[4910-13-P]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2023-1640; Project Identifier AD-2022-00283-E; Amendment 3922768; AD 2024-12-04]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all Pratt &
Whitney (PW) Model PW2037, PW2037M, and PW2040 engines with a certain highpressure 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 [INSERT DATE 35 DAYS AFTER DATE OF
PUBLICATION IN THE FEDERAL REGISTER].
The Director of the Federal Register approved the incorporation by reference of a
certain publication listed in this AD as of [INSERT DATE 35 DAYS AFTER DATE OF
PUBLICATION IN THE FEDERAL REGISTER].
ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA2023-1640; 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: help24@pw.utc.com; 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) 2387655; email: carol.nguyen@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 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 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.
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) 7252-17 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 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
Action

Labor Cost

Parts Cost
$0

Cost per
product
$680

Cost on U.S.
operators
$289,000

ECI of the HPT
2nd stage turbine
hub assembly
Visual Inspection
of the HPT 2nd
stage blade
assembly
Dimensional
shadowgraph
inspection of HPT
2nd stage blade
assemblies

8 work-hours x
$85 per hour =
$680
8 work-hours x
$85 per hour =
$680

$0

$680

$289,000

8 work-hours x
$85 per hour =
$680

$0

$680

$289,000

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:
On-condition costs
Action
Replace HPT 2nd
stage turbine hub
assembly
Replace HPT 2nd
stage blade assembly

Labor Cost
0 work-hours x
$85 per hour = $0

Parts Cost
$456,000

Cost per product
$456,000

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
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 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 [INSERT DATE 35 DAYS AFTER
DATE OF PUBLICATION IN THE FEDERAL REGISTER].
(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: ANE-ADAMOC@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.
(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) 2387655; 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 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: help24@pw.utc.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 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
fr.inspection@nara.gov.
Issued on June 11, 2024.

Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2024-14936 Filed: 7/8/2024 8:45 am; Publication Date: 7/9/2024]