensitivity FPI of the ODC Tt3 
boss, perform the high sensitivity FPI before accumulating 9,200 CSN 
or within 1,000 flight cycles (FCs), after the effective date of 
this AD, whichever occurs later.
    (ii) For an ODC with unknown CSN or an ODC that has accumulated 
12,000 CSN or more with no prior high sensitivity FPI of the ODC Tt3 
boss, perform the high sensitivity FPI before accumulating 13,000 
CSN or within 1,000 FCs, after February 26, 2018 (the effective date 
of AD 2018-02-10), whichever occurs later.
    (iii) For an ODC that has undergone a high sensitivity FPI of 
the ODC Tt3 boss prior to the effective date of this AD that 
resulted in no crack indication, perform the high sensitivity FPI 
before accumulating 2,000 FCs since performance of the last FPI or 
during the next engine shop visit, whichever occurs first.
    (iv) For an ODC that has undergone a high sensitivity FPI of the 
ODC Tt3 boss prior to the effective date of this AD that resulted in 
an indication of a crack, perform the actions required by paragraphs 
(g)(3)(i) through (iii) of this AD, as applicable.
    (2) Thereafter, repeat the high sensitivity FPI of the ODC Tt3 
boss at each engine shop visit or before exceeding 2,000 FCs from 
the last high sensitivity FPI of the ODC Tt3 boss, whichever occurs 
first, in accordance with the Accomplishment Instructions, 
paragraphs 1.F. of Part A or paragraph 1.B. of Part B, as 
applicable, of ASB PW4G-112-A72-347, Rev 4.
    (3) If, during any inspection required by paragraphs (g)(1) or 
(2) of this AD, there is any crack indication, perform the actions 
specified in paragraphs (g)(3)(i) through (iii) of this AD.
    (i) For engines installed on an aircraft, repeat the high 
sensitivity FPI or remove the ODC from service in accordance with 
the actions and compliance times specified in the Accomplishment 
Instructions, Part A, paragraphs 1.G. and 1.H., of ASB PW4G-112-A72-
347, Rev 4.
    (ii) For engines not installed on an aircraft, repeat the high 
sensitivity FPI or remove the ODC from service in accordance with 
the actions and compliance times specified in the Accomplishment 
Instructions, Part B, paragraphs 1.C. and 1.D., of PW ASB PW4G-112-
A72-347, Rev 4.
    (iii) For engines at an engine shop visit, before further 
flight, remove the ODC from service.
    (4) Within 30 days after the effective date of this AD, revise 
the Airworthiness Limitations Section (ALS) of the existing engine 
maintenance manual or Instructions for Continued Airworthiness and 
the existing approved maintenance program, as applicable, to include 
the piece-part inspections of the ODC as defined in Table 1 to 
paragraph (g)(4) of this AD.

                                  Table 1 to Paragraph (g)(4)--Addition to ALS
----------------------------------------------------------------------------------------------------------------
                                                              Cleaning,
                                                            inspection and        CIR manual
           Description                   Part No.            repair (CIR)         inspection        CIR manual
                                                            manual section
----------------------------------------------------------------------------------------------------------------
Case, Diffuser, Outer...........  All...................           72-41-13  Inspection/Check (I/     P/N 51A750
                                                                              C-02).
----------------------------------------------------------------------------------------------------------------

    (5) For engines with ODC part number (P/N) 50J775 or 50J930 
installed, at the next piece-part exposure after the effective date 
of this AD, replace the ODC with a part eligible for installation.

(h) Definitions

    (1) For the purpose of this AD, an ``engine shop visit'' is any 
time the ``M'' flange is separated.
    (2) For the purpose of this AD, a ``piece-part exposure'' is 
when the ODC is removed from the engine and fully disassembled.
    (3) For the purpose of this AD, a ``part eligible for 
installation'' is an ODC with P/N 50J775-001, 50J775-002, 50J930-
001, or 50J930-002.

(i) 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 AIR-520 Continued 
Operational Safety Branch, send it to the attention of the person 
identified in paragraph (j) of this AD and email 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.

(j) Related Information

    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].

(k) 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-A72-347, 
Revision 4, dated September 1, 2022.
    (ii) [Reserved]
    (3) For service information identified in this AD, contact Pratt 
& Whitney Division, 400 Main Street, East Hartford, CT 06118; phone: 
(800) 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. For information on the availability of this material 
at the FAA, call (781) 238-7759.
    (5) You may view this material at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].


[[Page 80575]]


    Issued on October 25, 2023.
Caitlin Locke,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2023-25524 Filed 11-17-23; 8:45 am]
BILLING CODE 4910-13-P


