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PROPOSED AD BOMBARDIER, INC.: Docket No. FAA-2021-0101; Project Identifier MCAI-2020-01084-T.
(a) COMMENTS DUE DATE

    The FAA  must receive  comments on  this airworthiness  directive (AD)
    action by April 12, 2021.

(b) AFFECTED ADS

    None.

(c) APPLICABILITY

    This  AD applies  to  Bombardier,  Inc., Model  BD-100-1A10 airplanes,
    certificated  in  any  category, serial  numbers  20003  through 20457
    inclusive, and 20501 through 22999 inclusive.

(d) SUBJECT

    Air Transport Association (ATA) of America Code 27, Flight controls.

(e) REASON

    This  AD was  prompted by  a  report  that the  inboard multi-function
    spoiler (MFS) surfaces failed to  deploy, which was caused by  missing
    notches on the piston seal of the MFS power control units (PCUs).  The
    FAA is issuing this AD to address MFS PCUs with improperly  configured
    piston seals,  which could  cause degraded  proportional lift  dumping
    (PLD) function. This condition could hinder the airplane from carrying
    out an emergency descent, resulting in structural damage and injury to
    occupants.

(f) COMPLIANCE

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

(g) DEFINITION OF AFFECTED PART

    For the purpose of this AD, an affected MFS PCU is an MFS PCU that has
    a serial number of 0001  through 1410 inclusive, except for  those MFS
    PCUs having the serial numbers listed in figure 1 to paragraph (g)  of
    this AD and  except for those  with the suffix  "A" at the  end of the
    serial number (i.e., serial number 1025A).
    ______________________________________________________________________
      FIGURE 1 TO PARAGRAPH (G) OF THIS AD: SERIAL NUMBERS THAT ARE NOT   
                                            AFFECTED                      
    ______________________________________________________________________
            66              605             1287            1395
            72              671             1334            1396
            175             720             1337            1397
            200             727             1368            1400
            331             728             1369            1401
            441             773             1370            1403
            448             778             1373            1404
            449             812             1376            1405
            456             831             1380            1406
            470             887             1382            1407
            494             991             1385            1408
            495             1049            1386            1409
            498             1208            1387            -
            499             1236            1388            -
            561             1284            1394            -
    ______________________________________________________________________

(h) REQUIRED ACTIONS

(1) Within 12 months after the effective date of this AD: Do an inspection
    to determine  if affected  MFS PCUs  are installed  on the airplane in
    accordance with Paragraph 2.B.  of Bombardier Service Bulletin  100-27
    -17, Revision 03, dated June 19, 2020; or Bombardier Service  Bulletin
    350-27-010, dated June 19, 2020;  as applicable. A review of  airplane
    maintenance records is  acceptable in lieu  of this inspection  if the
    serial number of the MFS PCU can be conclusively determined from  that
    review.

(2) Within 12 months  after  the  effective  date of this AD:  Replace any
    affected MFS PCUs with MFS  PCUs that are not affected,  in accordance
    with  Paragraphs  2.C.,  2.D.,  2.E.,  and  2.F.,  as  applicable,  of
    Bombardier Service  Bulletin 100-27-17,  Revision 03,  dated June  19,
    2020; or Bombardier Service Bulletin 350-27-010, dated June 19,  2020;
    as applicable.

(i) PARTS INSTALLATION PROHIBITION

    As of the effective date of this AD, no person may install an affected
    MFS PCU, on any airplane.

(j) OTHER FAA 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 certification office,  send
    it to ATTN: Program  Manager, Continuing Operational Safety,  FAA, New
    York ACO Branch, 1600 Stewart  Avenue, Suite 410, Westbury, NY  11590;
    phone:  516-228-7300;  fax: 516-794-5531.  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 Civil Aviation (TCCA); or Bombardier,
    Inc.'s TCCA  Design Approval  Organization (DAO).  If approved  by the
    DAO, the approval must include the DAO-authorized signature.

(k) RELATED INFORMATION

(1) Refer to Mandatory Continuing Airworthiness Information (MCAI) TCCA AD
    CF-2020-26, dated August 4,  2020, for related information.  This MCAI
    may   be   found   in   the    AD   docket   on   the   internet    at
    https://www.regulations.gov by searching  for and locating  Docket No.
    FAA-2021-0101.

(2) For more information about this AD, contact Siddeeq Bacchus, Aerospace
    Engineer, Mechanical Systems and Administrative Services Section, FAA,
    New York  ACO Branch,  1600 Stewart  Avenue, Suite  410, Westbury,  NY
    11590;  phone:  516-228-7362;  fax:  516-794-5531;  email: 9-avs-nyaco
    -cos@faa.gov.

(3) For service information  identified  in this AD,  contact  Bombardier,
    Inc., 200 Cote-Vertu Road West, Dorval, Quebec H4S 2A3, Canada;  North
    America toll-free phone: 1-866-  538-1247 or direct-dial phone:  1-514
    -855-2999;      email:      ac.yul@aero.bombardier.com;      internet:
    http://www.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.

Issued on February 18, 2021.  Lance T. Gant,  Director,  Compliance & Air-
worthiness Division, Aircraft Certification Service.

DATES: The FAA must receive comments on this proposed AD by April 12, 2021
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0101; Project Identifier MCAI-2020-01084-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 BD-100-1A10 airplanes. This
proposed AD was prompted by a report that the inboard multi-function
spoiler (MFS) surfaces failed to deploy, which was caused by missing
notches on the piston seal of the MFS power control units (PCUs). This
proposed AD would require an inspection to determine if affected MFS
PCUs are installed, and replacement of affected MFS PCUs. 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 April 12,
2021.

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 https://www.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.

For service information identified in this NPRM, contact
Bombardier, Inc., 200 Cote-Vertu Road West, Dorval, Quebec
H4S 2A3, Canada; North America toll-free phone: 1-866-538-1247 or
direct-dial phone: 1-514-855-2999; email: ac.yul@aero.bombardier.com;
internet: http://www.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.

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2021-
0101; 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, any comments received, and other information. The street
address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Siddeeq Bacchus, Aerospace Engineer,
Mechanical Systems and Administrative Services Section, FAA, New York
ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone:
516-228-7362; 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-2021-0101; Project Identifier
MCAI-2020-01084-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
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this proposed AD.

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
Siddeeq Bacchus, Aerospace Engineer, Mechanical Systems and
Administrative Services Section, FAA, New York ACO Branch, 1600 Stewart
Avenue, Suite 410, Westbury, NY 11590; phone: 516-228-7362; 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.

Discussion

Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued TCCA AD CF-2020-26, dated August 4,
2020 (referred to after this as the Mandatory Continuing Airworthiness
Information, or the MCAI), to correct an unsafe condition for certain
Bombardier, Inc., Model BD-100-1A10 airplanes. You may examine the MCAI
in the AD docket on the internet at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0101.

This proposed AD was prompted by a report that the inboard MFS
surfaces failed to deploy, which was caused by missing notches on the
piston seal of the MFS PCUs. The FAA is proposing this AD to address
MFS PCUs with improperly configured piston seals, which could cause
degraded proportional lift dumping (PLD) function and could hinder the
airplane from carrying out an emergency descent, resulting in
structural damage and injury to occupants. See the MCAI for additional
background information.

Related Service Information Under 1 CFR Part 51

Bombardier has issued the following service information. This
service information describes procedures for an inspection to determine
if affected MFS PCUs are installed, and replacement of affected MFS
PCUs. These documents are distinct since they apply to different
airplane configurations.

Bombardier Service Bulletin 100-27-17, Revision 03, dated
June 19, 2020.

Bombardier Service Bulletin 350-27-010, dated June 19,
2020.

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 the 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 accomplishing the actions specified
in the service information described previously.

Costs of Compliance

The FAA estimates that this proposed AD affects 630 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
Up to 19 work-hours x $85 per hour = Up to $1,615 Up to $19,600 (up to 4 MFS PCUs per airplane) Up to $21,215 (up to 4 MFS PCUs per airplane) Up to $13,365,450 (up to 4 MFS PCUs per airplane)

According to the manufacturer, some or all of the costs of this
proposed AD may be covered under warranty, thereby reducing the cost
impact on affected individuals. The FAA does not control warranty
coverage for affected individuals. As a result, the FAA has included
all known costs in the cost estimate.

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: