DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2012; Project Identifier MCAI-2023-01208-T]
RIN 2120-AA64

Airworthiness Directives; MHI RJ Aviation ULC (Type Certificate
Previously Held by Bombardier, Inc.) Airplanes

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 all MHI RJ Aviation ULC Model CL-600-2B19 (Regional Jet Series 100
& 440) airplanes. This proposed AD was prompted by the discovery of ten
ultrasonic inspections associated with airworthiness limitations (AWL)
tasks and structural deviation inspection requirements (SDIR) tasks
potentially not detecting cracks. This proposed AD would require
repetitive ultrasonic inspections of certain structural areas for
cracking as specified in a Transport Canada AD, which is proposed for
incorporation by reference (IBR), and repair of cracking, as
applicable. This proposed AD would also prohibit use of the previous
revisions of certain procedures and mandate the use of the revised
procedures when performing the inspections required by the associated
AWL and SDIR tasks. 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
23, 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-2024-2012; 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.
Material Incorporated by Reference:
For Transport Canada material in this proposed AD, contact
Transport Canada, Transport Canada National Aircraft Certification, 159
Cleopatra Drive, Nepean, Ontario K1A 0N5, Canada; telephone 888-663-
3639; email TC.AirworthinessDirectives-Consignesdenavigabilite.TC@tc.gc.ca.
You may find this material on the
Transport Canada website at tc.canada.ca/en/aviation. It is also
available at regulations.gov under Docket No. FAA-2024-2012.
You may view this material at the FAA, Airworthiness
Products Section, Operational Safety Branch, 2200 South 216th St., Des
Moines, WA. For information on the availability of this material at the
FAA, call 206-231-3195.

FOR FURTHER INFORMATION CONTACT: Yaser Osman, Aviation Safety Engineer,
FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone
(516) 228-7300; email: 9-avs-nyaco-cos@faa.gov.

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 the ADDRESSES section. Include ``Docket No. FAA-2024-2012;
Project Identifier MCAI-2023-01208-T'' 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 Yaser Osman, Aviation
Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY
11590; telephone (516) 228-7300; email 9-avs-nyaco-cos@faa.gov. 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-2023-74, dated November 21, 2023
(Transport Canada AD CF-2023-74) (also referred to as the MCAI), to
correct an unsafe condition for all MHI RJ Aviation ULC Model CL-600-
2B19 (Regional Jet Series 100 & 440) airplanes. The MCAI states MHI RJ
Aviation ULC discovered ten ultrasound (i.e., ultrasonic) inspection
procedures in Part 4 of the non-destructive testing manual (NDTM),
which is associated with AWL tasks and SDIR tasks, could potentially
not detect cracks. The MCAI stated this is due to differences in sound
attenuation between airplane structures assembled with faying surface
sealant and the calibration reference standards used to calibrate the
ultrasonic testing probes which were assembled without faying surface
sealant.
The FAA is proposing this AD to address undetected cracks in
certain structural areas. The unsafe condition, if not addressed, could
result in structural failure of the airplane. You may examine the MCAI
in the AD docket at regulations.gov under Docket No. FAA-2024-2012.

Material Incorporated by Reference Under 1 CFR Part 51

Transport Canada AD CF-2023-74 specifies procedures for repetitive
ultrasonic inspections of certain structural areas for cracking. The
structural areas include, but are not limited to, certain lateral beam
web and lower cap flanges, engine support beam cap angles, engine
support beams, webs, and doublers. Transport Canada AD CF-2023-74 also
prohibits the use of the previous revisions of certain ultrasonic
inspection procedures specified in Part 4 of the NDTM and mandates the
use of revised procedures when performing the inspections required by
the associated AWL and SDIR tasks.
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

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
referenced above. The FAA is issuing this NPRM after determining that
the unsafe condition described previously is likely to exist or develop
in 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-2023-74 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
NPRM and the MCAI.''

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-2023-74 by reference
in the FAA final rule. This proposed AD would, therefore, require
compliance with Transport Canada AD CF-2023-74 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-2023-74 for compliance will be available at
regulations.gov under Docket No. FAA-2024-2012 after the FAA final rule
is published.

Differences Between This NPRM and the MCAI

Transport Canada AD CF-2023-74 requires repetitive inspections for
cracking but does not specify accomplishing a corrective action if any
cracking is found. Therefore, this proposed AD would require repairing
any cracking found using a method approved by the Manager,
International Validation Branch, FAA; or Transport Canada; or MHI RJ
Aviation ULC's Transport Canada Design Organization Approval (DOA). If
approved by the DOA, the approval must include the DOA-authorized
signature.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 395 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:

Estimated Costs for Required Actions

The FAA has received no definitive data on which to base the cost
estimates for the repairs specified in this proposed AD.

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

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: