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PROPOSED AD BOMBARDIER, INC.: Docket No. FAA-2015-8434; Directorate Identifier 2015-NM-082-AD.
(a) COMMENTS DUE DATE

    We must receive comments by August 28, 2017.

(b) AFFECTED ADS

    None.

(c) APPLICABILITY

    This AD applies to the following Bombardier, Inc. Model DHC-8-401  and
    -402 airplanes,  certificated in  any category,  serial numbers (S/Ns)
    4001,  and  4003 through 4527 inclusive,  equipped with  spoiler power
    control unit (PCU) part numbers (P/Ns) 390700-1007 and -1009 and  that
    have  any serial  number identified  in paragraph  (c)(1), (c)(2),  or
    (c)(3) of this AD.

(1) S/Ns 0474 through 1321 inclusive;

(2) S/Ns identified in the Parker Service Bulletin 390700-27-002, Revision
    1, section 4. Appendix, dated April 13, 2016; and

(3) S/Ns 1394 through 1876 inclusive, without suffix "A."

(d) SUBJECT

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

(e) REASON

    This AD was prompted by the discovery of cracking on two test  spoiler
    PCU manifolds during testing by the manufacturer. We are issuing  this
    AD to prevent cracking of the spoiler PCUs that could lead to the loss
    of multiple flight controls and landing gear systems.

(f) COMPLIANCE

    Comply with this AD within the compliance times specified,  unless al-
    ready done.

(g) INSPECTION/REPLACEMENT

    Within 12,000 flight  hours or 72  months after the  effective date of
    this  AD,  whichever occurs  first:  Remove and  replace  the affected
    spoiler PCUs in accordance  with paragraph 3.B. in  the Accomplishment
    Instructions  of  Bombardier Service  Bulletin  84-27-64,  Revision A,
    dated July 26, 2016.

(h) PARTS INSTALLATION PROHIBITION

    After the actions required by paragraph (g) of this AD have been done,
    no person may install,  on any airplane,  a spoiler PCU,  part  number
    390700-1007 and -1009, with:

(1) S/Ns 0474 through 1321 inclusive;

(2) S/Ns identified in the Parker Service Bulletin 390700-27-002, Revision
    1, section 4. Appendix, dated April 13, 2016; and

(3) S/Ns 1394 through 1876 inclusive, without suffix "A."

(i) CREDIT FOR PREVIOUS ACTIONS

    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 84-27-64,  dated July 15,
    2014.

(j) OTHER FAA AD PROVISIONS

    The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs):  The Manager, New York Air-
    craft Certification Office (ACO),  ANE-170, 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 local Flight Standards District Office, as
    appropriate. If sending  information directly to  the ACO, send  it to
    ATTN: Program  Manager, Continuing  Operational Safety,  FAA, New York
    ACO, 1600  Stewart Avenue,  Suite 410,  Westbury, NY  11590; telephone
    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  local  flight  standards   district
    office/certificate holding district  office. The AMOC  approval letter
    must specifically reference this AD.

(2) Contacting the Manufacturer:  For any requirement in this AD to obtain
    corrective  actions   from  a   manufacturer,  the   action  must   be
    accomplished using  a method  approved by  the Manager,  New York ACO,
    ANE-170,  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)
    Canadian  AD  CF-2015-07R2,  dated  December  14,  2016,  for  related
    information. This MCAI may be found  in the AD docket on the  Internet
    at http://www.regulations.gov by searching for and locating Docket No.
    FAA-2015-8434.

(2) For further information about this AD,  contact Cesar Gomez, Aerospace
    Engineer,  Airframe and Mechanical Systems Branch,  ANE-171,  FAA, New
    York Aircraft Certification Office (ACO),  1600 Stewart Avenue,  Suite
    410, Westbury, NY 11590;  telephone 516-228-7318; fax 516-794-5531; e-
    mail: Cesar.Gomez@faa.gov.

(3) For  service information identified  in this AD,  contact  Bombardier,
    Inc.,  Q-Series Technical Help Desk,  123 Garratt Boulevard,  Toronto,
    Ontario M3K 1Y5, Canada;  telephone 416-375-4000; fax 416-375-4539; e-
    mail thd.qseries@aero.bombardier.com;  Internet http://www.bombardier.
    com. You may view this service information at the FAA,  Transport Air-
    plane Directorate, 1601 Lind Avenue SW., Renton, WA.  For  information
    on the availability of this material at the FAA, call 425-227-1221.

Issued in Renton, Washington, on  June 29, 2017. Michael Kaszycki,  Acting
Manager, Transport Airplane Directorate, Aircraft Certification Service.

DATES: The comment period for the NPRM published  in  the Federal Register
on January 13, 2016 (81 FR 1586), is reopened. We must receive comments on
this SNPRM by August 28, 2017.
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-8434; Directorate Identifier 2015-NM-082-AD]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (SNPRM); reopening
of comment period.

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SUMMARY: We are revising an earlier proposal for certain Bombardier,
Inc., Model DHC-8-401 and -402 airplanes. This action revises the
notice of proposed rulemaking (NPRM) by adding certain airplanes to the
applicability and adding specified actions. We are proposing this
airworthiness directive (AD) to address the unsafe condition on these
products. Since these changes increase the scope of the NPRM, we are
reopening the comment period to allow the public the chance to comment
on these proposed changes.

DATES: The comment period for the NPRM published in the Federal
Register on January 13, 2016 (81 FR 1586), is reopened.

We must receive comments on this SNPRM by August 28, 2017.

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 http://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: U.S. Department of Transportation, Docket
Operations, M-30, West Building, Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.

For service information identified in this proposed AD,
contact Bombardier, Inc., Q-Series Technical Help Desk, 123 Garratt
Boulevard, Toronto, Ontario M3K 1Y5, Canada; telephone 416-375-4000;
fax 416-375-4539; email thd.qseries@aero.bombardier.com; Internet
http://www.bombardier.com. You may view this referenced service
information at the FAA, Transport Airplane Directorate, 1601 Lind
Avenue SW., Renton, WA. For information on the availability of this
material at the FAA, call 425-227-1221.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.
gov by searching for and locating Docket No. FAA-2015-8434;
or in person at the Docket Management Facility between 9 a.m. and
5 p.m., Monday through Friday, except Federal holidays. The AD docket
contains this proposed AD, the regulatory evaluation, any comments
received, and other information. The street address for the Docket
Office (telephone: 800-647-5527) is in the ADDRESSES section. Comments
will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Cesar Gomez, Aerospace Engineer,
Airframe and Mechanical Systems Branch, ANE-171, FAA, New York Aircraft
Certification Office (ACO), 1600 Stewart Avenue, Suite 410, Westbury,
NY 11590; telephone 516-228-7318; fax 516-794-5531.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include "Docket No. FAA-2015-8434;
Directorate Identifier 2015-NM-082-AD" at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this proposed AD based on those comments.

We will post all comments we receive, without change, to http://www.
regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.

Discussion

We issued an NPRM to amend 14 CFR part 39 by adding an AD that
would apply to certain Bombardier, Inc. Model DHC-8-401 and -402
airplanes. The NPRM published in the Federal Register on January 13, 2016
(81 FR 1586) ("the NPRM"). The NPRM was prompted by a discovery of crack-
ing on two test spoiler power control units (PCUs) manifolds during test-
ing by the manufacturer. The NPRM proposed to require replacement of
affected spoiler PCUs.

Actions Since the NPRM Was Issued

Since we issued the NPRM, we have determined that certain airplanes
were inadvertently omitted from the applicability of the NPRM; and
additional actions were necessary.

Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian Airworthiness Directive CF-
2015-07R2, dated December 14, 2016 (referred to after this as the
Mandatory Continuing Airworthiness Information, or "the MCAI"), to
correct an unsafe condition for certain Bombardier, Inc. Model DHC-8-
401 and -402 airplanes. The MCAI states:

During endurance and impulse testing of the spoiler PCU, cracks
were discovered on two test spoiler PCU manifolds. Investigation
determined that the crack initiation was due to the heat treat
process. A cracked spoiler PCU manifold could cause the loss of one
of the two hydraulic systems, resulting in the loss of multiple
flight controls and landing gear systems. This condition, if not
corrected, could adversely affect the continued safe operation and
landing of the aeroplane.

This [Canadian] AD mandates the replacement of the affected
spoiler PCUs.

Revision 1 of this [Canadian] AD was issued to extend the
applicability to include additional aeroplane serial numbers and
also modify the Corrective Actions to specifically mandate section
3.B of the [Service Bulletin] SB 84-27-64, Revision A.

Revision 2 of this [Canadian] AD was issued to correct the SB
referenced in the Background section. SB 84-27-64, Revision A should
have been referenced in lieu of SB 84-27-63, Revision A.

You may examine the MCAI in the AD docket on the Internet at http://www.
regulations.gov by searching for and locating Docket No. FAA-2015-8434.

Related Service Information Under 1 CFR Part 51

Bombardier, Inc. has issued Bombardier Service Bulletin 84-27-64,
Revision A, dated July 26, 2016. The service information describes
procedures for replacement of affected spoiler PCU manifolds.

Parker-Hannifin Corporation has issued Parker Service Bulletin
390700-27-002, Revision 1, dated April 13, 2016. This service bulletin
identifies affected spoiler PCUs that need to be returned to Parker
Customer Support for rework.

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.

Comments

We gave the public the opportunity to participate in developing
this proposed AD. We considered the comment received.

Request To Remove Requirement for Job Set-up and Close-out

Horizon Air requested that paragraph (g) of the proposed AD (in the
NPRM) be revised to remove the requirement for job set-up and close-out
in the Accomplishment Instructions of Bombardier Service Bulletin 84-
27-64, dated July 15, 2014. Horizon Air stated that performing the job
set-up and close-out sections specified in Bombardier Service Bulletin
84-27-64, dated July 15, 2014, as a requirement of the AD, restricts an
operator's ability to perform other maintenance in conjunction with
incorporating Bombardier Service Bulletin 84-27-64, dated July 15,
2014.

We agree that job set-up and close-out may be done using approved
procedures other than those provided in the Accomplishment Instructions
of Bombardier Service Bulletin 84-27-64, dated July 15, 2014, or
Revision A, dated July 26, 2016. Therefore, access and close would not
be specifically required by this proposed AD. We have revised paragraph
(g) of this proposed AD (in the SNPRM) to require only the actions
specified in paragraph 3.B. in the Accomplishment Instructions of
Bombardier Service Bulletin 84-27-64, Revision A, dated July 26, 2016.
We find that this change adequately addresses the commenter's request.

FAA's Determination and Requirements of This SNPRM

This product has been approved by the aviation authority of another
country, and is approved for operation in the United States. Pursuant
to our bilateral agreement with the State of Design Authority, we have
been notified of the unsafe condition described in the MCAI and service
information referenced above. We are proposing this AD because we
evaluated all pertinent information and determined an unsafe condition
exists and 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, we have determined that it is necessary to reopen the comment
period to provide additional opportunity for the public to comment on
this SNPRM.

Costs of Compliance


We estimate that this SNPRM affects 82 airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated costs

Action Labor cost Parts cost Cost per product Cost on U.S. operators
Remove and replace affected PCUs 2 work-hours x $85 per hour = $170 per airplane $10,000 per airplane $10,170 per airplane $833,940

The new requirements of this proposed AD add no additional economic
burden.

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.

We are 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 rule-
making action.

Regulatory Findings

We 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. Is not a "significant rule" under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979);

3. Will not affect intrastate aviation in Alaska; and

4. 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 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 (AD):