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[Federal Register Volume 89, Number 228 (Tuesday, November 26, 2024)]
[Proposed Rules]
[Pages 93225-93228]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-27659]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2539; Project Identifier MCAI-2023-00971-E]
RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney Canada Corp. Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Pratt & Whitney Canada Corp. (P&WC) Model PW535E and 
PW535E1 engines. This proposed AD was prompted by a manufacturer design 
review that indicated certain flange bolts securing the gas generator 
case and turbine support case are susceptible to cracking at their 
current low-cycle fatigue (LCF) life. This proposed AD would require 
repetitive borescope inspections (BSI) of the gas generator case to 
turbine support case retaining bolts for evidence of bolt cracks, bolt 
fracture, missing bolts, or loose bolts and replacement, if necessary, 
as specified in a Transport Canada AD, which is incorporated by 
reference. The FAA is proposing this AD to address the unsafe condition 
on these products.

DATES: The FAA must receive comments on this NPRM by January 10, 2025.

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 under 
Docket No. FAA-2024-2539; 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, the mandatory continuing airworthiness 
information (MCAI), any comments received, and other information. The 
street address for Docket Operations is listed above.

[[Page 93226]]

    Material Incorporated by Reference:
     For Transport Canada material identified in this proposed 
AD, contact Transport Canada, Transport Canada National Aircraft 
Certification, 159 Cleopatra Drive, Nepean, Ontario, K1A 0N5, Canada; 
phone: (888) 663-3639; email: [email protected]; website: tc.canada.ca/en/aviation.
     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.

FOR FURTHER INFORMATION CONTACT: Barbara Caufield, Aviation Safety 
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: 
(781) 238-7146; 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-2024-2539; Project Identifier 
MCAI-2023-00971-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.
    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 
Barbara Caufield, 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

    Transport Canada, which is the aviation authority for Canada, has 
issued Transport Canada AD CF-2023-60, dated August 14, 2023 (Transport 
Canada AD CF-2023-60) (also referred to as the MCAI), to correct an 
unsafe condition for certain P&WC Model PW535E and PW535E1 engines. The 
MCAI states that data from a design review by the manufacturer 
identified insufficient LCF life for flange bolts securing the engine 
gas generator and turbine support case. At certain high-stress 
circumferential locations, LCF cracks could develop on the flange bolt 
and lead to fracture of the bolt. To address this potential unsafe 
condition, the manufacturer published material that provides 
instructions for repetitive BSIs and replacement of the affected parts. 
The FAA is proposing this AD to prevent fracture of the gas generator 
case to turbine support case retaining bolts. The unsafe condition, if 
not addressed, could result in uncontained engine debris, damage to the 
engine, and damage to the airplane.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2024-2539.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed Transport Canada AD CF-2023-60, which identifies 
the affected gas generator case to turbine support case retaining bolts 
and specifies procedures for repetitive BSIs and replacement. 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.

FAA's Determination

    These products have been approved by the aviation authority of 
another country and are approved for operation in the United States. 
Pursuant to the FAA's bilateral agreement with this State of Design 
Authority, it has notified the FAA of the unsafe condition described in 
the MCAI referenced above. The FAA 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.

Proposed AD Requirements in This NPRM

    This proposed AD would require accomplishing the actions specified 
in Transport Canada AD CF-2023-60 described previously, except for any 
differences identified as exceptions in the regulatory text of this 
proposed AD and except as discussed under ``Differences Between this 
Proposed AD and the MCAI.''

Differences Between This Proposed AD and the MCAI

    Where the service information referenced in Transport Canada AD CF-
2023-60 requires reporting certain information to the manufacturer, 
this proposed AD would not require such a submission.

Explanation of Required Compliance Information

    In the FAA's ongoing efforts to improve the efficiency of the AD 
process, the FAA developed a process to use some civil aviation 
authority (CAA) ADs as the primary source of information for compliance 
with requirements for corresponding FAA ADs. The FAA has been 
coordinating this process with manufacturers and CAAs. As a result, the 
FAA proposes to incorporate Transport Canada AD CF-2023-60 by reference 
in the FAA final rule. This proposed AD would, therefore, require 
compliance with Transport Canada AD CF-2023-60 in its entirety through 
that incorporation, except for any differences identified as exceptions 
in the regulatory text of this proposed AD. Material required by 
Transport Canada AD CF-2023-60 for compliance will be available at 
regulations.gov under Docket No. FAA-2024-2539 after the FAA final rule 
is published.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 1,042 engines installed on airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

[[Page 93227]]

                                                 Estimated Costs
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                                                                                     Cost per      Cost on U.S.
               Action                         Labor cost            Parts cost        product        operators
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BSI of gas generator case to         2 work-hours x $85 per hour              $0            $170        $177,140
 turbine support case retaining       = $170.
 bolts.
----------------------------------------------------------------------------------------------------------------

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

                                               On-Condition Costs
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                                                                                                     Cost per
                   Action                                 Labor cost                Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replacement of the gas generator case to     4 work-hours x $85 per hour = $340.          $4,500          $4,840
 turbine support case retaining bolts.
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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:

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 Canada Corp.: Docket No. FAA-2024-2539; Project 
Identifier MCAI-2023-00971-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by January 10, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Pratt & Whitney Canada Corp. (P&WC) Model 
PW535E and P&WC Model PW535E1 engines, as identified in Transport 
Canada Civil Aviation AD CF-2023-60, dated August 14, 2023 
(Transport Canada AD CF-2023-60).

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a manufacturer design review that 
indicated certain flange bolts securing the gas generator case and 
turbine support case have an inadequate low-cycle fatigue life. The 
FAA is issuing this AD to prevent fracture of the gas generator case 
to turbine support case retaining bolts. The unsafe condition, if 
not addressed, could result in uncontained engine debris, 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

    Except as specified in paragraphs (h) and (i) of this AD: 
Perform all required actions within the compliance times specified 
in, and in accordance with, Transport Canada AD CF-2023-60.

(h) Exceptions to Transport Canada AD CF-2023-60

    (1) Where Transport Canada AD CF-2023-60 requires compliance 
from its effective date, this AD requires using the effective date 
of this AD.
    (2) Where paragraph A.1. of Transport Canada AD CF-2023-60 
refers to ``discrepancy,'' this AD defines that as ``evidence of 
bolt cracks, bolt fracture, missing bolts, or loose bolts.''
    (3) Where paragraph A.2. in Transport Canada AD CF-2023-60 
specifies to ``Repeat the above paragraph A.1. inspection and 
rectification requirements of this AD at intervals not to exceed 400 
engine cycles,'' this AD requires replacing that text with ``Repeat 
the above paragraph A.1. inspection and rectification requirements 
of this AD thereafter at intervals not to exceed 400 engine 
cycles.''
    (4) Where paragraph A.1. in Transport Canada AD CF-2023-60 
specifies to ``Inspect the bolts P/N MS9696-08 and P/N MS9489-06 
within 400 cycles from the effective date of this AD,'' this AD 
requires replacing that text with ``Inspect affected bolts having P/
N MS9696-08 and P/N MS9489-06 within 400 engine cycles from the 
effective date of this AD.''
    (5) Where paragraph A.1. in Transport Canada AD CF-2023-60 
specifies to ``rectify any discrepancy in accordance with the

[[Page 93228]]

Accomplishment Instructions of the applicable SB,'' this AD requires 
replacing that text with ``Following inspection, if any bolts are 
determined to be in an unserviceable condition, before further 
flight, replace the affected bolts in accordance with the applicable 
SB.''

(i) No Reporting Requirement

    Although the service information referenced in Transport Canada 
AD CF-2023-60 specifies to submit certain information to the 
manufacturer, this AD does not include that requirement.

(j) Alternative Methods of Compliance (AMOCs)

    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 (k) 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.

(k) Additional Information

    For more information about this AD, contact Barbara Caufield, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: (781) 238-7146; email: [email protected].

(l) 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) Transport Canada AD CF-2023-60, dated August 14, 2023.
    (ii) [Reserved]
    (3) For Transport Canada material identified in this AD, contact 
Transport Canada, Transport Canada National Aircraft Certification, 
159 Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada; phone: (888) 
663-3639; email: [email protected]; website: tc.canada.ca/en/
aviation.
    (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 www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].

    Issued on November 20, 2024.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-27659 Filed 11-25-24; 8:45 am]
BILLING CODE 4910-13-P
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