COMMENTS DUE DATE

(a) We must receive comments by April 12, 2010.

AFFECTED ADS

(b) The proposed AD supersedes AD 2007-14-02, Amendment 39-15124.

APPLICABILITY

(c) This  AD applies  to Bombardier,  Inc. airplanes,  certificated in any
    category, identified in paragraphs (c)(1), (c)(2), and (c)(3) of  this
    AD.

(1) Model CL-600-1A11 (CL-600), serial  numbers 1004 through  1085 inclus-
    ive.

(2) Model CL-600-2A12 (CL-601), serial  numbers  3001 through 3066 inclus-
    ive.

(3) Model CL-600-2B16 (CL-601-3A,  CL-601-3R, and CL-604), serial  numbers
    5001  through 5194  inclusive, and  serial numbers  5301 through  5665
    inclusive.

SUBJECT

(d) Air Transport Association (ATA) of America Code 32: Landing Gear.

REASON

(e) The mandatory continuing airworthiness information (MCAI) states:

"A specific batch of nose landing gear (NLG) and NLG door selector valves,
part number (P/N) 601R75146-1  (Kaiser Fluid Technologies P/N  750006000),
may  have had  their end  caps incorrectly  lock-wired and/or  incorrectly
torqued during assembly.  This condition can  lead to the  end cap backing
off, with  consequent damage  to a  seal and  internal leakage  within the
valve. Subsequently, if  electrical power is  transferred or removed  from
the  aircraft  before  the  NLG safety  pin  is  installed,  any pressure,
including residual pressure, in the  No. 3 hydraulic system can  result in
an uncommanded NLG retraction.

"Although there have been no such cases reported on the Challenger  models
covered by this directive, there have  been six cases reported on the  CRJ
(CL600-2B19) aircraft, one of which resulted in the collapse of the NLG at
the departure gate.

"This directive mandates a check of  the NLG and NLG door selector  valves
installed on all aircraft in the Applicability section * * *. Depending on
the results; replacement, rework  and/or additional identification of  the
valves may be required.

"This [MCAI] revision corrects a Service Bulletin number in the Corrective
Actions table.

"NOTES:

"1. The check is required whether  or not an aircraft has previously  been
    checked  in  accordance  with  AD  CF-2006-16R1  (now  superseded  and
    cancelled by this AD). This is necessary since, following the issuance
    of AD  CF-2006-16R1, it  has been  determined that  the serial  number
    (S/N)  range  of  the  affected  valves  requires  expansion  from the
    previous upper limit of S/N 0767 to S/N 2126 and the exact location of
    each of these additional valves is unknown.

"2. Valves  that have  a S/N  with suffix  `T' have  been manufactured  by
    Tactair Fluid Controls Inc. and do not require any  corrective action.

"3. Valves manufactured by Kaiser Fluid Technologies, P/N 750006000,  with
    S/N 0001 through  2126, and  ink  stamp `SB750006000-1', have  already
    been checked and reworked as necessary  and do not require  any addit-
    ional corrective action.

"4. The Illustrated Parts Catalog, for  each of the models  covered in the
    Applicability section * * *, gives instructions not to install a valve
    manufactured by  Kaiser Fluid  Technologies, P/N  750006000, with  S/N
    0001 through 2126, if the  marking `SB750006000-1' is not ink  stamped
    on the valve.

"5. CL-600-2B16  (CL-605) aircraft,  S/Ns  5701 and  subsequent,  are  not
    affected  by  this directive.  They  were delivered  with  valves, P/N
    750006000, that  have either  a S/N  with suffix  `T' or  have the ink
    stamp marking `SB750006000-1'."

COMPLIANCE

(f) You are responsible for  having the actions  required by this  AD per-
    formed within the compliance times specified, unless the actions  have
    already been done.

RESTATEMENT OF REQUIREMENTS OF AD 2007-14-02 WITH NEW SERVICE  INFORMATION
BUT NO CHANGES TO ACTIONS

INSPECTION AND CORRECTIVE ACTION

(g) For airplanes having  serial numbers (S/Ns) as  identified in the ser-
    vice bulletins specified in Table 1 of this AD, as applicable:  Within
    500 flight  hours or  12 months  after August  16, 2007 (the effective
    date AD 2007-14-02), whichever occurs first, inspect to determine  the
    manufacturer part numbers  (P/Ns) and serial  numbers of the  selector
    valves of the nose landing gear (NLG) and nose gear door. A review  of
    airplane maintenance records is acceptable in lieu of this  inspection
    if  the serial  numbers of  the selector  valves can  be  conclusively
    determined from  that review.  For any  subject selector  valve having
    Tactair Fluid Controls P/N 750006000 and a S/N from 0001 through  0767
    inclusive, before further flight, do related investigative  (including
    a general visual inspection for  proper installation of the lock  wire
    of  the  end  cap)  and corrective  actions;  in  accordance  with the
    applicable service bulletin  identified in Table  1 of this  AD. After
    the  effective  date  of  this AD,  use  only  the  applicable service
    bulletin specified in Table 2 of this AD.

                     TABLE 1--BOMBARDIER SERVICE BULLETINS
--------------------------------------------------------------------------
                          BOMBARDIER SERVICE
          MODEL--             BULLETIN--   REVISION--       DATED--
--------------------------------------------------------------------------
    CL-600-1A11 (CL-600)
    airplanes.......           600-0721       01       February 20, 2006.
    CL-600-2A12 (CL-601),
    and CL-600-2B16            601-0558       01       February 20, 2006.
    (CL-601-3A and
    CL-601-3R) airplanes.
    CL-600-2B16 (CL-604)
    airplanes.......         604-32-021       02       February 20, 2007.
--------------------------------------------------------------------------

    TABLE 2--BOMBARDIER SERVICE BULLETINS FOR PARAGRAPH (G) OF THIS AD
--------------------------------------------------------------------------
                          BOMBARDIER SERVICE
          MODEL--             BULLETIN--   REVISION--       DATED--
--------------------------------------------------------------------------
    CL-600-1A11 (CL-600)
    airplanes.......           600-0721       03       February 23, 2009.
    CL-600-2A12 (CL-601),
    and CL-600-2B16           601-0558        03       February 23, 2009.
    (CL-601-3A and
    CL-601-3R) airplanes.
    CL-600-2B16 (CL-604)
    airplanes.......         604-32-021       04       February 23, 2009.
--------------------------------------------------------------------------

NOTE 1: Operators should be  aware that selector valves having  Bombardier
P/N  601R75146-1  may  be supplied  by  different  manufacturers and  have
different manufacturer part numbers. Only airplanes having selector valves
manufactured by Tactair Fluid Controls, having P/N 750006000, are  subject
to the investigative and corrective actions specified in paragraph (g)  of
this AD.

NOTE 2: For the  purposes of this AD,  a general visual inspection  is: "A
visual  examination  of an  interior  or exterior  area,  installation, or
assembly to detect obvious damage, failure, or irregularity. This level of
inspection  is  made  from  within  touching  distance  unless   otherwise
specified.  A mirror  may be  necessary to  ensure  visual  access to  all
surfaces in the  inspection area. This  level of inspection  is made under
normally available lighting conditions such as daylight, hangar  lighting,
flashlight, or  droplight and  may require  removal or  opening of  access
panels or  doors. Stands,  ladders, or  platforms may  be required to gain
proximity to the area being checked."

NOTE 3: The service  bulletins identified in Table  1 of this AD  refer to
Tactair Fluid Controls Service  Bulletin SB750006000-1, Revision A,  dated
September 6,  2005, as  an additional  source of  service information  for
doing the related  investigative and corrective  actions required by  this
AD.

ACTIONS ACCOMPLISHED ACCORDING TO PREVIOUS ISSUE OF SERVICE BULLETIN

(h) Actions accomplished before August 16, 2007, in accordance  with Bomb-
    ardier Service  Bulletin 604-32-021,  Revision 01,  dated February 20,
    2006  (for  Model  CL-600-2B16  (CL-605)  airplanes),  are  considered
    acceptable for compliance with the corresponding actions specified  in
    paragraph (g) of this AD.

NEW REQUIREMENTS OF THIS AD

ACTIONS

(i) Unless already done, do the following actions.

(1) Within 250 flight hours or within 6 months after the effective date of
    this AD,  whichever occurs  first: Do  an inspection  of the  selector
    valve of the NLG and the  door selector valve of the NLG  to determine
    if  P/N  601R75146-1  (Kaiser  Fluid  Technologies  P/N  750006000) is
    installed, in accordance with  the Accomplishment Instructions of  the
    applicable service bulletin  listed in Table  3 of this  AD. Doing the
    inspection  required  by  this  paragraph  terminates  the  inspection
    required by paragraph (g) of this AD.

     TABLE 3--BOMBARDIER SERVICE BULLETINS FOR ACTIONS IN PARAGRAPH (H)
                               OF THIS AD
--------------------------------------------------------------------------
                          BOMBARDIER SERVICE
          MODEL--             BULLETIN--    REVISION--       DATE--
--------------------------------------------------------------------------
    CL-600-1A11 (CL-600)
    airplanes.......           600-0721        03     February 23, 2009.
    CL-600-2A12 (CL-601),
    and CL-600-2B16            601-0558        03     February 23, 2009.
    (CL-601-3A and
    CL-601-3R) airplanes.
    CL-600-2B16 (CL-604)
    airplanes.......         604-32-021        04     February 23, 2009.
--------------------------------------------------------------------------

(2) If, during any inspection required by paragraph (i)(1) of this AD, any
    selector valve having P/N  601R75146-1 (Kaiser Fluid Technologies  P/N
    750006000) and having a S/N from 0001 through 2126 inclusive without a
    suffix "T" is found, and the valve is not ink-stamped with the marking
    "SB750006000-1": Before further flight, do a general visual inspection
    for proper installation of the lock  wire of the end cap, and  replace
    it with a serviceable selector valve as applicable, in accordance with
    the  Accomplishment Instructions  in the  applicable service  bulletin
    listed in Table 3 of this AD.

(3) Doing the actions before the  effective date of this AD in  accordance
    with the applicable service bulletin listed  in Table 4 of this AD  is
    acceptable for compliance with the corresponding actions specified  in
    this AD.

                    TABLE 4--CREDIT SERVICE BULLETINS
--------------------------------------------------------------------------
      SERVICE BULLETIN           REVISION LEVEL          DATE
--------------------------------------------------------------------------
    Bombardier Service Bulletin        02            June 16, 2008.
    600-0721.
    Bombardier Service Bulletin        02            June 16, 2008.
    601-0558.
    Bombardier Service Bulletin        03            June 16, 2008.
    604-32-021.
--------------------------------------------------------------------------

FAA AD DIFFERENCES

NOTE 4: This  AD differs  from the  MCAI  and/or  service  information  as
follows: No differences.

OTHER FAA AD PROVISIONS

(j) 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.  Send information to  ATTN: Program Manager,  Continuing
    Operational Safety, FAA, New York ACO, 1600 Stewart Avenue, Suite 410,
    Westbury,  New York  11590; telephone  (516) 228-7300;  fax (516)  794
    -5531. Before  using any  approved AMOC  on any  airplane to which the
    AMOC applies,  notify your  principal maintenance  inspector (PMI)  or
    principal  avionics  inspector  (PAI), as  appropriate,  or  lacking a
    principal inspector, your local Flight Standards District Office.  The
    AMOC approval letter must specifically reference this AD.

(2) Airworthy Product: For any requirement in this AD to obtain corrective
    actions from a manufacturer or other source, use these actions if they
    are FAA-approved.  Corrective actions  are considered  FAA-approved if
    they are approved by the State of Design Authority (or their delegated
    agent). You are required to assure the product is airworthy before  it
    is returned to service.

(3) Reporting Requirements: For  any  reporting  requirement  in this  AD,
    under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et
    seq.), the  Office of  Management and  Budget (OMB)  has approved  the
    information  collection  requirements  and  has  assigned  OMB Control
    Number 2120-0056.

RELATED INFORMATION

(k) Refer to MCAI Canadian Airworthiness Directive CF-2009-21R1, dated May
    20, 2009;  Bombardier Service  Bulletin 600-0721,  Revision 03,  dated
    February 23, 2009; Bombardier Service Bulletin 601-0558, Revision  03,
    dated February 23, 2009;  and Bombardier Service Bulletin  604-32-021,
    Revision 04, dated February 23, 2009; for related information.

Issued  in  Renton,  Washington, on  February 17,  2010. Stephen  P. Boyd,
Acting  Manager,  Transport Airplane  Directorate,  Aircraft Certification
Service.

DATES: We must receive comments on this proposed AD by April 12, 2010.