[Federal Register Volume 89, Number 131 (Tuesday, July 9, 2024)]
[Rules and Regulations]
[Pages 56198-56203]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-14936]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-1640; Project Identifier AD-2022-00283-E; 
Amendment 39-22768; AD 2024-12-04]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
Pratt & Whitney (PW) Model PW2037, PW2037M, and PW2040 engines with a 
certain high-pressure turbine (HPT) 2nd stage blade assembly installed. 
This AD was prompted by an in-flight shutdown (IFSD) caused by the 
fracture of HPT 2nd stage turbine hub assembly lugs, which resulted in 
blade liberation and a titanium fire in the high-pressure compressor 
(HPC). This AD requires a visual inspection of the HPT 2nd stage blade 
assemblies for missing contact marks, a dimensional shadowgraph 
inspection of the HPT 2nd stage blade assemblies for blade root profile 
dimensional deviations, and an eddy current inspection (ECI) of the HPT 
2nd stage turbine hub assembly for conforming slot flatness. This AD 
also requires removal from service and replacement of any HPT 2nd stage 
turbine hub assembly or HPT 2nd stage blade assembly that does not pass 
any inspection. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective August 13, 2024.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of August 13, 
2024.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2023-1640; 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, contact Pratt & Whitney, 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, 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-2023-1640.

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 by adding an AD that would apply to all PW Model PW2037, 
PW2037M, and PW2040 engines with a certain HPT 2nd stage blade assembly 
installed. The NPRM published in the Federal Register on August 25, 
2023 (88 FR 58114). The NPRM was prompted by an IFSD caused by the 
fracture of HPT 2nd stage turbine hub assembly lugs, which resulted in 
blade liberation and a titanium fire in the HPC.
    In the NPRM, the FAA proposed to require a visual inspection of the 
HPT 2nd stage blade assemblies for missing contact marks, a dimensional 
shadowgraph inspection of the HPT 2nd stage blade assemblies for blade 
root profile dimensional deviations, and an ECI of the HPT 2nd stage 
turbine hub assembly for conforming slot flatness. The NPRM also 
proposed to require removal from service and replacement of any HPT 2nd 
stage turbine hub assembly or HPT 2nd stage blade assembly that does 
not pass any inspection. The FAA is issuing this AD to address the 
unsafe condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from six commenters. The commenters were 
The Boeing Company (Boeing), Delta Air Lines (Delta), European Air 
Transport (EAT), FedEx Express (FedEx), MTU Maintenance Hannover GmbH 
(MTU), and United Parcel Service (UPS). Boeing supported the NPRM 
without change. The following presents the comments received from 
Delta, EAT, FedEx, MTU, and UPS on the NPRM and the FAA's response to 
each comment.

Request To Exempt Certain Hubs From NPRM Cycle Limit

    Delta requested that the FAA allow hubs with an ECI performed on 
25% of the blade slots to be inspected in accordance with the updated 
dimensional ECI procedure at the next piece part exposure of the HPT 
2nd stage turbine hub assembly, rather than being inspected within the 
cycle limit of the NPRM. Delta noted that Method 2, Step 4 in PW Alert 
Service Bulletin PW2000 A72-777, Initial Issue, dated September 29, 
2021 (PW2000 A72-777, Initial Issue) requires that HPT 2nd stage 
turbine hub assemblies be installed that have passed the HPT 2nd stage 
turbine hub assembly ECI inspection specified in PW2000 Engine Manual, 
Task 72-52-16-200-006, but does not provide guidance on the required 
amount of slots to be inspected. Delta also noted that in the beginning 
of the HPT Field Management Program for this unsafe condition and

[[Page 56199]]

prior to the updated ECI procedure being released for the HPT 2nd stage 
turbine hub assembly, T2 blades were inspected for conformance and 
installed into HPT 2nd stage turbine hub assemblies that were made 
serviceable with previous ECI instructions specified in the PW2000 
Engine Manual, where only 16 out of 64 (25%) slots were required to be 
eddy current inspected.
    The FAA disagrees with the request because there is a higher 
probability of identifying damage to the hub when 100% of the slots are 
inspected. Additionally, allowing hubs that have had an ECI performed 
on 25% of blade slots to wait until the next piece-part exposure for 
the updated ECI would increase the risk of failure. The FAA removed 
previous credit for PW2000 A72-777, Initial Issue, to ensure only HPT 
2nd stage turbine hub assemblies with ECI performed on 100% of the 
blade slots comply with this AD. However, once this AD is published, 
any person may request approval of an alternative method of compliance 
(AMOC) under the provisions of paragraph (i) of this AD. The FAA did 
not change this AD as a result of this comment.

Request To Clarify Applicability for Hubs Divorced From Mating Blades

    Delta requested that the FAA provide guidance on whether hubs that 
were divorced from their mating blades and do not have the required 
inspection results are exempt from the requirements of the NPRM, 
provided that the replacement set of blades to be installed are 
conforming to the visual and shadowgraph inspection requirements of PW 
Alert Service Bulletin PW2000 A72-777, Revision 2, dated April 11, 2023 
(PW2000 A72-777, Rev. 2). Delta stated that there is no way to perform 
the actions required in the NPRM and PW2000 A72-777, Rev. 2 to 
determine serviceability related to this unsafe condition for piece 
part hubs that were already divorced from their mating blades because 
previously installed blades were not traced and may have already gone 
through overhaul process or were scrapped. Delta noted that after 
overhaul or scrapping of blades, visual contact patterns and blade 
profile are no longer available for inspection.
    The FAA agrees that clarification is necessary. Hubs that are 
divorced from their mating blades are not exempt from the requirements 
of this final rule and are considered unserviceable, and therefore no 
exemption is necessary. The FAA did not change this AD as a result of 
this comment.

Request To Define Methodology for Returning Hub to Service

    Delta requested that the FAA define the methodology for returning a 
hub to service using Section 1, Step 1.E. of PW2000 A72-777, Rev. 2, 
and as it relates to previous methods of compliance in previous 
revisions and previous PW Special Instructions (SIs). Delta noted that 
Section 1, Step 1.E. of PW2000 A72-777, Rev. 2 states that if an HPT 
2nd stage blade assembly fails the visual inspection as specified in 
Step 1.B., all related HPT 2nd stage blade assemblies pass the 
shadowgraph inspection as specified in Step 1.C., and the related HPT 
2nd stage hub assembly passes the ECI as specified in Step 1.D, the HPT 
2nd Stage Blade Assemblies could be returned to P&W Customer Technical 
Service for additional inspection to identify the hub serviceability. 
Delta also noted that PW provided Pratt and Whitney Cover E.A. No. 
22FA014, dated 26 October 2022, to accept these hubs into service.
    The FAA disagrees with the request. The FAA notes that while 
Section 1, Step 1.E. of PW2000 A72-777, Rev. 2 is an optional method to 
return the hubs to service, it is not an action required by this AD 
and, therefore, defining the methodology for returning a hub to service 
is unnecessary. The FAA did not change this AD as a result of this 
comment.

Request To Clarify Requirements for Credit for Previous Actions

    Delta requested that the FAA clarify if the required for compliance 
(RC) steps listed in PW2000 A72-777, Rev. 2 carry over to the previous 
versions of the ASB and previous versions of the PW SIs in order to 
provide credit for previous actions. Alternatively, Delta requested 
that the FAA provide the specific steps from each of the previous 
service information documents that are required in order to receive 
credit for previous actions. Delta noted that none of the previous 
revisions of the service information contain RC steps, which could 
cause confusion to operators regarding whether to request an AMOC for 
deviations from those instructions.
    The FAA agrees to revise paragraph (h) of the final rule by 
removing PW2000 A72-777, Initial Issue, and instead including PW SI NO. 
62F-21, dated June 7, 2021, PW SI NO. 62F-21A, dated October 4, 2021, 
PW SI NO. 73F-21, Revision A, dated September 29, 2021 (SI NO. 73F-21, 
Rev. A), and PW SI NO. 73F-21, Initial Issue, dated April 6, 2021 (SI 
NO. 73F-21, Initial Issue).

Request To Add Service Information for Shadowgraph Inspections

    Delta requested that the FAA revise the NPRM to allow the 
shadowgraph inspections of the hub to be performed in accordance with 
all previous revisions to PW SI NO. 78F-21, Revision F, dated June 13, 
2022 (SI NO. 78F-21, Rev. F). Delta noted that PW Alert Service 
Bulletin PW2000 A72-777, Revision 1, dated December 21, 2022 (PW2000 
A72-777, Rev. 1) and PW2000 A72-777, Rev. 2 refer to ``SI 78F-21, Rev F 
released 6/13/2022 or later revision,'' and previous revisions of SI 
NO. 78F-21 are permitted by PW2000 A72-777, Initial Issue. Delta also 
noted that several of the PW SI revisions were issued prior to PW2000 
A72-777, Initial Issue.
    The FAA disagrees with the request to allow the shadowgraph 
inspections of the hub to be performed in accordance with previous 
revisions of SI NO. 78F-21. SI NO. 78F-21, Rev. F already provides 
previous credit for previous revisions, which makes it unnecessary to 
provide credit for actions done using the previous revisions. The FAA 
did not change this AD as a result of this comment.

Request To Add Service Information for Visual Inspections

    Delta requested that the FAA revise the NPRM to allow the visual 
inspections of the hub for contact marks to be performed in accordance 
with SI NO. 73F-21, Initial Issue. Delta noted that PW2000 A72-777, 
Rev. 2 refers to ``SI 73F-21, Rev A released 9/29/2021 or later 
revision,'' and SI NO. 73F-21, Initial Issue is permitted per PW2000 
A72-777. Delta also noted that several of the PW SI revisions were 
issued prior to PW2000 A72-777.
    The FAA agrees with the request and has revised paragraph (h) of 
this AD to include credit for actions done in accordance with SI NO. 
73F-21, Initial Issue.

Request To Clarify Means To Accept New Blades

    Delta requested that the FAA revise the NPRM to clarify that 
communication from PW may be used as a means to accept new blades that 
meet the intent of SI NO. 78F-21, Initial Issue and later revisions. 
Delta noted that they have been using EagleNet Cases from PW for new 
blades where the intent of SI NO. 78F-21, Initial Issue and later 
revisions was accomplished. Delta also noted that PW does not include 
SI NO. 78F-21, Initial Issue or later revisions on the form FAA 8130-3 
for new blades, and the markings on the blades are not always listed.

[[Page 56200]]

    The FAA disagrees with the request. The FAA notes that this AD 
already refers to PW2000 A72-777, Rev. 2, as the appropriate service 
information, which also references SI NO. 78F-21, Rev. F. Additionally, 
SI NO. 78F-21, Rev. F allows credit for communications from PW as a 
means to accept new blades that meet the intent of SI NO. 78F-21, 
Initial Issue and later revisions. The FAA did not change this AD as a 
result of this comment.

Request To Clarify Typographical Error in Service Information

    Delta requested that the FAA comment or provide guidance related to 
on a typographical error contained in the header of pages 3 through 8 
of SI NO. 73F-21, Revision B, dated April 10, 2023 (SI NO. 73F-21, Rev. 
B). The typographical error incorrectly lists the document as Special 
Instruction No. 73F-21 A.
    The FAA acknowledges that there is a typographical error contained 
in the header of pages 3 through 8 of SI NO. 73F-21, Rev. B which 
incorrectly lists the document as Special Instruction No. 73F-21 A. 
However, the typographical error does not change the content of the 
document, which is only allowed as credit for actions accomplished 
prior to the effective date of this AD. Additionally, after the 
effective date of this AD, the appropriate service information for the 
required actions is PW2000 A72-777 R7, Rev. 2. The FAA did not change 
this AD as a result of this comment.

Request To Add Credit Note to AD

    Delta requested that the FAA add the following note from SI NO. 
73F-21, Rev. B to the NPRM; ``Accomplishment of PW2000 Engine Manual 
(Revision 131 or later) 72-52-17 Inspection/Check-14 is equivalent to 
the accomplishment of this Special Instruction 73F-21.'' Delta noted 
that since SI NO. 73F-21, Rev. B includes the PW2000 Engine Manual 
allowance, the same allowance should carry over to previous revisions 
of SI NO. 73F-21 that define the actions to correct the unsafe 
condition.
    The FAA disagrees with the request. Earlier revisions of SI NO. 
73F-21 did not contain this note, and the note specifically applies to 
SI NO. 73F-21, Rev. B. Additionally, after the effective date of this 
AD, the appropriate service information for the required actions is 
PW2000 A72-777 R7, Rev. 2. The FAA did not change this AD as a result 
of this comment.

Request To Clarify the Required Compliance Times

    EAT requested that the FAA update the NPRM to clarify that actions 
identified as ``RC'' in, and in accordance with, the Accomplishment 
Instructions of PW2000 A72-777, Rev. 2, are one-time actions. EAT 
inferred that without this clarification, engines would need to undergo 
the required inspections every 1,800 flight cycles, which would limit 
the on-wing time for all worldwide engines. FedEx requested that the 
FAA revise the NPRM to include a terminating action paragraph. FedEx 
pointed out that neither the NPRM nor the required service information 
explicitly state that the actions are one-time only.
    The FAA agrees to clarify. The actions required by this final rule 
are identified as ``RC'' in PW2000 A72-777, Rev. 2, which is the 
required service information. While not explicitly stated in either 
this final rule or the required service information, those actions are 
one-time only and have no stated repetitive compliance times. The FAA 
also notes that terminating action paragraphs are used specifically to 
terminate repetitive actions. However, the FAA is not mandating 
repetitive actions in this AD and, therefore, a terminating action 
paragraph is unnecessary. The FAA did not change this AD as a result of 
this comment.

Request To Clarify Parts Eligible for Installation

    EAT requested that the FAA clarify that parts that were overhauled 
using the engine manual prior to the availability of PW2000 A72-777 
should be eligible for installation. EAT noted that the NPRM and PW2000 
A72-777, Rev. 2 do not mention HPT 2nd stage turbine hub assemblies 
which were repaired/overhauled before the initial issue of PW2000 A72-
777 in September 2021. EAT also noted that the parts were overhauled in 
accordance with the valid engine manual at that time and therefore 
serviceable and eligible for installation.
    The FAA agrees to clarify. Parts that were overhauled using the 
engine manual prior to the availability of PW2000 A72-777 are not 
eligible for installation. The FAA is publishing this AD to address a 
quality escape on the HPT 2nd stage blade assemblies. Removing the non-
conforming blades and the corresponding HPT 2nd stage turbine hub from 
service is necessary to correct the unsafe condition. If the actions 
performed prior to the effective date of this AD do not meet the 
definition of a part eligible for installation, the part cannot be 
installed on an engine. Additionally, the FAA has included credit for 
previous actions, using certain service information, in paragraph (h) 
of this AD, provided that those actions were done before the effective 
date of this AD. The FAA did not change this AD as a result of this 
comment.

Request To Reduce Inspection Requirements for Certain Hub Assemblies

    EAT requested that the FAA revise the NPRM to allow HPT 2nd stage 
turbine hub assemblies removed prior to the initial issue of PW2000 
A72-777 to pass only the 100% lug ECI inspection, instead of requiring 
all blades previously installed on the hub to pass the visual and 
shadowgraph inspection. EAT pointed out that the requirement for all 
blades to pass the visual and shadowgraph inspections was not a 
mandatory action at that time.
    The FAA disagrees with the request. In order to correct the unsafe 
condition, the HPT 2nd stage blade assemblies with part number (P/N) 
1B7522 must pass the visual and shadowgraph inspections in order to be 
considered a part eligible for installation. Additionally, the 
serviceability of the HPT 2nd stage turbine hub assembly is dependent 
on the blade assemblies passing the visual and shadowgraph inspections. 
If the blade assemblies do not pass those inspections, then the HPT 2nd 
stage turbine hub assembly also does not pass and becomes 
unserviceable. The FAA did not change this AD as a result of this 
comment.

Request To Clarify Guidance on Early Inspections Using Engine Manual

    FedEx requested that the FAA revise paragraph (g) of the proposed 
AD and PW2000 A72-777, Rev. 2, Section 2, Paragraph 1.B. to provide 
guidance for operators that began conducting inspections early in 
collaboration with the engine manufacturer. FedEx noted that the 
general visual inspection requirement for blades installed on engines 
with serial numbers listed in Table 1 on page 9 of PW2000 A72-777, Rev. 
2 is waived by a Note in Section 2, Paragraph 1.B. of PW2000 A72-777, 
Rev. 2. FedEx also noted that some engines were inspected before the 
initial release of PW2000 A72-777, before the release of earlier 
revisions of the SI, or per existing instructions for continued 
airworthiness that were published at the time which makes it impossible 
to directly claim compliance with the actions identified as ``RC'' 
within the Accomplishment Instructions of PW2000 A72-777, Rev. 2. FedEx 
also provided the following example: some

[[Page 56201]]

engines were inspected per PW2000 Engine Manual 72-52-15, Insp/Chk -06 
(Firtree ECI) and 72-52-17, Insp/Chk -14 (blade shadowgraph) in the 
period between February, 2021 and September, 2021 (prior to their 
October 1, 2021 revision date).
    The FAA agrees to provide guidance for operators that performed 
early inspections in collaboration with the engine manufacturer. Credit 
for compliance with the Firtree ECI can only be claimed if 100% of the 
slots were inspected. Credit may not be claimed for the previous ECI of 
the HPT T2 hub slots for the period between February 2021 and September 
2021 because those instructions only required 25% of the slots to be 
inspected, which does not fully mitigate the unsafe condition. The FAA 
notes that the final field management plan to address this unsafe 
condition is described in this AD. The FAA did not change this AD as a 
result of this comment.

Request To Clarify Inspections for Mixed Blade Engines

    MTU requested that the FAA clarify how to address inspections for 
engines that have a mix of affected and unaffected HPT 2nd stage blade 
assemblies installed. MTU notes that PW2000 SB 72-775 allows 
interchangeability of old and new blade assemblies (differentiated by 
P/N). MTU also inferred that the NPRM is not applicable to an engine 
which has installed all 64 HPT 2nd stage blade assemblies having P/N 
1B8722 in post PW2000 SB 72-775 configuration.
    Engines with a mix of affected and unaffected HPT 2nd stage blade 
assemblies installed must perform the required inspections on the 
affected blades having P/N 1B7522 only, and 100% of the HPT T2 hub 
slots. HPT T2 hubs that fail the ECI on any slot must be removed from 
service. P/N 1B8722 blade assemblies are not required to perform the 
inspections required by this AD. If an engine has 64 HPT 2nd stage 
blade assemblies having P/N 1B8722 installed, then this AD is not 
applicable to that engine. The FAA did not change this AD as a result 
of this comment.

Request To Clarify Credit for Inspections Using Initial Release of SI 
NO. 73F-21

    MTU requested that the FAA provide credit for previous actions done 
in accordance with SI NO. 73F-21, Initial Issue, dated April 6, 2021, 
or earlier.
    The FAA agrees with the request and has updated paragraph (h) of 
this AD to provide credit for the required actions done before the 
effective date of this AD using SI NO. 78F-21, dated April 12, 2021. 
However, operators that prefer to address the unsafe condition by means 
other than those specified in the referenced service information may 
request an AMOC in accordance with paragraph (i) of this AD.

Request To Change Compliance Time

    UPS requested that the FAA revise the NPRM to allow a longer 
compliance time. UPS noted that PW part shortages and supply chain 
constraints have resulted in long lead times. UPS also stated that the 
required compliance times are not adequate to maintain PW2000 engine 
spare levels, which would negatively impact UPS operations.
    The FAA disagrees with the request to allow a longer compliance 
time in this AD. In developing an appropriate compliance time, the FAA 
considered the urgency associated with the subject unsafe condition, 
the availability of required parts, and the practical aspect of 
accomplishing the required modification within a period of time that 
corresponds to the normal scheduled maintenance for most affected 
operators. The FAA has determined that the compliance time provides an 
acceptable level of safety. However, under the provisions of paragraph 
(i) of this AD, the FAA will consider requests for an extension of the 
compliance time if sufficient data are submitted to substantiate that 
the change would provide an acceptable level of safety. The FAA did not 
change this AD as a result of this comment.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes, and 
any other changes described previously, this AD is adopted as proposed 
in the NPRM. None of the changes will increase the economic burden on 
any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed PW2000 A72-777, Rev. 2, which specifies procedures 
for performing a visual inspection of the HPT 2nd stage blade 
assemblies for missing contact marks, dimensional shadowgraph 
inspection of the HPT 2nd stage blade assemblies for dimensional 
deviations, and an ECI of the HPT 2nd stage turbine hub assembly for 
conforming slot flatness. This service information also specifies 
removal from service of any HPT 2nd stage turbine hub assembly or HPT 
2nd stage blade assembly that does not pass any inspection. 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 425 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
----------------------------------------------------------------------------------------------------------------
ECI of the HPT 2nd stage turbine hub    8 work-hours x $85 per                $0            $680        $289,000
 assembly.                               hour = $680.
Visual Inspection of the HPT 2nd stage  8 work-hours x $85 per                 0             680         289,000
 blade assembly.                         hour = $680.
Dimensional shadowgraph inspection of   8 work-hours x $85 per                 0             680         289,000
 HPT 2nd stage blade assemblies.         hour = $680.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
inspections. The agency has no way of determining the number of 
aircraft that might need these replacements:

[[Page 56202]]



                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace HPT 2nd stage turbine hub assembly....  0 work-hours x $85 per hour = $0        $456,000        $456,000
Replace HPT 2nd stage blade assembly..........  0 work-hours x $85 per hour = $0          17,000          17,000
----------------------------------------------------------------------------------------------------------------

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

    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 adding the following new airworthiness 
directive:

2024-12-04 Pratt & Whitney: Amendment 39-22768; Docket No. FAA-2023-
1640; Project Identifier AD-2022-00283-E.

(a) Effective Date

    This airworthiness directive (AD) is effective August 13, 2024.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Pratt & Whitney (PW) Model PW2037, PW2037M, 
and PW2040 engines with a high-pressure turbine (HPT) 2nd stage 
blade assembly, part number (P/N) 1B7522 installed.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine 
Section.

(e) Unsafe Condition

    This AD was prompted by an in-flight shutdown caused by the 
fracture of HPT 2nd stage turbine hub assembly lugs. The FAA is 
issuing this AD to prevent failure of the HPT 2nd stage turbine hub 
assembly lug and HPT 2nd stage blade assemblies. The unsafe 
condition, if not addressed, could result in the uncontained release 
of the HPT 2nd stage blade assemblies, 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

    Before exceeding the applicable compliance times specified in 
Planning Information, Compliance, page 2, of PW Alert Service 
Bulletin PW2000 A72-777, Revision 2, dated April 11, 2023 (PW2000 
A72-777, Rev. 2), or before accumulating 500 cycles after the 
effective date of this AD, whichever occurs later, perform all 
applicable actions identified as ``RC'' (required for compliance) 
in, and in accordance with, the Accomplishment Instructions of 
PW2000 A72-777, Rev. 2.

(h) Credit for Previous Actions

    You may take credit for the inspections required by paragraph 
(g) of this AD if you performed those inspections before the 
effective date of this AD using PW Alert Service Bulletin PW2000 
A72-777, Revision 1, dated December 21, 2022, PW Special Instruction 
(SI) NO. 62F-21, Initial Issue, dated June 7, 2021, or PW SI NO. 
62F-21A, dated October 4, 2021.
    You may take credit for the inspection specified in Section 1, 
paragraph 1.B. of the Accomplishment Instructions of PW2000 A72-777, 
Rev. 2, which is required by paragraph (g) of this AD, if you 
performed the inspection before the effective date of this AD using 
PW SI NO. 73F-21, Initial Issue, dated April 6, 2021, or PW SI NO. 
73F-21, Revision A, dated September 29, 2021.

(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, 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.
    (3) For service information that contains steps that are labeled 
as Required for Compliance (RC), the following provisions apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. An AMOC is required for any deviations to RC steps, 
including substeps and identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(j) Additional 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].

[[Page 56203]]

(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 PW2000 A72-777, 
Revision 2, dated April 11, 2023.
    (ii) [Reserved]
    (3) For Pratt & Whitney service information, contact Pratt & 
Whitney, 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 01803. For information on the availability of this 
material at the FAA, call (817) 222-5110.
    (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].

    Issued on June 11, 2024.
Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-14936 Filed 7-8-24; 8:45 am]
BILLING CODE 4910-13-P