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PROPOSED AD BOMBARDIER, INC.: Docket No. FAA-2023-0025; Project Identifier MCAI-2022-00804-T.
(a) COMMENTS DUE DATE

    The FAA must receive comments on this airworthiness directive (AD)  by
    March 16, 2023.

(b) AFFECTED ADS

    None.

(c) APPLICABILITY

    This AD applies to  Bombardier, Inc., Model CL-600-2B16  (604 Variant)
    airplanes, certificated in any  category, serial numbers 5701  through
    5990  inclusive, and  6050 through  6162 inclusive,  with an  interior
    modified  in  accordance  with  Supplemental  Type  Certificate  (STC)
    ST02355NY.

(d) SUBJECT

    Air Transport Association (ATA) of America Code 35, Oxygen.

(e) UNSAFE CONDITION

    This AD  was prompted  by reports  of oxygen  leaks caused by cracked,
    brittle  or  broken  oxygen hoses  that  were  found during  scheduled
    maintenance tests of  the airplane oxygen  system. The FAA  is issuing
    this AD to address a leak in the oxygen system. The unsafe  condition,
    if  not  addressed,  could  result in  failure  to  provide  oxygen to
    passengers  and  crew  and result  in  an  oxygen enriched  atmosphere
    creating a fire risk on the airplane.

(f) COMPLIANCE

    Comply  with this  AD within  the compliance  times specified,  unless
    already done.

(g) REPLACEMENT

    At the applicable compliance times specified in paragraphs (g)(1)  and
    (2) of this AD: Replace oxygen system hoses having any part number  in
    the  O2C20T1  series,  and, as  applicable,  the  O2C20T14 series,  in
    accordance  with  the Accomplishment  Instructions  of the  applicable
    service information specified in figure 1 to paragraph (g) of this AD.

(1) For airplanes having, as of the effective date of this AD,  6 years or
    less from the completion of the interior modification specified in STC
    ST02355NY: Within 31 months after the effective date of this AD, or no
    later than 12 months after the completion of the interior modification
    specified in STC ST02355NY, whichever occurs first.

(2) For airplanes having, as of the effective date of this AD, more than 6
    years from the  completion of the  interior modification specified  in
    STC T02355NY: Within 7 months after the effective date of this AD.

               FIGURE 1 TO PARAGRAPH (G) – SERVICE INFORMATION            
    ______________________________________________________________________
    BOMBARDIER AIRPLANE MODEL–           BOMBARDIER SERVICE BULLETIN–
    ______________________________________________________________________
    CL-600-2B16 (604 Variant)       605-35-006, Revision 01, dated January
    Challenger 605                  28, 2022

    CL-600-2B16 (604 Variant)       650-35-002, Revision 01, dated January
    Challenger 650                  28, 2022
    ______________________________________________________________________

(h) OPTIONAL MITIGATION FOR CERTAIN AIRPLANES

    For  airplanes  identified  Bombardier  Service  Bulletin  650-35-002,
    Revision 01, dated January 28, 2022, having, as of the effective  date
    of this  AD, less  than 6  years from  the completion  of the interior
    modification specified in STC ST02355NY: In lieu of accomplishing  the
    oxygen system hose replacement required  by paragraph (g) of this  AD,
    comply with all conditions specified in paragraphs (h)(1) through  (3)
    of this AD.

(1) The passenger oxygen system is tested within 6 months after the effec-
    tive date of this AD,  and  thereafter  at intervals  not to exceed 36
    months,  in accordance with the Accomplishment Instructions of Bombar-
    dier Service Bulletin 650-35-002, Revision 01, dated January 28, 2022.

(2) If, during a test specified in paragraph (h)(2) of this AD,  any  leak
    is found on any hose, all oxygen system hoses having a part number  in
    the  O2C20T1  series  must  be  replaced  before  further  flight   in
    accordance with the Accomplishment Instructions of Bombardier  Service
    Bulletin 650-35-002, Revision 01,  dated January 28, 2022.  Doing this
    replacement terminates the tests specified in paragraph (h)(1) of this
    AD.

(3) Except as specified by paragraph (h)(2) of this AD,  all oxygen system
    hoses having  a part  number in  the O2C20T1  series must  be replaced
    within  6  years  from the  completion  of  the interior  modification
    specified  in STC  ST02355NY.  Doing  this replacement  terminates the
    tests specified in paragraph (h)(1) of this AD.

(i) PARTS INSTALLATION PROHIBITION

    As of the effective date of this AD,  no person may install any oxygen
    system hose having a part number in the O2C20T1 and O2C20T14 series on
    any airplane.

(j) CREDIT FOR PREVIOUS ACTIONS

(1) This paragraph provides credit  for actions required  by paragraph (g)
    of this AD,  if those actions were performed before the effective date
    of this AD using Bombardier Service Bulletin 605-35-006,  dated August
    23, 2021;  or Bombardier Service Bulletin 650-35-002, dated August 23,
    2021; as applicable.

(2) This paragraph provides credit for actions  specified in paragraph (h)
    of this AD,  if those actions were performed before the effective date
    of this AD using Bombardier Service Bulletin 650-35-002,  dated August
    23, 2021.

(k) ADDITIONAL AD PROVISIONS

    The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs):  The Manager,  New York ACO
    Branch,  FAA,  has  the authority  to approve  AMOCs for  this AD,  if
    requested using the  procedures found in  14 CFR 39.19.  In accordance
    with 14 CFR  39.19, send your  request to your  principal inspector or
    responsible  Flight  Standards  Office,  as  appropriate.  If  sending
    information directly to the manager  of the New York ACO  Branch, mail
    it to  ATTN: Program  Manager, Continuing  Operational Safety,  at the
    address identified in paragraph (k)(2)  of this AD or email  to: 9-avs
    -nyaco-cos@faa.gov. If mailing information, also submit information by
    email.  Before  using  any  approved  AMOC,  notify  your  appropriate
    principal inspector, or lacking a principal inspector, the manager  of
    the responsible Flight Standards Office.

(2) Contacting the Manufacturer:  For any requirement in this AD to obtain
    instructions   from   a  manufacturer,   the   instructions  must   be
    accomplished using  a method  approved by  the Manager,  New York  ACO
    Branch,  FAA;  or  Transport Canada;  or Bombardier, Inc.'s  Transport
    Canada Design Approval Organization (DAO). If approved by the DAO, the
    approval must include the DAO-authorized signature.

(l) ADDITIONAL INFORMATION

(1) Refer to Transport Canada AD CF-2022-34,  dated June 20, 2022, for re-
    lated information.  This  Transport Canada AD  may be found  in the AD
    docket at regulations.gov under Docket No. FAA-2023-0025.

(2) For more information about this AD,  contact Elizabeth Dowling,  Aero-
    space Engineer,  Mechanical Systems and Administrative  Services  Sec-
    tion, FAA, New York ACO Branch,  1600 Stewart Avenue, Suite 410, West-
    bury, NY 11590; telephone 516-228-7300; fax 516-794-5531; email 9-avs-
    nyaco-cos@faa.gov.

(3) Service information identified in this AD  that is not incorporated by
    reference is available at the addresses specified in paragraphs (m)(3)
    and (4) of this AD.

(m) MATERIAL INCORPORATED BY REFERENCE

(1) The Director of the Federal Register  approved  the  incorporation  by
    reference  (IBR)  of the service information  listed in this paragraph
    under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this service information as applicable  to do the actions
    required by this AD, unless this AD specifies otherwise.

(i) Bombardier Service Bulletin 605-35-006, Revision 01, dated January 28,
    2022.

(ii) Bombardier Service Bulletin 650-35-002 Revision 01, dated January 28,
     2022.

(3) For service information identified in this AD, contact Bombardier Bus-
    iness Aircraft Customer Response Center, 400 Cte-Vertu Road West, Dor-
    val, Qubec H4S 1Y9, Canada; telephone 514-855-2999; email ac.yul@aero.
    bombardier.com; website bombardier.com.

(4) You may view this service information at the FAA,  Airworthiness Prod-
    ucts 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.

(5) You may view  this service information  that is incorporated by refer-
    ence at the National Archives and Records Administration  (NARA).  For
    information on the availability  of this material  at NARA,  email fr.
    inspection@nara.gov,  or go to: www.archives.gov/federal-register/cfr/
    ibr-locations.html.

Issued on January 24, 2023.  Christina Underwood, Acting Director, Compli-
ance & Airworthiness Division, Aircraft Certification Service.

DATES: The FAA must receive comments  on  this  proposed  AD  by March 16,
2023.
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-0025; Project Identifier MCAI-2022-00804-T]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Bombardier, Inc., Model CL-600-2B16 (604 Variant)
airplanes. This proposed AD was prompted by reports of oxygen leaks
caused by cracked, brittle, or broken oxygen hoses that were found
during scheduled maintenance tests of the airplane oxygen system. This
proposed AD would require replacing oxygen system hoses having any part
number in the O2C20T1 and O2C20T14 series. This AD also would prohibit
installation of affected oxygen hoses. 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 March 16,
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-2023-0025; 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
Bombardier Business Aircraft Customer Response
Center, 400 Cte-Vertu Road West, Dorval, Qubec H4S 1Y9,
Canada; telephone 514-855-2999; email ac.yul@aero.bombardier.com;
website bombardier.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: Elizabeth Dowling, Aerospace Engineer,
Mechanical Systems and Administrative Services Section, FAA, New York
ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
telephone 516-228-7300; fax 516-794-5531; 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-2023-0025; Project Identifier
MCAI-2022-00804-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
Elizabeth Dowling, Aerospace Engineer, Mechanical Systems and
Administrative Services Section, FAA, New York ACO Branch, 1600 Stewart
Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7300; fax 516-
794-5531; 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-2022-34, dated June 20, 2022 (Transport
Canada AD CF-2022-34) (also referred to after this as the MCAI), to
correct an unsafe condition on certain Bombardier, Inc., Model CL-600-
2B16 (604 Variant) airplanes. The MCAI states oxygen leaks were caused
by cracked, brittle, or broken oxygen hoses that were found during
scheduled maintenance tests of the airplane oxygen system. A leak in
the oxygen system may result in failure to provide oxygen to passengers
and crew and result in an oxygen-enriched atmosphere creating a fire
risk on the airplane. See the MCAI for additional background
information.
You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2023-0025.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Bombardier Service Bulletin 605-35-006, Revision
01, dated January 28, 2022. This service information specifies
procedures for replacing oxygen system hoses having any part number in
the O2C20T1 and O2C20T14 series.
The FAA also reviewed Bombardier Service Bulletin 650-35-002,
Revision 01, dated January 28, 2022. This service information specifies
procedures for replacing oxygen system hoses having any part number in
the O2C20T1 series. The service information also specifies optional
mitigating actions for certain airplanes (repetitive testing until
affected parts are replaced).
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 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
and service information described above. The FAA is issuing this NPRM
after determining that the unsafe condition described previously is
likely to exist or develop on other products of the same type design.

Proposed AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified
in the service information already described. This proposed AD would
also prohibit installation of affected oxygen hoses.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 42 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:

Estimated Costs for Required Actions

Labor cost
Parts cost
Cost per product
Cost on U.S. operators
3 work-hours x $85 per hour = $255
$100
$355
$14,910

Estimated Costs for Optional Actions

Labor cost
Parts cost
Cost per product
1 work-hour x $85 per hour = $85
$85
$85

The FAA estimates the following costs to do any necessary on-
condition actions that would be required based on the results of any
optional mitigating actions. The FAA has no way of determining the
number of aircraft that might need this on-condition action:

Estimated Costs of On-Condition Actions

Labor cost
Parts cost
Cost per product
3 work-hours x $85 per hour = $255
$100
$355

The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, some or all of the costs of
this proposed 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

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: