DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0458; Project Identifier MCAI-2024-00116-E;
Amendment 39-22694; AD 2024-04-51]
RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney Canada Corp. Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
Pratt & Whitney Canada Corp. (P&WC) Model PT6A-64, PT6A-66, PT6A-66A,
PT6A-66B, PT6A-66D, PT6A-67, PT6A-67A, PT6A-67AF, PT6A-67AG, PT6A-67B,
PT6A-67D, PT6A-67F, PT6A-67P, PT6A-67R, PT6A-67RM, PT6A-67T, PT6A-68,
PT6A-68D, PT6E-67XP, and PT6E-66XT engines. The FAA previously sent
this AD as an emergency AD to all known U.S. owners and operators of
these engines. This AD was prompted by reports of second-stage power
turbine (PT2) blade failures. This AD requires removal of affected PT2
blades prior to the next flight and prohibits installation of affected
PT2 blades, as specified in a Transport Canada Emergency AD, which is
incorporated by reference. The FAA is issuing this AD to address the
unsafe condition on these products.

DATES: This AD is effective March 28, 2024. Emergency AD 2024-04-51,
issued on February 16, 2024, which contained the requirements of this
amendment, was effective with actual notice.
The Director of the Federal Register approved the incorporation by
reference of a certain publication identified in this AD as of March
28, 2024.
The FAA must receive comments on this AD by April 29, 2024.

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-2024-0458; 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, the mandatory continuing airworthiness
information (MCAI), 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 final rule,
contact Transport Canada, Transport Canada National Aircraft
Certification, 159 Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada;
phone: (888) 663-3639; email: TC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca; website: tc.canada.ca/en/aviation.
You may view this material at the FAA, Airworthiness
Products Section, Operational Safety Branch, 2200 South 216th Street,
Des Moines, WA. 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-
2024-0458.

FOR FURTHER INFORMATION CONTACT: Barbara Caufield, Aviation Safety
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone:
(781) 238-7146; email: barbara.caufield@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written data, views, or arguments
about this final rule. Send your comments to an address listed under
ADDRESSES. Include ``Docket No. FAA-2024-0458; Project Identifier MCAI-
2024-00116-E'' at the beginning of your comments. The most helpful
comments reference a specific portion of the final rule, 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 final rule 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 final rule.

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 AD 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 AD, 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 AD. 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

The FAA issued Emergency AD 2024-04-51, dated February 16, 2024
(the emergency AD), to address an unsafe condition on P&WC Model PT6A-
64, PT6A-66, PT6A-66A, PT6A-66B, PT6A-66D, PT6A-67, PT6A-67A, PT6A-
67AF, PT6A-67AG, PT6A-67B, PT6A-67D, PT6A-67F, PT6A-67P, PT6A-67R,
PT6A-67RM, PT6A-67T, PT6A-68, PT6A-68D, PT6E-67XP, and PT6E-66XT
engines. The FAA sent the emergency AD to all known U.S. owners and
operators of these engines. The emergency AD requires removal of
affected PT2 blades prior to the next flight. The emergency AD also
prohibits installation of affected PT2 blades.
The emergency AD was prompted by Transport Canada Emergency AD CF-
2024-05, dated February 15, 2024 (Transport Canada Emergency AD CF-
2024-05) (referred to after this as the MCAI), issued by Transport
Canada, which is the aviation authority for Canada, to correct an
unsafe condition on P&WC Model PT6A-64, PT6A-66, PT6A-66A, PT6A-66B,
PT6A-66D, PT6A-66T, PT6A-67, PT6A-67A, PT6A-67AF, PT6A-67AG, PT6A-67B,
PT6A-67D, PT6A-67F, PT6A-67P, PT6A-67R, PT6A-67RM, PT6A-67T, PT6A-68,
PT6A-68B, PT6A-68C, PT6A-68D, PT6A-68T, PT6E-67XP, and PT6E-66XT
engines. The MCAI states that there has been a recent in-service report
of a PT2 blade failure on a model PT6A-67 engine and two reports of PT2
blade failures during testing at the manufacturer's facility. The PT2
blade failures were contained. The manufacturer is investigating the
root cause of the PT2 blade failures, but the preliminary investigation
determined that the affected power turbine modules contained PT2 blades
with part number 3056693-01, which were newly manufactured from the
same raw material. In all cases, the PT2 blades had accumulated less
than 25 hours air time since new. Transport Canada Emergency AD CF-
2024-05 specifies removal of the suspect blades prior to the next
flight and prohibits installation of the suspect blades. Transport
Canada Emergency AD CF-2024-05 states that the corrective actions are
interim actions until the root cause investigation is completed. This
condition, if not addressed, could result in engine power loss or
engine in-flight shut down, resulting in consequent emergency landing
or reduced control of the airplane. The FAA is issuing this AD to
address the unsafe condition on these products.
You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2024-0458.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Transport Canada Emergency AD CF-2024-05, which
requires replacing the affected PT2 blades. Transport Canada Emergency
AD CF-2024-05 also prohibits the installation of the affected PT2
blades. 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 ADDRESSES.

FAA's Determination

This product has been approved by the aviation authority of another
country and is 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 and
service information described above. The FAA is issuing this AD after
determining that the unsafe condition described previously is likely to
exist or develop in other products of the same type design.

AD Requirements

This AD requires accomplishing the actions specified in the MCAI,
except as discussed under ``Differences Between this AD and the MCAI.''

Differences Between This AD and the MCAI

The MCAI applies to P&WC Model PT6A-66T, PT6A-68B, PT6A-68C, and
PT6A-68T engines, but this emergency AD does not as these engines are
not U.S. type-certificated.

Interim Action

The FAA considers that this AD is an interim action. The
manufacturer is currently investigating the root cause of the unsafe
condition identified in this AD. If final action is later identified,
the FAA might consider further rulemaking.

Justification for Immediate Adoption and Determination of the Effective
Date

Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5
U.S.C. 551 et seq.) authorizes agencies to dispense with notice and
comment procedures for rules when the agency, for ``good cause,'' finds
that those procedures are ``impracticable, unnecessary, or contrary to
the public interest.'' Under this section, an agency, upon finding good
cause, may issue a final rule without providing notice and seeking
comment prior to issuance.

Further, section 553(d) of the APA authorizes agencies to make rules
effective in less than thirty days, upon a finding of good cause.
An unsafe condition exists that required the immediate adoption of
Emergency AD 2024-04-51, issued on February 16, 2024, to all known U.S.
owners and operators of these engines. The FAA found that the risk to
the flying public justified waiving notice and comment prior to
adoption of this rule because failure of the PT2 blade could result in
engine power loss or engine in-flight shut down, and consequent
emergency landing or reduced control of the airplane. Given the
significance of the risk presented by this unsafe condition, it must be
immediately addressed. Thus, the FAA has determined that the affected
PT2 blades must be removed before further flight. These conditions
still exist, therefore, notice and opportunity for prior public comment
are impracticable and contrary to the public interest pursuant to 5
U.S.C. 553(b)(3)(B).
In addition, the FAA finds that good cause exists pursuant to 5
U.S.C. 553(d) for making this amendment effective in less than 30 days,
for the same reasons the FAA found good cause to forego notice and
comment.

Regulatory Flexibility Act

The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because FAA has determined
that it has good cause to adopt this rule without prior notice and
comment, RFA analysis is not required.

Costs of Compliance

The FAA estimates that this AD affects 75 engines installed on
aircraft of U.S. registry. The FAA does not know how many affected PT2
blades are installed on each engine. This cost estimate therefore
reflects the cost of replacing one affected PT2 blade per engine.
Replacing more than one affected PT2 blade at the same time would not
incur additional labor costs.
The FAA estimates the following costs to comply with this AD:

Estimated Costs

The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, all of the costs of this AD may
be covered under warranty, thereby reducing the cost impact on affected
operators.

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, and
(2) Will not affect intrastate aviation in Alaska.

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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive: