DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0219; Project Identifier MCAI-2023-00764-T;
Amendment 39-22755; AD 2024-10-09]
RIN 2120-AA64

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

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 MHI RJ Aviation ULC Model CL-600-2B19 (Regional Jet Series 100
& 440) airplanes. This AD was prompted by a determination that a more
restrictive airworthiness limitation is necessary. This AD requires
revising the existing maintenance or inspection program, as applicable,
to incorporate a more restrictive airworthiness limitation, as
specified in a Transport Canada 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 July 19, 2024.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of July 19,
2024.

ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2024-0219; 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
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:
For material, 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; 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 206-231-3195. It is also available in the AD docket at
regulations.gov under Docket No. FAA-2024-0219.

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

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 MHI RJ Aviation
ULC Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. The
NPRM published in the Federal Register on February 2, 2024 (89 FR
7299). The NPRM was prompted by AD CF-2023-41, dated June 15, 2023,
issued by Transport Canada, which is the aviation authority for Canada
(Transport Canada AD CF-2023-41) (also referred to as the MCAI). The
MCAI states that a more restrictive airworthiness limitation has been
developed due to reports of an unclear effectivity for airworthiness
limitation (AWL) task number 53-41-180 in the Maintenance Requirements
Manual (MRM), Part 2. If the revised task, AWL number 53-41-180, is not
performed at the required intervals, failures of the strap modification
to the fuselage station (FS) 409 + 128 bulkhead could remain undetected
and could result in the loss of the structural integrity of the
airplane.
In the NPRM, the FAA proposed to require revising the existing
maintenance or inspection program, as applicable, to incorporate a more
restrictive airworthiness limitation, as specified in Transport Canada
AD CF-2023-41. 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-2024-0219.

Discussion of Final Airworthiness Directive

Comments

The FAA received comments from one commenter, Air Wisconsin
Airlines. The following presents the comments received on the NPRM and
the FAA's response to each comment.

Request for Change to Applicability

Air Wisconsin Airlines noted that the proposed applicability in
paragraph (c) of the proposed AD, which references the applicability in
Transport Canada AD CF-2023-41, does not list the applicable reference
serial numbers 7946 through 8113. The commenter requested that the
proposed AD be revised to list the applicable serial numbers, if they
are the same as those listed in Transport Canada AD CF-2023-41.
The FAA disagrees with correcting the applicability of this AD.
Paragraph (c) of this AD states that the AD affects the airplanes
identified in Transport Canada AD CF-2023-41, which has the
applicability as affecting airplanes with serial numbers 7946 through
8113. No changes have been made to this AD regarding this issue.

Request for Clarification of the Applicability of a Task

Air Wisconsin Airlines requested clarification of whether paragraph
(h)(2) of the proposed AD would require revising the maintenance or
inspection program to incorporate a revised task for all airplanes or
only certain airplanes.
The FAA agrees to clarify. Revising the maintenance or inspection
program to incorporate a revised AWL task affects all airplanes
identified in the applicability in paragraph (c) of the AD. A task
within an AWL might have an effectivity for specific airplanes. No
changes have been made to this AD regarding this issue.

Request for Clarification of the Fuselage Station of the Strap
Modification

Air Wisconsin Airlines requested that paragraph (e) of the proposed
AD regarding the location of the strap modification be changed from ``(FS)
409 and 128'' to ``(FS) 409 + 128''. MHI RJ TR 2B-2283 lists the
aircraft station as ``fuselage (FS) 409 + 128 bulkhead.'' In the NPRM,
the location is listed as ``(FS) 409 and 128 bulkhead,'' which sounds
like 2 different locations.
The FAA agrees with the commenter. The FAA has confirmed with the
manufacturer that the location of the strap modification is FS 409 +
128. The FAA has changed this final rule to reflect the proper
location.

Conclusion

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 reviewed the relevant data, considered the
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 this product. 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.

Related Service Information Under 1 CFR Part 51

Transport Canada AD CF-2023-41 specifies procedures for a more
restrictive airworthiness limitation for AWL task number 53-41-180.
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 78 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:
The FAA has determined that revising the existing maintenance or
inspection program takes an average of 90 work-hours per operator,
although the agency recognizes that this number may vary from operator
to operator. Since operators incorporate maintenance or inspection
program changes for their affected fleet(s), the FAA has determined
that a per-operator estimate is more accurate than a per-airplane
estimate. Therefore, the agency estimates the average total cost per
operator to be $7,650 (90 work-hours x $85 per work-hour).

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.

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: