(a) EFFECTIVE DATE

    This AD is effective January 9, 2020.

(b) AFFECTED ADS

    This AD replaces AD 2009-09-02, Amendment 39-15888 (74 FR 18121, April
    21, 2009) ("AD 2009-09-02").

(c) APPLICABILITY

    This  AD  applies  to  De Havilland  Aircraft of Canada Limited  (Type
    Certificate Previously Held by Bombardier, Inc.) Model DHC-8-400, -401
    and -402 airplanes, certificated in any category, serial numbers 4001,
    4003, and subsequent,  equipped  with  main landing gear (MLG) forward
    stabilizer brace part number (P/N) 46401-7.

(d) SUBJECT

    Air Transport Association (ATA) of America Code 32, Main landing gear.

(e) REASON

    This AD was prompted  by reports of failures  of the aft hinge  of the
    MLG forward stabilizer brace due to fatigue cracks. The FAA is issuing
    this AD to address failure of the stabilizer brace, which could result
    in the collapse of the MLG.

(f) COMPLIANCE

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

(g) RETAINED INSPECTION AND CORRECTIVE ACTIONS WITH REVISED SERVICE INFOR-
    MATION AND REMOVED REPORTING REQUIREMENT

    This paragraph restates  the requirements of paragraph (f) of AD 2009-
    09-02, with new service information and removed reporting requirement.
    Unless already done, do the following actions:

(1) At  the  applicable  time  specified  in  one  of paragraphs (g)(1)(i)
    through  (iv)  of  this AD:  Perform  non-destructive  inspections for
    damage of the MLG forward stabilizer brace assemblies P/N 46401-7,  in
    accordance with Bombardier Repair  Drawing 8/4-32-099, Issue 1,  dated
    March  10,  2009,  and  Goodrich  Service  Concession  Request 026-09,
    Revision B, dated March 10, 2009; or Bombardier Repair Drawing  8/4-32
    -099, Issue  4, dated  September 4,  2018, and  UTC Aerospace  Systems
    Service Concession Request 026-09, Revision H, dated August 29,  2018.
    Repeat  the inspection  thereafter at  intervals not  to exceed  2,000
    flight cycles.  As of  the effective  date of  this AD, use Bombardier
    Repair Drawing 8/4-32-099, Issue 4,  dated September 4, 2018, and  UTC
    Aerospace Systems Service Concession Request 026-09, Revision H, dated
    August 29, 2018, for the actions required by this paragraph.

(i) For airplanes with MLG forward stabilizer braces that have accumulated
    12,000  or  more  total flight cycles as of May 6, 2009 (the effective
    date of AD 2009-09-02):  Inspect within 50 flight cycles  after May 6,
    2009.

(ii) For  airplanes  with MLG forward stabilizer braces  that have accumu-
     lated 9,000  or more total flight cycles  but fewer than 12,000 total
     flight cycles as of May 6, 2009 (the effective date of AD 2009-09-02)
     Inspect before the accumulation  of  12,050  total flight cycles,  or
     within 500 flight cycles after May 6, 2009, whichever occurs earlier.

(iii) For airplanes  with MLG forward stabilizer braces  that have accumu-
      lated 4,500  or more total flight cycles  but fewer than 9,000 total
      flight cycles  as of May 6, 2009  (the effective date of AD 2009-09-
      02):  Inspect before  the accumulation of 9,500 total flight cycles,
      or  within 1,500 flight cycles after May 6, 2009,  whichever  occurs
      earlier.

(iv) For  airplanes  with MLG forward stabilizer braces  that have accumu-
     lated fewer than 4,500 total flight cycles  as  of  May 6, 2009  (the
     effective date of AD 2009-09-02):  Inspect before the accumulation of
     6,000 total flight cycles.

(2) If any damage is found during any inspection required by paragraph (g)
    (1) of this AD,  before  further flight,  do all applicable corrective
    actions in accordance with Goodrich Service Concession Request 026-09,
    Revision B,  dated  March 10, 2009;  or  UTC Aerospace Systems Service
    Concession Request 026-09,  Revision H,  dated August 29, 2018; except
    as  provided  by  paragraphs (g)(3) through (6) of this AD.  As of the
    effective date of this AD use UTC Aerospace Systems Service Concession
    Request 026-09, Revision H, dated August 29, 2018, for the actions re-
    quired by this paragraph.

(3) For airplanes on which step 24. of Goodrich Service Concession Request
    026-09, Revision B, dated March 10, 2009, has been done:  Within 1,200
    flight cycles after May 6, 2009 (the effective date of AD 2009-09-02),
    rework the MLG forward stabilizer brace,  and  except for airplanes on
    which the rework has been done,  within 600 flight cycles after May 6,
    2009,  do a detailed visual inspection  for  damage  of the stabilizer
    brace apex lugs in accordance with Goodrich Service Concession Request
    026-09,  Revision B,  dated March 10, 2009;  or  UTC Aerospace Systems
    Service Concession Request 026-09,  Revision H, dated August 29, 2018.
    If any damage is found,  repair  before  further flight  in accordance
    with Section C of Goodrich Service Concession Request 026-09, Revision
    B, dated March 10, 2009; or Section C of UTC Aerospace Systems Service
    Concession Request 026-09 Revision H, dated August 29, 2018. As of the
    effective date of this AD use UTC Aerospace Systems Service Concession
    Request 026-09, Revision H, dated August 29, 2018, for the actions re-
    quired by this paragraph.

(4) At  the  applicable  time  specified  in  one of paragraphs  (g)(4)(i)
    through (iii)  of  this  AD,  replace  the  forward  stabilizer  brace
    assembly,  in accordance with Goodrich Service Concession Request 026-
    09, Revision B, dated March 10, 2009; or UTC Aerospace Systems Service
    Concession Request 026-09 Revision H, dated August 29, 2018. As of the
    effective date of this AD,  use  UTC Aerospace Systems Service Conces-
    sion Request 026-09 Revision H, dated August 29, 2018, for the actions
    required by this paragraph.

(i) For airplanes  on which cracking is found during  any  inspection  re-
    quired by this AD,  and  the  cracking exceeds  the limit specified in
    paragraph (g)(4)(i)(A) or (B) of this AD, as applicable:  Replace  the
    assembly before further flight.

(A) For cracking  found  before the effective date of this AD:  The  limit
    specified in Section C  of Goodrich Service Concession Request 026-09,
    Revision B, dated March 10, 2009.

(B) For cracking  found on  or  after  the effective date of this AD:  The
    limit specified  in  Section C  or  Section D of UTC Aerospace Systems
    Service Concession Request 026-09, Revision H, dated August 29, 2018.

(ii) For airplanes on which any cracking is found  after the rework speci-
     fied  in  Section C  of  Goodrich  Service Concession Request 026-09,
     Revision B, dated March 10, 2009 or specified in Section C or Section
     D of UTC Aerospace Systems Service Concession Request 026-09 Revision
     H, dated August 29, 2018: Replace the assembly before further flight.

(iii) For airplanes on which no cracking is found  after the rework speci-
      fied  in  Section C  of  Goodrich Service Concession Request 026-09,
      Revision B,  dated  March 10, 2009;  or  specified  in  Section C or
      Section D of UTC Aerospace Systems Service Concession Request 026-09
      Revision H, dated August 29, 2018: Replace the assembly within 2,700
      flight cycles after doing the rework.

(5) If foreign object damage is found during  any  inspection  required by
    this  AD,  or if damage is found  to a forward stabilizer brace lug or
    stop bracket retention hole apex bushing,  before further flight,  re-
    pair 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); or De Havilland Aircraft of Canada
    Limited's TCCA DAO.  If approved by the DAO, the approval must include
    the DAO-authorized signature.

(6) If any crack is found during the visual inspection  under 10X magnifi-
    cation,  repair  before  further  flight,  in accordance with Goodrich
    Service Concession Request 026-09,  Revision B,  dated March 10, 2009;
    or UTC Aerospace Systems Service Concession Request 026-09, Revision H
    dated August 29, 2018.  As of the effective date of this AD,  use  UTC
    Aerospace Systems Service Concession Request 026-09, Revision H, dated
    August 29, 2018, for the actions required by this paragraph.

(7) Before the accumulation of 6,000 total  flight cycles  on the MLG for-
    ward stabilizer braces, or within  600 flight hours after May  6, 2009
    (the effective date  of AD 2009-09-02),  whichever occurs later:  Do a
    detailed visual inspection for cracking of both MLG forward stabilizer
    braces  and  do  all  applicable  liquid  penetrant  inspections   for
    cracking, in accordance with Bombardier Q400 All Operator Message 338,
    dated February 23, 2009. Repeat the inspection thereafter at intervals
    not to exceed 600  flight hours. If any  cracking is found during  any
    inspection required by this paragraph, repair before further flight in
    accordance with Bombardier Repair  Drawing 8/4-32-099, Issue 1,  dated
    March  10,  2009,  and  Goodrich  Service  Concession  Request 026-09,
    Revision B, dated March 10, 2009; or Bombardier Repair Drawing  8/4-32
    -099, Issue  4, dated  September 4,  2018, and  UTC Aerospace  Systems
    Service Concession Request 026-09, Revision H, dated August 29,  2018.
    As of  the effective  date of  this AD,  use Bombardier Repair Drawing
    8/4-32-099,  Issue  4,  dated September  4,  2018,  and UTC  Aerospace
    Systems Service  Concession Request  026-09, Revision  H, dated August
    29, 2018, to repair cracking  found during any inspection required  by
    this paragraph.

(h) NEW REQUIREMENT OF THIS AD: INSTALLATION OF ELBOW RESTRICTOR

    Within 2,000 flight hours or 12 months,  whichever occurs first,  from
    the  effective date  of this AD:  Install  an  elbow  restrictor,  P/N
    46610-1, in accordance with paragraph 3.B., "Procedure," of the Accom-
    plishment  Instructions  of   Bombardier  Service  Bulletin  84-32-69,
    Revision C, dated January 20, 2011.

(i) TERMINATING ACTIONS

(1) Installation of an elbow restrictor  as required  by  paragraph (h) of
    this AD terminates  the repetitive inspection  requirements  of  para-
    graphs (g)(1) and (7) of this AD.

(2) Installation of an elbow restrictor  as required  by  paragraph (h) of
    this AD  terminates the replacement  of  the  forward stabilizer brace
    assembly requirement of paragraph (g)(4)(iii) of this AD.

(j) NEW REQUIREMENT OF THIS AD:  REVISED REPETITIVE INSPECTIONS OF THE MLG
    FORWARD STABILIZER BRACE

(1) Within 2,000 flight cycles  after the installation specified  in para-
    graph (h) of this AD,  or  within 12 months  after the effective date,
    whichever occurs later,  do the non-destructive inspection, in accord-
    ance with Bombardier Repair Drawing 8/4-32-099 Issue 4 dated September
    4, 2018,  and UTC Aerospace Systems Service Concession Request 026-09,
    Revision H, dated August 29, 2018. Thereafter, repeat the non-destruc-
    tive inspection at the times specified in paragraph (j)(2) of this AD.

(2) Repeat the non-destructive inspection  required in paragraph (j)(1) of
    this AD at the applicable intervals  specified in paragraphs (j)(2)(i)
    through (iii) of this AD.

(i) For forward stabilizer braces, P/N 46401-7,  that have not had any re-
    quired rework done,  as specified in Goodrich or UTC Aerospace Systems
    Service  Concession  Request  026-09,  Section C or D,  and  have  had
    Bombardier Service Bulletin 84-32-69  or  Bombardier  Service Bulletin
    84-32-76 incorporated:  Do the non-destructive inspection at intervals
    not to exceed 6,000 flight cycles.

(ii) For forward stabilizer braces P/N 46401-7, that have been reworked in
     accordance with Goodrich or  UTC Aerospace Systems Service Concession
     Request 026-09,  Section D,  and have had Bombardier Service Bulletin
     84-32-69 or Bombardier Service Bulletin 84-32-76 incorporated: Do the
     non-destructive inspection  at  intervals  not to exceed 6,000 flight
     cycles.

(iii) For forward stabilizer braces, P/N 46401-7,  that have been reworked
      in accordance  with Goodrich  or  UTC Aerospace Systems Service Con-
      cession Request 026-09,  Section C,  and have had Bombardier Service
      Bulletin 84-32-69  or  Bombardier Service Bulletin 84-32-76 incorpo-
      rated:  Do the non-destructive inspection at intervals not to exceed
      3,000 flight cycles.

(k) ACCEPTABLE METHOD OF COMPLIANCE FOR PARAGRAPH (H) OF THIS AD

    Replacing the standard elbow fitting  at the retract port  of the lock
    actuator with a new custom elbow fitting in accordance  with paragraph
    3.B.,  "Procedure,"  of the Accomplishment Instructions  of Bombardier
    Service Bulletin 84-32-76,  Revision B,  dated August 1, 2018,  is  an
    acceptable method of compliance for the installation required by para-
    graph (h) of this AD.

(l) CREDIT FOR PREVIOUS ACTIONS

(1) This paragraph provides credit  for actions required  by paragraph (h)
    of this AD,  if those actions were performed before the effective date
    of this AD  using the service information  in one of paragraphs (l)(1)
    (i) through (iii) of this AD.

(i) Bombardier Service Bulletin 84-32-69, dated June 30, 2009.

(ii) Bombardier Service Bulletin 84-32-69,  Revision A,  dated  August 19,
     2009.

(iii) Bombardier Service Bulletin 84-32-69 Revision B, dated September 17,
      2009.

(2) This paragraph provides credit for actions specified  in paragraph (j)
    of this AD,  if those actions were performed before the effective date
    of this AD  using the service information  in one of paragraphs (l)(2)
    (i) through (iii) of this AD.

(i) Bombardier Repair Drawing 8/4-32-099,  Issue 1,  dated March 10, 2009,
    and Goodrich Service Concession Request 026-09 Revision B, dated March
    10, 2009.

(ii) Bombardier Repair Drawing 8/4-32-099, Issue 2,  dated April 20, 2009,
     and  Goodrich  Service Concession Request 026-09,  Revision C,  dated
     April 17, 2009.

(iii) Bombardier Repair Drawing 8/4-32-099 Issue 3, dated December 3, 2009
      and  Goodrich Service Concession Request 026-09,  Revision D,  dated
      November 27, 2009.

(3) This paragraph provides credit for actions performed  using the method
    of compliance specified in paragraph (k) of this AD, if those  actions
    were performed before the effective date of this AD using the  service
    information in paragraph (l)(3)(i) or (ii) of this AD.

(i) Bombardier Service Bulletin 84-32-76, dated May 20, 2010.

(ii) Bombardier Service Bulletin 84-32-76 Revision A, dated June 19, 2014.

(m) OTHER FAA AD PROVISIONS

(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
    local Flight  Standards District  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. AMOCs approved previously in accordance with AD  2009
    -09-02 are  approved as  AMOCs for  the corresponding  requirements in
    paragraph (g) of 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
    Branch, FAA; or TCCA; or Bombardier, Inc.'s TCCA DAO; or De  Havilland
    Aircraft of  Canada Limited's  TCCA DAO.  If approved  by the DAO, the
    approval must include the DAO-authorized signature.

(n) RELATED INFORMATION

(1) Refer   to   Mandatory  Continuing  Airworthiness  Information  (MCAI)
    Canadian AD CF-2009-11R2, dated May 31, 2018, 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-2019-
    0479.

(2) For more information about this AD,  contact Andrea Jimenez, Aerospace
    Engineer,  Airframe and Mechanical Systems Section,  FAA, New York ACO
    Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;  telephone
    516-228-7330; 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 (o)(5)
    and (6) of this AD.

(o) 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.

(3) The following service information was approved  for IBR  on January 9,
    2020.

(i) Bombardier Repair Drawing 8/4-32-099 Issue 4, dated September 4, 2018.

(ii) Bombardier Service Bulletin 84-32-69,  Revision C,  dated January 20,
     2011.

(iii) Bombardier Service Bulletin 84-32-76,  Revision B,  dated  August 1,
      2018.

(iv) UTC Aerospace Systems Service Concession Request 026-09,  Revision H,
     dated August 29, 2018.

(4) The following service information was approved  for IBR on May 6, 2009
    (75 FR 18121, April 21, 2009).

(i) Bombardier Q400 All Operator Message 338, dated February 23, 2009. The
    issue date is specified on only the first page of this document.

(ii) Bombardier Repair Drawing 8/4-32-099, Issue 1,  dated March 10, 2009.
     The issue date is specified on only the first page of this document.

(iii) Goodrich Service Concession Request 026-09, Revision B,  dated March
      10, 2009.  Pages 1 through 8 of  this  document  are  identified  as
      Revision B,  dated March 5, 2009;  pages 9 through 22 are identified
      as Revision B, dated March 10, 2009.

(5) For service information identified  in this AD,  contact  De Havilland
    Aircraft of Canada Limited,  Q-Series Technical Help Desk, 123 Garratt
    Boulevard,  Toronto, Ontario M3K 1Y5, Canada;  telephone 416-375-4000;
    fax   416-375-4539;   email  thd@dehavilland.com;   internet  https://
    dehavilland.com.

(6) You may view this service information at the FAA,  Transport Standards
    Branch,  2200 South 216th St., Des Moines, WA.  For information on the
    availability of this material at the FAA, call 206-231-3195.

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

Issued in Des Moines, Washington,  on November 7, 2019.  Michael Kaszycki,
Acting Director, System Oversight Division, Aircraft Certification Service

FOR FURTHER INFORMATION CONTACT: Andrea Jimenez, Aerospace Engineer,  Air-
frame and Mechanical Systems Section,  FAA,  New  York  ACO  Branch,  1600
Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7330; fax
516-794-5531; email 9-avs-nyaco-cos@faa.gov.