DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0679; Project Identifier MCAI-2021-01213-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: Supplemental notice of proposed rulemaking (SNPRM).

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SUMMARY: The FAA is revising a notice of proposed rulemaking (NPRM)
that would have applied to all MHI RJ Aviation ULC Model CL-600-2C10
(Regional Jet Series 700, 701 & 702) airplanes, Model CL-600-2C11
(Regional Jet Series 550) airplanes, Model CL-600-2D15 (Regional Jet
Series 705) airplanes, Model CL-600-2D24 (Regional Jet Series 900)
airplanes, and Model CL-600-2E25 (Regional Jet Series 1000) airplanes.
This action revises the NPRM by proposing to require revising the
existing maintenance or inspection program, as applicable, to
incorporate two aircraft maintenance manual (AMM) tasks. The FAA is
proposing this airworthiness directive (AD) to address the unsafe
condition on these products. Since these actions would impose an
additional burden over those in the NPRM, the FAA is requesting
comments on this SNPRM.

DATES: The FAA must receive comments on this SNPRM by February 27,
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-2022-0679; or in person at Docket Operations between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD
docket contains the NPRM, this SNPRM, the mandatory continuing
airworthiness information (MCAI), any comments received, and other
information. The street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Chirayu A. Gupta, Aerospace Engineer,
Airframe and Propulsion Section, FAA, New York ACO Branch, 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-2022-0679; Project Identifier
MCAI-2021-01213-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 SNPRM.

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 SNPRM 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 SNPRM, 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 SNPRM. Submissions
containing CBI should be sent to Chirayu A. Gupta, Aerospace Engineer,
Airframe and Propulsion Section, FAA, New York ACO Branch, 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

The FAA issued an NPRM to amend 14 CFR part 39 by adding an AD that
would apply to all MHI RJ Aviation ULC Model CL-600-2C10 (Regional Jet
Series 700, 701 & 702) airplanes, Model CL-600-2C11 (Regional Jet
Series 550) airplanes, Model CL-600-2D15 (Regional Jet Series 705)
airplanes, Model CL-600-2D24 (Regional Jet Series 900) airplanes, and
Model CL-600-2E25 (Regional Jet Series 1000) airplanes. The NPRM
published in the Federal Register on June 16, 2022 (87 FR 36269). The
NPRM was prompted by AD CF-2021-38, dated November 5, 2021, issued by
Transport Canada, which is the aviation authority for Canada. Transport
Canada issued AD CF-2021-38, dated November 5, 2021, to address an
unsafe condition.
In the NPRM, the FAA proposed to require revising the existing
maintenance or inspection program, as applicable, to incorporate new
and more restrictive airworthiness limitations.
You may examine Transport Canada AD CF-2021-38, dated November 5,
2021, in the AD docket at regulations.gov under Docket No. FAA-2022-
0679.

Actions Since the NPRM Was Issued

Since the FAA issued the NPRM, the FAA determined it was necessary
to require revising the existing maintenance or inspection program, as
applicable, to incorporate two AMM tasks.
In addition, Transport Canada revised AD CF-2021-38, dated November
5, 2021, and issued Transport Canada AD CF-2021-38R1, dated May 25,
2022 (Transport Canada AD CF-2021-38R1) (also referred to as the MCAI),
to correct an unsafe condition for all MHI RJ Aviation ULC Model CL-
600-2C10 (Regional Jet Series 700, 701 & 702) airplanes, Model CL-600-
2C11 (Regional Jet Series 550) airplanes, Model CL-600-2D15 (Regional
Jet Series 705) airplanes, Model CL-600-2D24 (Regional Jet Series 900)
airplanes, and Model CL-600-2E25 (Regional Jet Series 1000) airplanes.
The MCAI states there have been in-service reports of emergency ram air
valve part number GG670-95019-1 stuck in closed or partially open
positions. An investigation revealed that the emergency ram air valve
is failing due to corrosion of multiple sub-components, which causes an
increase in the breakaway torque that cannot be overcome by the valve
actuator. This condition, if not corrected, could result in a complete
loss of outside air supply, leading to an increase in flight deck and
cabin temperatures and a possible increased level of contaminated air
(carbon monoxide, carbon dioxide, or ozone).
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-2022-0679.

Comments

The FAA received comments from the Air Line Pilots Association,
International, who supported the NPRM without change.
The FAA received additional comments from MHI RJ Aviation ULC. The
following presents the comments received on the NPRM and the FAA's
response to each comment.

Request To Revise Model Designations

MHI RJ Aviation ULC requested that paragraph (g)(1) of the proposed
AD be revised to read ``[MHI RJ] CRJ550/700/900/1000 Series Regional
Jet Series'' instead of ``[MHI RJ] CRJ700/900/1000 Series Regional Jet
Series.''
The FAA disagrees. The citations for required documents match the
nomenclature of the cited documents. For the Temporary Revision (TR)
ALI-0744, dated April 27, 2021, the first page of the document only
identifies ``CRJ700/900/1000 Series Regional Jet.'' Therefore, the
correct citation should be ``[MHI RJ] CRJ700/900/1000 Series Regional
Jet Temporary Revision (TR) ALI-0744, dated April 27, 2021.'' However,
that temporary revision is no longer cited in this proposed AD;
therefore, the FAA has not changed this proposed AD in this regard.

Request To Revise Reference to the MCAI

MHI RJ Aviation ULC requested that paragraph (j)(1) of the proposed
AD be revised to refer to ``CF-2021-38R1'' instead of ``CF-2021-38.''
The FAA agrees and has revised paragraph (j)(1) of this proposed AD
(of the SNPRM) accordingly.

Additional Changes Made to This Proposed AD

This proposed AD (of the SNPRM) introduces new candidate
certification maintenance requirement (CCMR) intervals that the FAA
cannot mandate as CCMRs as specified in the temporary revisions cited
in the proposed A. Therefore, the FAA proposes to mandate two AMM tasks
as specified in Figure 1 to paragraph (g)(1) and Figure 2 to paragraph
(g)(2) of the proposed AD (of the SNPRM). In addition, the figures
include the on-condition replacement requirements specified in
Transport Canada AD CF-2021-38R1, which were not included in the
proposed AD (of the NPRM).

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 the State of Design Authority, it
has notified the FAA of the unsafe condition described in the MCAI
referenced above. The FAA is issuing this SNPRM after determining that
the unsafe condition described previously is likely to exist or develop
on other products of the same type design.
Certain changes described above expand the scope of the NPRM. As a
result, it is necessary to reopen the comment period to provide
additional opportunity for the public to comment on this SNPRM.

Proposed AD Requirements in This SNPRM

This proposed AD would require revising the existing maintenance or
inspection program, as applicable, to incorporate two AMM tasks.

Costs of Compliance

The FAA estimates that this proposed AD affects 1,158 airplanes of
U.S. registry. The FAA estimates the following costs to comply with
this proposed AD:
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: