Rule2026-08106
Airworthiness Directives; Pratt & Whitney Engines
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
April 24, 2026
Effective
May 29, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is adopting a new airworthiness directive (AD) for certain Pratt & Whitney (PW) Model F117-PW-100, PW2037, PW2037D, PW2037M, PW2040, and PW2040D engines. This AD was prompted by an updated analysis of an event involving an International Aero Engines, LLC (IAE LLC) Model PW1127GA-JM engine, which experienced a high- pressure compressor (HPC) 7th-stage integrally bladed rotor (IBR-7) separation that resulted in an engine shutdown and aborted takeoff. This AD requires repetitive angled ultrasonic inspections (AUSIs) of certain high-pressure turbine (HPT) 1st-stage disks and turbine hubs for any crack indications, and if necessary, removal from service and replacement, and removal from service of certain HPT lenticular seal assemblies. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 91 Issue 79 (Friday, April 24, 2026)</title>
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[Federal Register Volume 91, Number 79 (Friday, April 24, 2026)]
[Rules and Regulations]
[Pages 21945-21950]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-08106]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-0918; Project Identifier AD-2024-00526-E;
Amendment 39-23301; AD 2026-07-06]
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
certain Pratt & Whitney (PW) Model F117-PW-100, PW2037, PW2037D,
PW2037M, PW2040, and PW2040D engines. This AD was prompted by an
updated analysis of an event involving an International Aero Engines,
LLC (IAE LLC) Model PW1127GA-JM engine, which experienced a high-
pressure compressor (HPC) 7th-stage integrally bladed rotor (IBR-7)
separation that resulted in an engine shutdown and aborted takeoff.
This AD requires repetitive angled ultrasonic inspections (AUSIs) of
certain high-pressure turbine (HPT) 1st-stage disks and turbine hubs
for any crack indications, and if necessary, removal from service and
replacement, and removal from service of certain HPT lenticular seal
assemblies. The FAA is issuing this AD to address the unsafe condition
on these products.
DATES: This AD is effective May 29, 2026.
The Director of the Federal Register approved the incorporation by
reference (IBR) of certain publications listed in this AD as of May 29,
2026.
ADDRESSES:
AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-0918; 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:
<bullet> For PW material identified in this AD, contact PW, 400
Main Street, East Hartford, CT 06118; phone: (860) 565-0140; email:
<a href="/cdn-cgi/l/email-protection#d6beb3baa6e4e296a6a4b7a2a2a1bebfa2b8b3aff8b5b9bb"><span class="__cf_email__" data-cfemail="1d7578716d2f295d6d6f7c69696a757469737864337e7270">[email protected]</span></a>; website: <a href="http://connect.prattwhitney.com">connect.prattwhitney.com</a>.
<bullet> You may view this material 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
<a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-2025-0918.
FOR FURTHER INFORMATION CONTACT: Molly Sturgis, Aviation Safety
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone:
(562) 627-5373; email: <a href="/cdn-cgi/l/email-protection#7d1012111104531c530e09080f1a140e3d1b1c1c531a120b"><span class="__cf_email__" data-cfemail="c1acaeadadb8efa0efb2b5b4b3a6a8b281a7a0a0efa6aeb7">[email protected]</span></a>.
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 certain PW Model F117-
PW-100, PW2037, PW2037D, PW2037M, PW2040, PW2040D, PW2043, PW2143, and
PW2643 engines. The NPRM was published in the Federal Register on June
2, 2025 (90 FR 23294). The NPRM was prompted by an updated analysis of
an event involving an IAE LLC Model PW1127GA-JM engine, which
experienced an HPC IBR-7 separation that resulted in an engine shutdown
and aborted takeoff. The analysis revealed that the failure was caused
by a nickel powdered metal anomaly and concluded that there is an
increased risk of failure for additional nickel powdered metal parts in
certain nickel powdered metal production campaigns, and these parts are
susceptible to failure much earlier than previously determined. In the
NPRM, the FAA proposed to require repetitive AUSIs of certain HPT 1st-
stage disks and turbine hubs for any crack indications, and if
necessary, removal from service and replacement, and removal from
service of certain HPT lenticular seal assemblies. During the
publication process of this AD, the type certificate data sheet (TCDS)
was revised and PW Model PW2043, PW2143, and PW2643 engines were
removed from the TCDS. Therefore, this final rule does not apply to
those engine models. The FAA is issuing this AD to address the unsafe
condition on these products.
[[Page 21946]]
Discussion of Final Airworthiness Directive
Updated Material
Since the NPRM was published, the manufacturer has published PW
Alert Service Bulletin (ASB) PW2000 A72-779, Revision No. 1, dated
December 17, 2025. This material corrects an incorrect maintenance
manual task reference for disassembly of components and all other
information is the same as the material in the NPRM. The FAA has
revised the final rule to reference PW ASB PW2000 A72-779, Revision No.
1, dated December 17, 2025, as the appropriate source of material for
the AUSIs of the HPT 1st-stage disk.
Comments
The FAA received comments from five commenters. The commenters were
The Boeing Company (Boeing), Delta Air Lines (DAL), FedEx, MTU
Maintenance Hannover GmbH (MTU), and PW. Boeing concurred with the
contents of the NPRM. The following presents the comments received on
the NPRM and the FAA's response to each comment.
Discussion Regarding the Applicability of the NPRM
MTU stated that the applicability of certain cited material in the
proposed AD does not match the applicability in the proposed AD. MTU
indicated that the material applies to PW Model PW2037, PW2037(M), and
PW2040 engines, while the proposed AD applies to several civil PW2000
engine models.
PW pointed out that the proposed AD would apply to PW Model PW2043,
PW2143, and PW2643 engines, none of which are in service. PW indicated
that a request has been submitted to the FAA for withdrawal of these
models from the TCDS; however, the update was not yet published. PW
stated that there are no necessary actions, or operator burden imposed
by including these models in the AD.
The FAA acknowledges the observations from MTU and PW. The FAA is
aware that certain PW Models are included in the applicability of this
AD but are not listed in the material. During the publication process
of this AD, the TCDS has been revised and PW Model PW2043, PW2143, and
PW2643 engines have been removed. Therefore, those same model engines
have been removed from this AD.
Request To Revise the Cost of Compliance
DAL and FedEx requested that the FAA revise the Cost of Compliance
section of the proposed AD to reflect 14 HPT lenticular seal
assemblies. Both commenters indicated that figure 1 to paragraph (g)(4)
of the proposed AD lists 14 seal assemblies by part number and serial
number, but the Estimated Costs table lists only 13 engines that
require replacement. Additionally, DAL stated that the manufacturer has
confirmed that 14 is the correct number of affected seals.
The FAA agrees for the reasons provided and has revised the Cost of
Compliance section of this AD to indicate there are 14 affected HPT
lenticular seal assemblies.
Request for Re-Inspection Procedure Guidance
DAL requested that the FAA revise paragraphs (g) and (h) of the
proposed AD to specifically state whether HPT 1st-stage disks and
turbine hubs are authorized to be re-inspected after initially failing
an angled ultrasonic inspection (AUSI), and if so, whether the parts
may be returned to service upon passing a re-inspection. DAL indicated
that certain parts have failed initial AUSI but then passed re-
inspection, however the parts were tagged as unserviceable. The
commenter asserted that none of the IBR material provides disposition
instructions for parts that pass a re-inspection.
The FAA disagrees with the request. The current revisions of Non-
Destructive Inspection Procedure (NDIP)-1282 and NDIP-1283 contain
procedures for the AUSI inspections and re-inspections, and are second-
tier references in the IBR material that are necessary to complete the
actions specified in this AD. The FAA did not change this AD as a
result of this comment.
Request To Include Engine Manual (EM) Tasks as Material
DAL and MTU requested that the FAA update paragraphs (g)(1) and (2)
of the proposed AD to include certain PW2000 EM tasks as additional
material for compliance for the HPT 1st-stage disk and turbine hub
inspections in addition to the referenced Alert Service Bulletins
(ASBs). DAL stated that the EM provides the same AUSI scan tasks as the
ASBs, and that PW previously incorporated the NDIPs into the EM tasks.
DAL also noted that adding this reference as an option will provide an
acceptable level of safety.
The FAA disagrees with the request. In determining an appropriate
set of required actions for this unsafe condition, the FAA considered
the recommendations of the manufacturer, the urgency associated with
the subject unsafe condition, and the practical aspect of accomplishing
the required actions using the specified material for most affected
operators. However, under the provisions specified in paragraph (j) of
this AD, the FAA will consider requests for alternative methods of
compliance (AMOCs). The FAA did not change this AD as a result of this
comment.
Request To Include Certain Assembly Part Numbers
DAL requested that the FAA include the assembly part numbers of the
HPT 1st-stage disk assembly and turbine hub assembly, and the detail
part numbers of the HPT 1st-stage disks and turbine hubs in paragraphs
(h) and (i) of the proposed AD. DAL stated that the Form 8130s,
received with each of the parts, occasionally list the assembly level
part number instead of the detail part number, and operators sometimes
track the parts at the assembly level. DAL indicated that specifying
both the detail and assembly part numbers would help to reduce
confusion regarding which parts are affected by the NPRM.
The FAA disagrees with the request but agrees that clarification is
necessary. The definitions specified in paragraphs (h)(2)(i) through
(vi), and the prohibitions specified in paragraphs (j)(1) and (2) of
this AD are dependent on the part having passed the AUSI requirements
specified in paragraph (g) of this AD, which apply to the detail part
number only. Additionally, an AUSI will be completed on a detail part
number at new manufacture, but not on an assembly part number. The FAA
did not change this AD as a result of this comment.
Request To Include Threshold Date for Parts Inspected at Manufacture
DAL requested that the FAA update paragraphs (h)(2)(iii) and
(h)(2)(vi) of the proposed AD to provide an FAA Form 8130-3 date after
which all new zero-time HPT 1st-stage disks and turbine hubs can be
considered parts eligible for installation. MTU requested clarification
of how to determine which new manufacture parts have passed an AUSI
during production. PW requested that the FAA remove paragraphs
(h)(2)(iii) and (vi) of the proposed AD and proposed that the FAA allow
all new manufactured parts to be eligible for installation regardless
of confirmation of receiving an AUSI. PW indicated its fleet management
plan does not require confirmation that new affected parts have
received an AUSI during manufacture to be eligible for installation. PW
also stated that all new parts shipped to PW as of March 1, 2025, have
received AUSIs during
[[Page 21947]]
manufacture, and that all commercial inventory available from PW
commercial spares have received an AUSI. DAL indicated that the
manufacturer should have the ability to provide proof that new parts
have passed an AUSI and are eligible for installation, that operators
do not have access to the data, and placing the burden of proof on
operators is tedious and problematic. DAL also stated that if providing
proof is not possible, then the manufacturer should have the ability to
guarantee to the FAA and operators that all newly manufactured parts
with an FAA Form 8130-3 dated after a certain date have passed an AUSI
and are eligible for installation.
The FAA agrees with the requests. Since operators do not have
access to the necessary data to determine whether zero-time components
have passed an AUSI at new part manufacture, the FAA has determined
that the responsible party may determine if the part is eligible for
installation based on the date specified on the FAA Form 8130-3. The
FAA has revised paragraphs (h)(2)(iii) and (h)(2)(vi) of this AD by
removing the words ``that has passed an AUSI at new part production''
and replacing them with ``that has an FAA Form 8130-3 from the original
equipment manufacturer for new production dated March 1, 2025, or
later.''
Request To Remove Certain Definitions
DAL requested that the FAA remove paragraphs (h)(2)(ii) and (v) of
the proposed AD, eliminating the references to NDIP-1282 and NDIP-1283.
DAL stated that those paragraphs do not provide a revision level or
date for the NDIPs which could cause confusion regarding compliance or
whether an AMOC might be required to allow use of future revisions of
the NDIPs. DAL indicated that those paragraphs all appear to have the
same intent; an AUSI performed on parts that are not new production,
with a passing result that is documented.
The FAA disagrees with the request. The NDIPs referenced in
paragraphs (h)(2)(ii) and (v) of this AD are necessary because some
parts may have received an AUSI in compliance with NDIP-1282 or NDIP-
1283 prior to publication of this AD. Additionally, the revision of the
NDIP is not relevant, as all revisions are acceptable to the FAA for
the purposes of this AD. The FAA did not change this AD as a result of
this comment.
Request To Update Definition of ``Piece-Part Exposure''
DAL requested that the FAA revise the definition of ``piece-part
exposure'' in paragraph (h)(1)(i) and (ii) of the proposed AD (for the
HPT 1st-stage disk and turbine hub) to include removal of all parts
from the disk and hub and correspond with certain PW2000 EM disassembly
tasks. DAL pointed out that the disk and hub can be removed from the
engine as specified in the NPRM, with all the blades removed, but for
the associated PW2000 EM disassembly tasks, removing the blades from
the disk or hub is not the final step in the process and some parts
remain installed on the disk or hub. DAL also stated certain workscope
levels provided by the manufacturer to operators could be nullified by
the definition provided in the NPRM.
The FAA agrees with the request for the reasons provided. The FAA
has revised paragraph (h)(1)(i) of this AD to state: ``. . . when the
HPT 1st-stage disk is removed from the engine and all blades, all
retaining plates, and all airseals are removed from the HPT 1st-stage
disk.'' The FAA has revised paragraph (h)(1)(ii) of this AD to state:
``. . . when the turbine hub is removed from the engine and all blades
and all retaining plates are removed from the turbine hub.''
Request To Remove Revision Date From Referenced Service Bulletins
FedEx requested that the FAA revise certain material citations
specified in paragraphs (g)(1) and (2) of the proposed AD to read
``dated May 2, 2024, or later,'' or remove the revision date entirely.
FedEx stated that if the material is revised in the future, an AMOC
would be required for implementation. FedEx also stated that removing
the date would minimize the effect on operator engineering orders and
maintenance, repair, and overhaul (MRO) inspection provider procedures.
The FAA disagrees with the request. To IBR the material specified
in this AD, the citation must refer to a specific document, including
the specific revision date. Additionally, the FAA is unable to cite a
future revision to a document which does not yet exist. The FAA also
notes that, since the NPRM was published, PW has published PW ASB
PW2000 A72-779, Revision No. 1, dated December 17, 2025. The FAA has
revised this AD to reference PW ASB PW2000 A72-779, Revision No. 1,
dated December 17, 2025 as the appropriate source of material for the
AUSIs of the HPT 1st-stage disk. The FAA did not change this AD as a
result of this comment.
Request To Standardize Compliance Documentation
FedEx requested that the FAA revise paragraph (h)(2)(i) of the
proposed AD to state that for all affected parts, used or new
production, compliance must be recorded on the associated FAA Form
8130-3, and delete paragraphs (h)(2)(ii), (h)(2)(iii), (h)(2)(v), and
(h)(2)(vi). FedEx stated that the specific document type associated
with the terms ``certificate of conformance'' and ``passed an AUSI at
new part production'' is not defined in the NPRM, and that during
records verification or audits, the document format or content may be
considered invalid. FedEx indicated that a single compliance standard
would help to clarify the definitions and the installation prohibition
included in paragraphs (i)(1) and (2) of the proposed AD.
The FAA disagrees with the request. The proposed document (FAA Form
8130-3) does not contain the information necessary to show compliance.
The FAA did not change this AD as a result of this comment.
Request To Mandate Airworthiness Limitation Section (ALS) Updates
Instead of Service Material
PW requested that the FAA revise the NPRM to require updating the
ALS instead of the actions specified in the service material. PW stated
that the inspections specified in the service material for the HPT 1st-
stage disks and 2nd-stage hubs have been included in the ALS/Enhanced
Rotor Inspection (ERI) requirements of the EM as of February 2025 and
are now duplicate requirements.
The FAA disagrees with the request. However, the FAA finds that
updating the ALS provides acceptable mitigation of the unsafe
condition. The FAA has added paragraph (i) of this AD to include
optional terminating action for operators that update their ALS to
include the inspections required by paragraphs (g)(1) through (3) of
this AD.
Request To Allow Cycle Limit for a Certain HPT Lenticular Seal Assembly
PW requested that the FAA revise figure 1 to paragraph (g)(4) of
the proposed AD to add a note to serial number DKLBG48292 stating ``or
2,750 cycles since new, whichever occurs first.'' PW stated that it has
previously communicated to an operator a 2,750 cycle since new removal
requirement for this serial number, while all other HPT lenticular seal
assemblies identified in figure 1 to paragraph (g)(4)
[[Page 21948]]
of the proposed AD only require removal at the next piece-part
exposure.
The FAA agrees with the request. The FAA has removed serial number
DKLBG48292 from figure 1 to paragraph (g)(4) of this AD and moved that
serial number to paragraph (g)(5) of this AD, which states ``. . . or
before exceeding 2,750 cycles since new, whichever occurs first. . .''
Request To Include Additional Serial Numbers
PW requested that the FAA add 25 HPT lenticular seal assembly
serial numbers, which are installed on PW Model F117-PW-100 engines, to
figure 1 to paragraph (g)(4) of the proposed AD. PW stated that the
serial numbers were omitted from the NPRM.
The FAA agrees with the request. The FAA has added the missing
serial numbers to figure 1 to paragraph (g)(4) of this AD. However, the
Cost of Compliance section has not changed because the additional HPT
lenticular seal assemblies are installed on F117 engines which are not
installed on U.S. registered airplanes.
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.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed PW ASB PW2000 A72-779, Revision No. 1, dated
December 17, 2025, and PW ASB PWF117 A72-434, dated May 1, 2024, which
specify procedures for repetitive AUSIs of the HPT 1st-stage disk for
crack indications. This material is distinct since each applies to
different engine models.
The FAA also reviewed PW ASB PW2000 A72-780, dated May 2, 2024, and
PW ASB PWF117 A72-433, dated May 1, 2024, which specify procedures for
repetitive AUSIs of the turbine hub. This material is distinct since
each applies to different engine models.
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 the ADDRESSES section.
Costs of Compliance
The FAA estimates that this AD affects 484 engines installed on
airplanes of U.S. registry. The FAA estimates that 14 engines will
require replacement of the HPT lenticular seal assembly. PW Model F117-
PW-100 engines, which are not installed on U.S. registered airplanes,
are not included in this cost estimate.
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
----------------------------------------------------------------------------------------------------------------
AUSI of HPT 1st-stage disk............... 5 work-hours x $85 per hour $0 $425 $205,700
= $425.
AUSI of turbine hub...................... 5 work-hours x $85 per hour 0 425 205,700
= $425.
Replacement of HPT lenticular seal 13 work-hours x $85 per 511,240 512,345 7,172,830
assembly (14 engines). hour = $1,105.
----------------------------------------------------------------------------------------------------------------
The FAA estimates the following costs to do any replacements that
would be required based on the results of the proposed inspections. The
agency has no way of determining the number of engines that might need
these replacements:
On-Condition Costs
------------------------------------------------------------------------
Cost per
Action Labor cost Parts cost product
------------------------------------------------------------------------
Replacement of HPT 1st-stage 10 work-hours x $730,000 $730,850
disk. $85 per hour =
$850.
Replacement of turbine hub... 10 work-hours x 500,000 500,850
$85 per hour =
$850.
------------------------------------------------------------------------
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.
[[Page 21949]]
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:
2026-07-06 Pratt & Whitney: Amendment 39-23301; Docket No. FAA-2025-
0918; Project Identifier AD-2024-00526-E.
(a) Effective Date
This airworthiness directive (AD) is effective May 29, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to Pratt & Whitney (PW) Model F117-PW-100,
PW2037, PW2037D, PW2037M, PW2040, and PW2040D engines.
(d) Subject
Joint Aircraft System Component (JASC) Code 7250, Turbine
Section.
(e) Unsafe Condition
This AD was prompted by an updated analysis of an event
involving an International Aero Engines, LLC Model PW1127GA-JM
engine, which experienced a high-pressure compressor 7th-stage
integrally bladed rotor separation that resulted in an engine
shutdown and aborted takeoff. The FAA is issuing this AD to prevent
failure of the high-pressure turbine (HPT) 1st-stage disk, and
turbine hub. The unsafe condition, if not addressed, could result in
uncontained disk failure, release of high-energy debris, damage to
the engine, damage to the airplane, and possible loss of the
airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
(1) At the next piece-part exposure after the effective date of
this AD and thereafter at every piece-part exposure, do an angled
ultrasonic inspection (AUSI) of the HPT 1st-stage disk for any crack
indications in accordance with Paragraph 4. of the Accomplishment
Instructions of PW Alert Service Bulletin (ASB) PW2000 A72-779,
Revision No. 1, dated December 17, 2025, or Paragraph 4. of the
Accomplishment Instructions of PW ASB PWF117 A72-434, dated May 1,
2024, as applicable to the engine model.
(2) At the next piece-part exposure after the effective date of
this AD and thereafter at every piece-part exposure, do an AUSI of
the turbine hub for any crack indications in accordance with
Paragraph 4. of the Accomplishment Instructions of PW ASB PW2000
A72-780, dated May 2, 2024, or Paragraph 4. of the Accomplishment
Instructions of PW ASB PWF117 A72-433, dated May 1, 2024, as
applicable to the engine model.
(3) If, during any inspection required by paragraph (g)(1) or
(2) of this AD, any crack indication is found, remove the affected
part from service and replace with a part eligible for installation.
(4) For engines with an installed HPT lenticular seal assembly
having a part number (P/N) and serial number (S/N) identified in
figure 1 to paragraph (g)(4) of this AD: At the next piece-part
exposure after the effective date of this AD, remove the HPT
lenticular seal assembly from service and replace with a part
eligible for installation.
Figure 1 to Paragraph (g)(4)--Affected HPT Lenticular Seal Assemblies
------------------------------------------------------------------------
P/N S/N
------------------------------------------------------------------------
1B8575.................................... DKLBG48210
1B8575.................................... DKLBG48244
1B8575.................................... * DKLBGY5898
1B8575.................................... * DKLBGY5907
1B8575.................................... * DKLBGY5908
1B8575.................................... * DKLBGY5911
1B8575.................................... * DKLBGY5913
1B8575.................................... * DKLBGY5915
1B8575.................................... * DKLBGY5916
1B8575.................................... DKLBGY5919
1B8575.................................... * DKLBGY5921
1B8575.................................... DKLBGY5922
1B8575.................................... * DKLBGY5923
1B8575.................................... * DKLBGY5924
1B8575.................................... * DKLBGY5925
1B8575.................................... * DKLBGY5926
1B8575.................................... * DKLBGY5928
1B8575.................................... * DKLBGY5929
1B8575.................................... * DKLBGY5930
1B8575.................................... * DKLBGY5931
1B8575.................................... * DKLBGY5932
1B8575.................................... * DKLBGY5934
1B8575.................................... * DKLBGY5935
1B8575.................................... DKLBGY5936
1B8575.................................... * DKLBGY5937
1B8575.................................... * DKLBGY5938
1B8575.................................... * DKLBGY5939
1B8575.................................... * DKLBGY5940
1B8575.................................... * DKLBGY5941
1B8575.................................... * DKLBGY5943
1B8575.................................... DKLBGY5944
1B8575.................................... DKLBGY5945
1B8575.................................... DKLBGY5946
1B8575.................................... DKLBGY5948
1B8575.................................... DKLBGY5949
1B8575.................................... DKLBGY5952
1B8575.................................... DKLBGY5953
1B8575.................................... DKLBGY5959
------------------------------------------------------------------------
* Serial numbers are PW Model F117-PW-100 engines which are not
installed on U.S. registered airplanes.
(5) For an HPT lenticular seal assembly having P/N 1B8575 and S/
N DKLBG48292: At the next piece-part exposure after the effective
date of this AD or before exceeding 2,750 cycles since new,
whichever occurs first, remove the HPT lenticular seal assembly from
service and replace with a part eligible for installation.
(h) Definitions
(1) For the purpose of this AD, a ``piece-part exposure'' is:
(i) For paragraph (g)(1) of this AD, when the HPT 1st-stage disk
is removed from the engine and all blades, all retaining plates, and
all air seals are removed from the HPT 1st-stage disk.
(ii) For paragraph (g)(2) of this AD, when the turbine hub is
removed from the engine and all blades and all retaining plates are
removed from the turbine hub.
(iii) For paragraph (g)(4) of this AD, when the HPT lenticular
seal assembly is removed from either the HPT 1st-stage disk or the
HPT 2nd-stage hub.
(2) For the purpose of this AD, a ``part eligible for
installation'' is:
(i) An HPT 1st-stage disk having P/N 1B7801, 1B3601, or 1B3601-
001 that has passed the AUSI required by paragraph (g)(1) of this
AD.
(ii) An HPT 1st-stage disk having P/N 1B7801, 1B3601, or 1B3601-
001, that has a certificate of conformance that shows compliance
with Non-Destructive Inspection Procedure (NDIP)-1282.
(iii) A new zero-time HPT 1st-stage disk having P/N 1B7801,
1B3601, or 1B3601-001 that has an FAA Form 8130-3 from the original
equipment manufacturer for new production dated March 1, 2025, or
later.
(iv) A turbine hub having P/N 1B4902, 1B6602, or 1B8002 that has
passed the AUSI required by paragraph (g)(2) of this AD.
(v) A turbine hub having P/N 1B4902, 1B6602, or 1B8002 that has
a certificate of conformance that shows compliance with NDIP-1283.
(vi) A new zero-time turbine hub having P/N 1B4902, 1B6602, or
1B8002 that has an FAA Form 8130-3 from the original equipment
manufacturer for new production dated March 1, 2025, or later.
(vii) Any HPT lenticular seal assembly that does not have a part
number and serial number identified in figure 1 to paragraph (g)(4)
of this AD
(i) Optional Terminating Action
Revising the airworthiness limitations section (ALS) of the
existing engine manual and the operator's existing approved
maintenance program or inspection program, as applicable, by
incorporating the information in figure 2 to paragraph (i) of this
AD, constitutes terminating action for the inspections required by
paragraphs (g)(1) through (3) of this AD.
[[Page 21950]]
Figure 2 to Paragraph (i)--ALS Additional Inspections
----------------------------------------------------------------------------------------------------------------
HPT enhanced
Engine Chapter/ inspection Section Additional inspection
manual section requirements
----------------------------------------------------------------------------------------------------------------
PW2000........................ 1A6231 05-10-00 Table 807........ ........... Revision Date: 2025-02-
01.
HPT 1st-stage 72-52-02 Immersion Ultrasonic
disk. inspect disk. Refer
to 72-52-02,
Inspection/Check-07
(Task 72-52-02-200-
008).
Hub--HPT Stage 2. 72-52-16 Immersion Ultrasonic
inspect hub. Refer to
72-52-16, Inspection/
Check-08 (Task 72-52-
16-200-009).
F117-PW-100................... 1B2412 05-10-00 Table 802........ ........... Revision Date: 2025-02-
01.
HPT 1st-stage 72-52-02 Immersion Ultrasonic
disk. inspect disk. Refer
to 72-52-02,
Inspection/Check-07
(Task 72-52-02-200-
007).
........... ........... Hub--HPT Stage 2. 72-52-16 Immersion Ultrasonic
inspect hub. Refer to
72-52-16, Inspection/
Check-08 (Task 72-52-
16-200-008).
----------------------------------------------------------------------------------------------------------------
(j) Installation Prohibition
(1) As of the effective date of this AD, no person may install
on any engine, an HPT 1st-stage disk having P/N 1B7801, 1B3601, or
1B3601-001, unless it is a part eligible for installation as defined
in paragraph (h)(2) of this AD.
(2) As of the effective date of this AD, no person may install
on any engine, a turbine hub having P/N 1B4902, 1B6602, or 1B8002,
unless it is a part eligible for installation as defined in
paragraph (h)(2) of this AD.
(3) As of the effective date of this AD, no person may install
on any engine, an HPT lenticular seal assembly having a part number
and serial number identified in figure 1 to paragraph (g)(4) of this
AD.
(k) 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 (l) of this AD and email to: <a href="/cdn-cgi/l/email-protection#6f2e22202c2f090e0e41080019"><span class="__cf_email__" data-cfemail="a0e1edefe3e0c6c1c18ec7cfd6">[email protected]</span></a>.
(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.
(l) Additional Information
For more information about this AD, contact Molly Sturgis,
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines,
WA 98198; phone: (562) 627-5373; email: <a href="/cdn-cgi/l/email-protection#107d7f7c7c693e713e63646562777963507671713e777f66"><span class="__cf_email__" data-cfemail="ee8381828297c08fc09d9a9b9c89879dae888f8fc0898198">[email protected]</span></a>.
(m) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference (IBR) of the material listed in this
paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this material as applicable to do the actions
required by this AD, unless the AD specifies otherwise.
(i) Pratt & Whitney (PW) Alert Service Bulletin (ASB) PW2000
A72-779, Revision No. 1, dated December 17, 2025.
(ii) PW ASB PW2000 A72-780, dated May 2, 2024.
(iii) PW ASB PWF117 A72-433, dated May 1, 2024.
(iv) PW ASB PWF117 A72-434, dated May 1, 2024.
(3) For PW material identified in this AD, contact PW, 400 Main
Street, East Hartford, CT 06118; phone: (860) 565-0140; email:
<a href="/cdn-cgi/l/email-protection#3b535e574b090f7b4b495a4f4f4c53524f555e4215585456"><span class="__cf_email__" data-cfemail="6f070a031f5d5b2f1f1d0e1b1b1807061b010a16410c0002">[email protected]</span></a>; website: <a href="http://connect.prattwhitney.com">connect.prattwhitney.com</a>.
(4) You may view this material 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.
(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 <a href="http://www.archives.gov/federal-register/cfr/ibr-locations">www.archives.gov/federal-register/cfr/ibr-locations</a> or email <a href="/cdn-cgi/l/email-protection#3452461a5d5a47445157405d5b5a745a5546551a535b42"><span class="__cf_email__" data-cfemail="1274603c7b7c61627771667b7d7c527c7360733c757d64">[email protected]</span></a>.
Issued on April 10, 2026.
Brian Knaup,
Acting Deputy Director, Integrated Certificate Management
Division,Aircraft Certification Service.
[FR Doc. 2026-08106 Filed 4-23-26; 8:45 am]
BILLING CODE 4910-13-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.