80572 Federal Register / Vol. 88, No. 222 / Monday, November 20, 2023 / Rules and Regulations 

(4) This AD does not adopt the provisions 

specified in paragraphs (4) and (5) of EASA 

AD 2023–0060. 

(5) This AD does not adopt the ‘‘Remarks’’ 

section of EASA AD 2023–0060. 

(l) New Provisions for Alternative Actions 

and Intervals 

After the existing maintenance or 

inspection program has been revised as 

required by paragraph (j) of this AD, no 

alternative actions (e.g., inspections) and 

intervals are allowed unless they are 

approved as specified in the provisions of the 

‘‘Ref. Publications’’ section of EASA AD 

2023–0060. 

(m) Additional AD Provisions 

The following provisions also apply to this 

AD: 

(1) Alternative Methods of Compliance 

(AMOCs): The Manager, International 

Validation 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 

responsible Flight Standards Office, as 

appropriate. If sending information directly 

to the International Validation Branch, send 

it to the attention of the person identified in 

paragraph (n) of this AD. Information may be 

emailed to: 9-AVS-AIR-730-AMOC@faa.gov. 

Before using any approved AMOC, notify 

your appropriate principal inspector, or 

lacking a principal inspector, the manager of 

the responsible Flight Standards Office. 

(2) Contacting the Manufacturer: For any 

requirement in this AD to obtain instructions 

from a manufacturer, the instructions must 

be accomplished using a method approved 

by the Manager, International Validation 

Branch, FAA; or EASA; or Dassault 

Aviation’s EASA Design Organization 

Approval (DOA). If approved by the DOA, 

the approval must include the DOAauthorized signature. 

(n) Additional Information 

For more information about this AD, 

contact Tom Rodriguez, Aviation Safety 

Engineer, FAA, 2200 South 216th St., Des 

Moines, WA 98198; telephone: 206–231– 

3226; email: tom.rodriguez@faa.gov. 

(o) 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 this AD specifies otherwise. 

(3) The following service information was 

approved for IBR on December 26, 2023. 

(i) European Union Aviation Safety Agency 

(EASA) AD 2023–0060, dated March 16, 

2023. 

(ii) [Reserved] 

(4) The following service information was 

approved for IBR on December 23, 2020 (85 

FR 73404, November 18, 2020). 

(i) European Union Aviation Safety Agency 

(EASA) AD 2019–0141, dated June 17, 2019. 

(ii) [Reserved] 

(5) For EASA ADs 2023–0060 and 2019– 

0141, contact EASA, Konrad-Adenauer-Ufer 

3, 50668 Cologne, Germany; telephone +49 

221 8999 000; email ADs@easa.europa.eu; 

website easa.europa.eu. You may find these 

EASA ADs on the EASA website at 

ad.easa.europa.eu. 

(6) You may view this service information 

at the FAA, Airworthiness Products Section, 

Operational Safety Branch, 2200 South 216th 

St., Des Moines, WA. For information on the 

availability of this material at the FAA, call 

206–231–3195. 

(7) 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 fr.inspection@nara.gov. 

Issued on October 27, 2023. 

Caitlin Locke, Director, 

Compliance & Airworthiness Division, 

Aircraft Certification Service. 

[FR Doc. 2023–25496 Filed 11–17–23; 8:45 am] 

BILLING CODE 4910–13–P 

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. 

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: help24@prattwhitney.com; 

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: carol.nguyen@faa.gov. 

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 


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Federal Register / Vol. 88, No. 222 / Monday, November 20, 2023 / Rules and Regulations 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 reinspection 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

Action Labor cost Parts cost Cost per 

product 

Cost on U.S. 

operators 

Perform high sensitivity FPI of the ODC T3 

thermocouple probe boss.

10 work-hours × $85 per hour = $850 ........... $0 $850 $91,800 

Revise the ALS ............................................... 1 work-hour × $85 per hour = $85 ................. 0 85 9,180 

Replace the ODC with modified ODC ............ 3 work-hours × $85 per hour = $255 ............. 12,000 12,255 ........................

Replace the ODC with zero-time ODC ........... 3 work-hours × $85 per hour = $255 ............. 2,300,000 2,300,255 ........................

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 

■ 1. The authority citation for part 39 

continues to read as follows: 

Authority: 49 U.S.C. 106(g), 40113, 44701. 

§ 39.13 [Amended] 

■ 2. The FAA amends § 39.13 by: 

■ a. Removing Airworthiness Directive 

2018–02–10, Amendment 39–19163 (83 

FR 2896, January 22, 2018); and 

■ 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. 


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80574 Federal Register / Vol. 88, No. 222 / Monday, November 20, 2023 / Rules and Regulations 

(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 

Description Part No. 

Cleaning, 

inspection 

and repair (CIR) 

manual section 

CIR manual inspection CIR manual 

Case, Diffuser, Outer ................................... All ................... 72–41–13 Inspection/Check (I/C–02) .......................... P/N 51A750 

(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 ‘‘piecepart 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: ANEAD-AMOC@faa.gov. 

(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: carol.nguyen@faa.gov. 

(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: help24@

prattwhitney.com; 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 fr.inspection@nara.gov. 


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Federal Register / Vol. 88, No. 222 / Monday, November 20, 2023 / Rules and Regulations 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 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2023–1637; Project 

Identifier MCAI–2023–00184–E; Amendment 

39–22588; AD 2023–22–04] 

RIN 2120–AA64 

Airworthiness Directives; Rolls-Royce 

Deutschland Ltd & Co KG Engines 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: The FAA is adopting a new 

airworthiness directive (AD) for all 

Rolls-Royce Deutschland Ltd & Co KG 

(RRD) Model Trent 1000–A2, Trent 

1000–AE2, Trent 1000–C2, Trent 1000– 

CE2, Trent 1000–D2, Trent 1000–E2, 

Trent 1000–G2, Trent 1000–H2, Trent 

1000–J2, Trent 1000–K2, and Trent 

1000–L2 engines. This AD was 

prompted by reports of cracking and 

separation of certain low-pressure 

turbine (LPT) stage 1 blade assemblies. 

This AD requires initial and repetitive 

inspections of affected LPT stage 1 blade 

assemblies for cracking or separation 

and, depending on the results of the 

inspections, reduction of the inspection 

interval or replacement of the LPT stage 

1 blade set and disk, as specified in a 

European Union Aviation Safety Agency 

(EASA) AD, which is incorporated by 

reference. 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–2023–1637; 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, the mandatory 

continuing airworthiness information 

(MCAI), 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 EASA, KonradAdenauer-Ufer 3, 50668 Cologne, 

Germany; phone: +49 221 8999 000; 

email: ADs@easa.europa.eu; website: 

easa.europa.eu. You may find this 

material on the EASA website at 

ad.easa.europa.eu. 

• 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–2023–1637. 

FOR FURTHER INFORMATION CONTACT: 

Sungmo Cho, Aviation Safety Engineer, 

FAA, 2200 South 216th Street, Des 

Moines, WA 98198; phone: (781) 238– 

7241; email: sungmo.d.cho@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Background 

The FAA issued a notice of proposed 

rulemaking (NPRM) to amend 14 CFR 

part 39 by adding an AD that would 

apply to all RRD Model Trent 1000–A2, 

Trent 1000–AE2, Trent 1000–C2, Trent 

1000–CE2, Trent 1000–D2, Trent 1000– 

E2, Trent 1000–G2, Trent 1000–H2, 

Trent 1000–J2, Trent 1000–K2, and 

Trent 1000–L2 engines. The NPRM 

published in the Federal Register on 

July 31, 2023 (88 FR 49361). The NPRM 

was prompted by EASA AD 2023–0027, 

dated January 31, 2023 (EASA AD 

2023–0027) (also referred to as the 

MCAI) issued by EASA, which is the 

Technical Agent for the Member States 

of the European Union. The MCAI states 

that manufacturer inspections detected 

cracking and separation of blade pairs in 

the weld region of certain LPT stage 1 

blade assemblies. A blade assembly 

consists of a pair of blades welded 

together at the outer shroud. There are 

85 LPT stage 1 blade assemblies in one 

set. Such cracking and separation could 

cause failure of affected parts and 

damage to the LPT module. 

You may examine the MCAI in the 

AD docket at regulations.gov under 

Docket No. FAA–2023–1637. 

In the NPRM, the FAA proposed to 

require initial and repetitive inspections 

of affected LPT stage 1 blade assemblies 

for cracking or separation and, 

depending on the results of the 

inspections, reduction of the inspection 

interval or replacement of the LPT stage 

1 blade set and disk. The FAA is issuing 

this AD to address the unsafe condition 

on these products. 

Discussion of Final Airworthiness 

Directive 

Comments 

The FAA received one comment from 

The Boeing Company (Boeing). Boeing 

supported the NPRM without change. 

Conclusion 

These products have been approved 

by the aviation authority of another 

country and are approved for operation 

in the United States. Pursuant to the 

FAA’s bilateral agreement with this 

State of Design Authority, it has notified 

the FAA of the unsafe condition 

described in the MCAI referenced 

above. 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. Except for minor editorial 

changes, this AD is adopted as proposed 

in the NPRM. 

Related Service Information Under 1 

CFR Part 51 

The FAA reviewed EASA AD 2023– 

0027, which specifies procedures for 

inspection of affected LPT stage 1 blade 

assemblies and replacement of the LPT 

stage 1 blade set and disk. EASA AD 

2023–0027 also specifies a reduction of 

the repetitive inspection intervals if 

cracking or separation is detected and 

meets certain criteria. 

This material 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 26 engines installed on airplanes 

of U.S. registry. 

The FAA estimates the following 

costs to comply with this AD: 


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