Document ID: FAA-2010-0515-0005
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Bombardier, Inc. Model CL-600-2C10, Model CL-600-2D15 and Model CL-600-2D24 Airplanes
Posted Date: 2011-04-06T04:00Z

[Federal Register Volume 76, Number 66 (Wednesday, April 6, 2011)]
[Proposed Rules]
[Pages 18957-18960]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-8197]

[[Page 18957]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0515; Directorate Identifier 2009-NM-196-AD]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc. Model CL-600-2C10 
(Regional Jet Series 700, 701 & 702), Model CL-600-2D15 (Regional Jet 
Series 705), and Model CL-600-2D24 (Regional Jet Series 900) Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

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

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SUMMARY: We are revising an earlier NPRM for the products listed above. 
This action revises the earlier NPRM by expanding the scope. This 
proposed AD results from mandatory continuing airworthiness information 
(MCAI) originated by an aviation authority of another country to 
identify and correct an unsafe condition on an aviation product. The 
MCAI describes the unsafe condition as:

    Several cases have been reported of cracks in the joint 
extrusions securing the outer bondment to the acoustic panel of the 
nacelle transcowl assemblies. Although there is no effect on flight 
safety (thrust reverser stowed), thrust reverser deployment under 
rejected take-off or emergency landing load conditions could 
potentially result in acoustic panel failure and possible runway 
debris.

* * * * *
The loss of an acoustic panel during rejected take-off or emergency 
landing load conditions could leave debris on the runway. This debris, 
if not removed, creates an unsafe condition for other airplanes during 
take-off or landing, as those airplanes could impact debris on the 
runway and sustain damage. The proposed AD would require actions that 
are intended to address the unsafe condition described in the MCAI.

DATES: We must receive comments on this proposed AD by May 23, 2011.

ADDRESSES: You may send comments 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 W12-40, 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., 400 Cote-Vertu Road West, Dorval, Qu[eacute]bec H4S 
1Y9, Canada; telephone 514-855-5000; fax 514-855-7401; e-mail 
thd.crj@aero.bombardier.com; Internet http://www.bombardier.com. You 
may review copies of the referenced service information at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington. 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; or in person at the Docket Operations office 
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 Operations 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: Craig Yates, Aerospace Engineer, 
Airframe and Mechanical Systems Branch, ANE-171, FAA, New York Aircraft 
Certification Office, 1600 Stewart Avenue, Suite 410, Westbury, New 
York 11590; telephone (516) 228-7355; fax (516) 794-5531.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2010-0515; 
Directorate Identifier 2009-NM-196-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 proposed to amend 14 CFR part 39 with an earlier NPRM for the 
specified products, which was published in the Federal Register on May 
18, 2010 (75 FR 27665). That earlier NPRM proposed to require actions 
intended to address the unsafe condition for the products listed above.
    In paragraph (f)(2) of the original NPRM, we referred to Task 05-
51-27-210-801 of Part 2, Volume 1, of the Bombardier CRJ Series 
Regional Jet Aircraft Maintenance Manual (AMM), CSP B-001, Revision 28, 
dated January 20, 2009, as a source of information for doing the 
inspection of the transcowl assembly. Revision 28 of the AMM does not 
include the inspection. We have revised paragraph (h) of the 
supplemental NPRM (referenced as paragraph (f)(2) in the original NPRM) 
to specify the inspection procedure.
    Transport Canada Civil Aviation (TCCA), which is the aviation 
authority for Canada, has issued Canadian Airworthiness Directive CF-
2009-33, dated July 28, 2009 (referred to after this as ``the MCAI''), 
to correct an unsafe condition for the specified products. The MCAI 
states:

    Several cases have been reported of cracks in the joint 
extrusions securing the outer bondment to the acoustic panel of the 
nacelle transcowl assemblies. Although there is no effect on flight 
safety (thrust reverser stowed), thrust reverser deployment under 
rejected take-off or emergency landing load conditions could 
potentially result in acoustic panel failure and possible runway 
debris.
    This directive mandates inspection, repair (if necessary) and 
reinforcement of the transcowl assemblies.

The loss of an acoustic panel during rejected take-off or emergency 
landing load conditions could leave debris on the runway. This debris, 
if not removed, creates an unsafe condition for other airplanes during 
take-off or landing, as those airplanes could impact debris on the 
runway and sustain damage. The inspection is a detailed visual 
inspection of the outboard edge of the transcowl joint extrusion for 
evidence of cracking. The repair consists of doing an eddy current or 
liquid penetrant inspection for cracking, and depending on the results, 
either removing the affected joint extrusion area and replacing with 
packers, or contacting Bombardier for repair instructions and doing the 
repair. The reinforcement of the transcowl assemblies includes 
installing new support channels. You may obtain further information by 
examining the MCAI in the AD docket.

[[Page 18958]]

Relevant Service Information

    Bombardier has issued Service Bulletin 670BA-78-008, Revision B, 
dated December 22, 2010; and Service Bulletin 670SH-78-029, Revision C, 
dated November 10, 2010. The actions described in this service 
information are intended to correct the unsafe condition identified in 
the MCAI.

Comments

    We have considered the following comments received on the earlier 
NPRM.

Requests To Refer to Latest Task Revision of AMM

    Comair, Inc. (Comair) and Mesa Airlines (Mesa) both requested that 
we include the latest revision of the AMM task or a statement to 
account for the current AMM release for the task proposed in the 
original NPRM. Comair explained that the latest AMM task revisions are 
at Revisions 29 and 30, and Mesa explained that the AMM task is up to 
Revision 31, dated March 20, 2010.
    We partially agree with the request to refer to the latest revision 
of the AMM task. We agree that later revisions of the AMM task are more 
appropriate to the actions proposed in the original NPRM. However, 
instead of referring to the latest revisions of the AMM task in the 
supplemental NPRM, we have revised paragraph (h) of the supplemental 
NPRM to spell out the required actions, thus eliminating the need to 
request an alternative method of compliance (AMOC) every time the AMM 
is updated. A reference to Revision 34, dated November 20, 2010, to the 
AMM task as an additional source of guidance is provided in Note 1 of 
the supplemental NPRM.

Request To Require Only Part 3 of the AMM Task

    Comair requested that we revise the original NPRM to refer only to 
Part 3 of AMM Task 05-51-27-210-810. Comair reasoned that Part 1 and 
Part 2 do not pertain to the subject of the unsafe condition addressed 
by the original NPRM and should not be mandated through the AD process.
    We assume Comair is referring to AMM Task 05-51-27-201-801. While 
we disagree with the request to refer to ``Procedure--Part 3,'' in the 
required actions in the supplemental NPRM, we have included this 
reference in Note 1 of the Supplemental NPRM. As discussed above, the 
supplemental NPRM specifies the required actions instead of referring 
to a specific AMM task revision, thus eliminating the need for section 
identification as new revisions to the AMM are released. We have not 
revised the supplemental NPRM in this regard.

Request To Define High-Energy Stop (HES) or Rejected Take-Off (RTO)

    Comair requested that we define the terms HES and RTO in the 
original NPRM because inspections should not be mandated if the RTO/HES 
occurs outside certain parameters. Comair explained that an RTO might 
occur at any speed and not require any braking or deployment of the 
thrust reverser. Comair stated that Revision 30 of AMM Task 05-51-27-
210-807, defines when the joint extrusion of the transcowl assemblies 
need to be inspected as follows:
     If an RTO occurs and thrust reversers are deployed above 
68% N1.
     If during an HES, the thrust reversers are deployed above 
68% N1.
    We infer that Comair is referring to AMM Task 05-51-27-210-801, 
which calls out the conditions to proceed, as Comair suggests, in Part 
3 of the AMM task, ``Examination of the Joint Extrusion of the 
Transcowl Assemblies.'' We agree with the request to define RTO and HES 
for the reasons Comair stated. We have revised paragraph (h) of the 
supplemental NPRM (paragraph (f)(2) of the original NPRM) accordingly.

Request for Inclusion of Post-Serviceable Part Numbers

    Mesa requested that we revise the original NPRM to include post-
serviceable part numbers KCN624-2003-4, -6, or -8.
    We agree to include post-serviceable part numbers KCN624-2003-4, -
6, or -8 in the supplemental NPRM. Part numbers KCN624-2003-4, -6, and 
-8 are listed in paragraph 1.N., ``Relationship Chart,'' of Bombardier 
Service Bulletin 670SH-78-029, Revision C, dated November 10, 2010, 
which is an additional source of service information for the actions 
specified in Bombardier Service Bulletin 670BA-78-008, Revision B, 
dated December 22, 2010. We have revised paragraph (g)(1)(i) of the 
supplemental NPRM accordingly.

Request for Inclusion of Credit Service Information

    Mesa requested that we revise paragraphs (f)(1)(ii), (f)(3), 
(f)(4), and (f)(5) of the original NPRM to include Bombardier Service 
Bulletin 670SH-78-029, dated July 3, 2008; Revision A, dated June 30, 
2009; and Revision B, dated November 25, 2009; as a source of service 
information.
    We agree to revise the supplemental NPRM to give credit to those 
operators who have done the actions in accordance with Bombardier 
Service Bulletin 670SH-78-029, dated July 3, 2008; Revision A, dated 
June 30, 2009; and Revision B, dated November 25, 2009. We have revised 
paragraph (i) of the supplemental NPRM (paragraph (f)(4) of the 
original NPRM), accordingly. Paragraphs (g)(2), (i), and (k) of the 
supplemental NPRM (paragraphs (f)(1)(ii), (f)(3), and (f)(5) of the 
original NPRM) refer to the latest revisions of the service 
information. While Mesa and Bombardier referred to Bombardier Service 
Bulletin 670SH-78-029, Revision A, dated July 29, 2009, June 30, 2009, 
is the appropriate date for Revision A of Bombardier Service Bulletin 
670SH-78-029.

FAA's Determination and Requirements of This Proposed AD

    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 earlier 
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 proposed AD.

Differences Between This AD and the MCAI or Service Information

    We have reviewed the MCAI and related service information and, in 
general, agree with their substance. But we might have found it 
necessary to use different words from those in the MCAI to ensure the 
AD is clear for U.S. operators and is enforceable. In making these 
changes, we do not intend to differ substantively from the information 
provided in the MCAI and related service information.
    We might also have proposed different actions in this AD from those 
in the MCAI in order to follow FAA policies. Any such differences are 
highlighted in a Note within the proposed AD.

Explanation of Additional Paragraph in the Supplemental NPRM

    We have added a new paragraph (f) to this supplemental NPRM to 
clarify the responsibility for performing the

[[Page 18959]]

proposed actions within the specified compliance times. We have re-
identified subsequent paragraphs accordingly.

Costs of Compliance

    Based on the service information, we estimate that this proposed AD 
would affect about 361 products of U.S. registry. We also estimate that 
it would take about 8 work-hours per product to comply with the basic 
requirements of this proposed AD. The average labor rate is $85 per 
work-hour. Required parts would cost about $0 per product. Where the 
service information lists required parts costs that are covered under 
warranty, we have assumed that there will be no charge for these costs. 
As we do not control warranty coverage for affected parties, some 
parties may incur costs higher than estimated here. Based on these 
figures, we estimate the cost of the proposed AD on U.S. operators to 
be $245,480, or $680 per product.
    In addition, we estimate that any necessary follow-on actions would 
take between 4 and 8 work-hours and require parts costing $0, for a 
cost between $340 and $680 per product. We have no way of determining 
the number of products that may need these actions.

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 
rulemaking 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 AD:

Bombardier, Inc.: Docket No. FAA-2010-0515; Directorate Identifier 
2009-NM-196-AD.

Comments Due Date

    (a) We must receive comments by May 23, 2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to the airplanes identified in paragraphs 
(c)(1) and (c)(2) of this AD, certificated in any category.
    (1) Bombardier, Inc. Model CL-600-2C10 (Regional Jet Series 700, 
701, & 702) airplanes, serial numbers 10003 through 10265 inclusive.
    (2) Bombardier, Inc. Model CL-600-2D15 (Regional Jet Series 705) 
and Model CL-600-2D24 (Regional Jet Series 900) airplanes, serial 
numbers 15001 through 15192 inclusive.

Subject

    (d) Air Transport Association (ATA) of America Code 78: Engine 
exhaust.

Reason

    (e) The mandatory continuing airworthiness information (MCAI) 
states:
    Several cases have been reported of cracks in the joint 
extrusions securing the outer bondment to the acoustic panel of the 
nacelle transcowl assemblies. Although there is no effect on flight 
safety (thrust reverser stowed), thrust reverser deployment under 
rejected take-off or emergency landing load conditions could 
potentially result in acoustic panel failure and possible runway 
debris.
* * * * *
    The loss of an acoustic panel during rejected take-off or 
emergency landing load conditions could leave debris on the runway. 
This debris, if not removed, creates an unsafe condition for other 
airplanes during take-off or landing, as those airplanes could 
impact debris on the runway and sustain damage.

Compliance

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

Inspection, Repair, and Reinforcement

    (g) Within 5,000 flight hours or 24 months after the effective 
date of this AD, whichever occurs first, inspect for the part number 
and serial number of each transcowl assembly, and, as applicable, 
the repair status of each transcowl assembly.
    (1) If all transcowl assemblies installed on any airplane meet 
one of the conditions listed in paragraph (g)(1)(i), (g)(1)(ii), or 
(g)(1)(iii) of this AD, no further action is required by this AD, 
except paragraphs (h) and (k) of this AD must be complied with.
    (i) Having part number (P/N) KCN624-2003-3, -4, -5, -6, -7, or -
8, as listed in Bombardier Service Bulletin 670SH-78-029, Revision 
C, dated November 10, 2010.
    (ii) Having P/Ns CN624-2001-XXX or KCN624-2001-X (XXX and X mean 
various dash numbers), with serial number (S/N) SB0965 or higher.
    (iii) Having P/Ns CN624-2001-XXX or KCN624-2001-X (XXX and X 
mean various dash numbers), and repaired in accordance with one of 
the Bombardier repair engineering orders (REOs) listed in paragraph 
1.D. of Bombardier Service Bulletin 670BA-78-008, Revision B, dated 
December 22, 2010; or paragraph 1.A. of Bombardier Service Bulletin 
670SH-78-029, Revision C, dated November 10, 2010.
    (2) If one or more of the transcowl assemblies have P/N CN624-
2001-XXX or KCN624-2001-X (XXX and X mean various dash numbers), 
with S/N SB0964 or lower, and have not been repaired in accordance 
with one of the Bombardier REOs listed in paragraph 1.D. of 
Bombardier Service Bulletin 670BA-78-008, Revision B, dated December 
22, 2010; or paragraph 1.A. of Bombardier Service Bulletin 670SH-78-
029, Revision C, dated November 10, 2010; do the actions specified 
in paragraph (i) of this AD.
    (h) As of the effective date of this AD, if any high-energy stop 
occurs and the thrust reversers are deployed above 68% N1; or if a 
rejected take-off (RTO) occurs and the thrust reversers are deployed 
above 68% N1; perform a detailed inspection for cracks of each 
transcowl assembly (left, right, upper, and lower) before further 
flight, by doing the actions specified in paragraphs (h)(1), (h)(2), 
and (h)(3) of this AD. Doing the requirements of paragraph (i) of 
this AD terminates the requirements of paragraph (h) of this AD.
    (1) Open the cowling on the left and right engines.

[[Page 18960]]

    (2) Do a detailed inspection for cracks of the joint extrusion 
of the upper and lower transcowl assembly on the left and right 
engines at the location of the joint piece. If no cracks are found, 
close the cowlings on the left and right engines.
    (3) If any crack is found on one or more transcowl assemblies 
during the inspection required by paragraph (h)(2) of this AD, 
before further flight, repair and reinforce the cracked part(s) in 
accordance with paragraph (i)(1) of this AD.

    Note 1:  Procedure-Part 3 of Task 05-51-27-210-801 of Part 2, 
Volume 1, of the Bombardier CRJ Series Regional Jet AMM, CSP B-001, 
Revision 34, dated November 20, 2010, gives guidance for opening and 
closing the cowling on the left and right engines.

    (i) For transcowl assemblies identified in paragraph (g)(2) of 
this AD: Except as required by paragraph (h) of this AD, within 
5,000 flight hours or 24 months after the effective date of this AD, 
whichever comes first, do a detailed inspection for cracking on each 
transcowl assembly, in accordance with the Accomplishment 
Instructions of Bombardier Service Bulletin 670BA-78-008, Revision 
B, dated December 22, 2010; or Bombardier Service Bulletin 670SH-78-
029, Revision C, dated November 10, 2010. Accomplishment of the 
actions specified in paragraph (i)(1) or (i)(2) of this AD for all 
transcowl assemblies identified in paragraph (g)(2) of this AD 
terminates the requirements of paragraph (h) of this AD.
    (1) If any cracking of the joint extrusion is found, before 
further flight, repair and reinforce the joint extrusion on each 
transcowl assembly, in accordance with the Accomplishment 
Instructions of Bombardier Service Bulletin 670BA-78-008, Revision 
B, dated December 22, 2010; or Bombardier Service Bulletin 670SH-78-
029, Revision C, dated November 10, 2010.
    (2) If no cracking is found, before further flight, reinforce 
the joint extrusion on each transcowl assembly, in accordance with 
the Accomplishment Instructions of Bombardier Service Bulletin 
670BA-78-008, Revision B, dated December 22, 2010; or Bombardier 
Service Bulletin 670SH-78-029, Revision C, dated November 10, 2010.

Credit for Actions Accomplished in Accordance with Previous Service 
Information

    (j) Inspections, repairs, and reinforcement of the joint 
extrusion on each transcowl is also acceptable for compliance with 
the corresponding requirements of paragraph (i) of this AD if done 
before the effective date of this AD in accordance with the service 
information listed in table 1 of this AD.

                                          Table 1--Service Information
----------------------------------------------------------------------------------------------------------------
                 Document                            Revision                              Date
----------------------------------------------------------------------------------------------------------------
Bombardier Service Bulletin 670BA-78-008.  Original....................  September 19, 2008.
Bombardier Service Bulletin 670BA-78-008.  A...........................  July 10, 2009.
Bombardier Service Bulletin 670SH-78-029.  Original....................  July 3, 2008.
Bombardier Service Bulletin 670SH-78-029.  A...........................  June 30, 2009.
Bombardier Service Bulletin 670SH-78-029.  B...........................  November 25, 2009.
----------------------------------------------------------------------------------------------------------------

Parts Installation

    (k) As of the effective date of this AD, no replacement or spare 
transcowl assembly having P/N CN624-2001-XXX or KCN624-2001-X (XXX 
and X mean various dash numbers), with S/N SB0964 or lower, may be 
installed on any airplane, except for a transcowl assembly on which 
any repair listed in paragraph 1.D. of Bombardier Service Bulletin 
670BA-78-008, Revision B, dated December 22, 2010, or paragraph 1.A. 
of Bombardier Service Bulletin 670SH-78-029, Revision C, dated 
November 10, 2010, has been done; and except for a transcowl that 
has been inspected as specified in paragraph (i) of this AD and all 
applicable actions specified in paragraph (i)(1) or (i)(2) of this 
AD, as applicable, have been done.

FAA AD Differences

    Note 2:  This AD differs from the MCAI and/or service 
information as follows: No differences.

Other FAA AD Provisions

    (l) The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager, New 
York Aircraft Certification Office, 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, 1600 Stewart Avenue, Suite 40, 
Westbury, N.Y. 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) 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.

Related Information

    (m) Refer to MCAI Canadian Airworthiness Directive CF-2009-33, 
dated July 28, 2009; Bombardier Service Bulletin 670BA-78-008, 
Revision B, dated December 22, 2010; and Bombardier Service Bulletin 
670SH-78-029, Revision C, dated November 10, 2010; for related 
information.

    Issued in Renton, Washington, on March 24, 2011.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-8197 Filed 4-5-11; 8:45 am]
BILLING CODE 4910-13-P