[Federal Register Volume 88, Number 164 (Friday, August 25, 2023)]
[Proposed Rules]
[Pages 58114-58116]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-18259]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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 

  Federal Register / Vol. 88, No. 164 / Friday, August 25, 2023 / 
Proposed Rules  

[[Page 58114]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-1640; Project Identifier AD-2022-00283-E]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt 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 proposed 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 proposed AD would 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 inspection, and an eddy 
current inspection (ECI) of the HPT 2nd stage turbine hub assembly for 
conforming slot flatness. This proposed AD would also require removal 
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 
proposing this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by September 
25, 2023.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to regulations.gov. Follow 
the instructions for submitting comments.
     Fax: (202) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    AD Docket: You may examine the AD docket at regulations.gov by 
searching for and locating 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 NPRM, any comments 
received, and other information. The street address for Docket 
Operations is listed above.
    Material Incorporated by Reference:
     For service information identified in this NPRM, contact 
Pratt & Whitney, 400 Main Street, East Hartford, CT 06118; phone: (800) 
565-0140; email: [email protected]; website: connect.prattwhitney.com.
     You may view this service information at the FAA, 
Airworthiness Products Section, 1200 District Avenue, Burlington, MA 
01803. For information on the availability of this material at the FAA, 
call (817) 222-5110.

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:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2023-1640; Project Identifier 
AD-2022-00283-E'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. The FAA 
will consider all comments received by the closing date and may amend 
this proposal because of those comments.
    The FAA has been informed that PW has done some outreach with 
affected operators regarding the proposed corrective actions for this 
unsafe condition. As a result, affected operators are already aware of 
the proposed corrective actions and, in some cases, have already begun 
planning for replacement of certain HPT 2nd stage turbine hub 
assemblies and HPT 2nd stage blade assemblies. Therefore, the FAA has 
determined that a 30-day comment period is appropriate given the 
particular circumstances related to the proposed correction of this 
unsafe condition.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
regulations.gov, including any personal information you provide. The 
agency will also post a report summarizing each substantive verbal 
contact received about this NPRM.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this NPRM, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and they will not be placed in the public 
docket of this NPRM. Submissions containing CBI should be sent to Carol 
Nguyen, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des 
Moines, WA 98198. Any commentary that the FAA receives which is not 
specifically designated as CBI will be placed in the public docket for 
this rulemaking.

Background

    The FAA received a report of an IFSD of a Model PW2037 engine 
installed on a Boeing Model 757 airplane that occurred on September 8, 
2020. Subsequent investigation by the manufacturer found that two 
turbine hub assembly lug fractures on the HPT 2nd stage turbine hub 
assembly caused

[[Page 58115]]

the release of four HPT 2nd stage blade assemblies part number (P/N) 
1B7522, which caused damage upstream in the HPC, resulting in a 
titanium fire. Further investigation by the manufacturer revealed the 
blade root profile of certain HPT 2nd stage blade assemblies did not 
conform to the manufacturer's type design. The non-conforming blades 
installed in the HPT 2nd stage turbine hub assembly caused uneven 
contact on the HPT 2nd stage turbine hub assembly lug leading to 
increased attachment stress resulting in failure of the HPT 2nd stage 
turbine hub assembly lug and HPT 2nd stage turbine hub assembly. This 
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.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed PW Turbojet Engine Service Bulletin PW2000 A72-
777, Revision 2, dated April 11, 2023 (PW2000 A72-777 Rev. 2). This 
service information specifies procedures for performing a visual 
inspection of the HPT 2nd stage blade assemblies, dimensional 
shadowgraph inspection of the HPT 2nd stage blade assemblies, and an 
ECI of the HPT 2nd stage turbine hub assembly. 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.

Proposed AD Requirements in This NPRM

    This proposed AD would require accomplishing the actions identified 
as ``RC'' (required for compliance) in the Accomplishment Instructions 
of PW2000 A72-777 Rev. 2, except for any differences identified as 
exceptions in the regulatory text of this proposed AD.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 425 engines installed on airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
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 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 
proposed inspections. The agency has no way of determining the number 
of aircraft that might need these replacements:

                                               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

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Would not affect intrastate aviation in Alaska, and
    (3) Would 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 Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

[[Page 58116]]

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:

Pratt & Whitney: Docket No. FAA-2023-1640; Project Identifier AD-
2022-00283-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by September 25, 2023.

(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 Turbojet Engine 
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 actions required by paragraph (g) of 
this AD if you performed these actions before the effective date of 
this AD in accordance with PW Turbojet Engine Service Bulletin 
PW2000 A72-777, Initial Issue, dated September 29, 2021, or PW 
Turbojet Engine Service Bulletin PW2000 A72-777, Revision 1, dated 
December 21, 2022.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, AIR-520 Continued Operational Safety Branch, 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19. In accordance with 14 
CFR 39.19, send your request to your principal inspector or local 
Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the certification office, 
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) Except as required by paragraph (g) of this AD: 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) Related Information

    For more information about this AD, contact Carol Nguyen, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: (781) 238-7655; email: [email protected].

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Pratt & Whitney Turbojet Engine Service Bulletin PW2000 A72-
777, Revision 2, dated April 11, 2023.
    (ii) [Reserved]
    (3) For service information identified in this AD, 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 service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on July 24, 2023.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-18259 Filed 8-24-23; 8:45 am]
BILLING CODE 4910-13-P