DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-1639; Project Identifier MCAI-2023-00109-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), CL-600-2C10 (Regional Jet Series 700, 701 & 702), CL-600-2C11
(Regional Jet Series 550), CL-600-2D15 (Regional Jet Series 705), CL-
600-2D24 (Regional Jet Series 900), and CL-600-2E25 (Regional Jet
Series 1000) airplanes. This proposed AD was prompted by reports of
power control unit (PCU) rod end fractures due to pitting corrosion,
and a determination that new or more restrictive airworthiness
limitations are necessary. This proposed AD would, for certain
airplanes, require revising the existing maintenance or inspection
program, as applicable, to incorporate new or more restrictive
airworthiness limitations. This proposed AD would also require
accomplishing certain aircraft maintenance manual (AMM) tasks and
corrective actions following short-term or long-term storage. 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
11, 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 under
Docket No. FAA-2023-1639; 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 service information identified in this NPRM, contact
MHI RJ Aviation Group, Customer Response Center, 3655 Ave. des Grandes-
Tourelles, Suite 110, Boisbriand, Quebec J7H 0E2 Canada; North
America toll-free telephone 833-990-7272 or direct-dial telephone 450-
990-7272; fax 514-855-8501; email thd.crj@mhirj.com; website mhirj.com.
You may view this service information 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: Gabriel Kim, 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 ADDRESSES. Include ``Docket No. FAA-2023-1639; Project Identifier
MCAI-2023-00109-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
the 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
Gabriel Kim, 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-2023-03, dated January 20, 2023
(Transport Canada AD CF-2023-03) (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), CL-600-2C10 (Regional Jet Series
700, 701 & 702), CL-600-2C11 (Regional Jet Series 550), CL-600-2D15
(Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900), and
CL-600-2E25 (Regional Jet Series 1000) airplanes. The MCAI states that
in-service reports of PCU rod end fractures due to pitting corrosion
led to the issuance of Transport Canada AD CF-2018-29, dated November
2, 2018 (which corresponds to FAA AD 2019-19-08, Amendment 39-19744 (84
FR 60902, November 12, 2019) (AD 2019-19-08). AD 2019-19-08 requires
detailed inspections of the elevator PCU rod ends and applicable
corrective actions, and prohibits using certain aircraft maintenance
manual tasks. Pitting corrosion can cause the PCU end rod spherical
bearing to seize, potentially inducing a bending moment on the PCU
output rod. The bending moment will eventually fracture the rod end.
This condition, if not corrected, could lead to a disconnect between
the PCU and the elevator or rudder control surface, resulting in
potential loss of the control surface function or inadequate flutter
suppression. Since Transport Canada AD CF-2018-29 was issued, MHI RJ
conducted further safety analyses and determined that new or more
restrictive airworthiness limitations are necessary for the operational
check of each individual rudder PCU and elevator PCU. Additionally,
Transport Canada determined that certain return-to-service AMM tasks
are needed following short-term or long-term airplane storage.
The FAA is proposing 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-2023-1639.

Related Service Information Under 1 CFR Part 51

The FAA reviewed MHI RJ Temporary Revisions ALI-0757 and ALI-0759,
both dated September 24, 2021. This service information specifies new
or more restrictive airworthiness limitations for the elevator and
rudder PCUs.
The FAA also reviewed the following service information. This
service information specifies, among other tasks, operational tests of
the rudder control and elevator control systems, and detailed
inspections of the rudder PCU rod end spherical ball and elevator PCU
rod end spherical ball, and corrective actions. Corrective actions
include making sure that the applicable parts are moving or rotating
correctly. These documents are distinct since they apply to different
airplane models in different configurations.
Subject 27-23-01, Power Control Unit (PCU)--Rudder,
Chapter 27--Flight Controls, MHI RJ CRJ700/900/1000 Aircraft
Maintenance Manual, Part 2, CSP B-001, Revision 71, dated December 16,
2022.
Subject 27-33-01, Power Control Unit (PCU)--Elevator,
Chapter 27, Flight Controls, MHI RJ CRJ700/900/1000 Aircraft
Maintenance Manual, Part 2, CSP B-001, Revision 71, dated December 16,
2022.
Task 27-21-00-710-805, Operational Test of the Rudder
Control System, Subject 27-21-00, Rudder Control System, Chapter 27,
Flight Controls, of MHI RJ CRJ200 Aircraft Maintenance Manual, CSP A-
001, Revision 66, dated October 10, 2022.
Task 27-23-01-220-801, Detailed Inspection of the Rudder
PCU Rod End Spherical Ball, Subject 27-23-01, Power Control Unit (PCU),
Rudder, Chapter 27, Flight Controls, of MHI RJ CRJ200 Aircraft
Maintenance Manual, CSP A-001, Revision 66, dated October 10, 2022.
Task 27-31-00-710-803, Operational Test of the Elevator
Control System, Subject 27-31-00, Elevator Control System, Chapter 27,
Flight Controls, of MHI RJ CRJ200 Aircraft Maintenance Manual, CSP A-
001, Revision 66, dated October 10, 2022.
Task 27-33-01-220-801, Detailed Inspection of the Elevator
PCU Rod End Spherical Ball, Subject 27-33-01, Power Control Unit (PCU),
Elevator, Chapter 27, Flight Controls, of MHI RJ CRJ200 Aircraft
Maintenance Manual, CSP A-001, Revision 66, dated October 10, 2022.
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.

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,
the FAA has been notified of the unsafe condition described in the MCAI
and service information referenced above. The FAA is proposing this AD
because the FAA evaluated all the relevant information and determined
the unsafe condition described previously is likely to exist or develop
on other products of the same type design.

Proposed Requirements of This NPRM

This proposed AD would require revising the existing maintenance or
inspection program, as applicable, to
incorporate new or more restrictive airworthiness limitations. This
proposed AD would also require accomplishing certain AMM tasks and
corrective actions following short-term or long-term storage.
This proposed AD would require revisions to certain operator
maintenance documents to include new actions (e.g., inspections).
Compliance with these actions is required by 14 CFR 91.403(c). For
airplanes that have been previously modified, altered, or repaired in
the areas addressed by this proposed AD, the operator may not be able
to accomplish the actions described in the revisions. In this
situation, to comply with 14 CFR 91.403(c), the operator must request
approval for an alternative method of compliance according to paragraph
(j)(1) of this proposed AD.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 1,125 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 determined that revising the 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

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: