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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2009-0703; Directorate Identifier 2009-NM-093-AD]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

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

# 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:

There have been four reports of loose or detached main landing gear torque link apex pin locking plate and the locking plate retainer bolt. This condition could result in torque link apex pin disengagement, heavy vibration during landing, damage to main landing gear components and subsequent main landing gear collapse.

* * * * *

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 February 25, 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, Quebec 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-2009-0703; Directorate Identifier 2009-NM-093-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 August 5, 2009 (74 FR 38993). That earlier NPRM proposed to require actions intended to address the unsafe condition for the products listed above.                

Since that earlier NPRM was issued, we have determined that main landing gear (MLG) shock strut assemblies having part number (P/Ns) 49000-11 through 49000-22 inclusive and serial numbers (S/Ns) 0001 through 0284 inclusive are rotable parts. Therefore, the possibility exists that these parts might be installed on additional airplanes. For this reason, we find it necessary to require an inspection to determine if the subject MLG shock strut assemblies are installed for all Model CL-600-2C10 airplanes having S/Ns 10003 and subsequent, and Model CL-600-2D15 and Cl-600-2D24 airplanes having S/Ns 15001 and subsequent. Therefore, for all affected airplanes, we are revising this supplemental NPRM to add an inspection to determine the part and serial numbers of the MLG shock strut assemblies installed.

You may obtain further information by examining the MCAI in the AD docket.

## Comments

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

## Request To Revise Paragraphs (f)(1) and (f)(2) of the Earlier NPRM

American Eagle Airlines (American Eagle) requested that we revise paragraphs (f)(1) and (f)(2) of the earlier NPRM to cover Model CL-600-2C10 airplanes having serial numbers (S/Ns) 10003 and subsequent, equipped with MLG shock strut assemblies having part numbers (P/Ns) 49000-11 through 49000-22 inclusive and S/Ns 0001 through 0252 inclusive. The commenter stated the following:
    - If one of the affected MLG shock strut assemblies were installed on an airplane with a S/N of 10224 or greater, paragraph (f)(1) of the earlier NPRM would not require the assembly to be inspected.
    - If an MLG shock strut assembly that is not in the affected range were installed on an airplane with S/N 10003 through 10223 inclusive, paragraph       ( print page 1557)                          (f)(1) of the earlier NPRM would require the assembly to be inspected in accordance with Part A of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008, and, consequently, with Goodrich Service Bulletin 49000-32-30, which is not applicable to that assembly.                
    - If one of the affected MLG shock strut assemblies were installed on an airplane having a S/N of 10240 or greater, paragraph (f)(2) of the earlier NPRM would not require the assembly to be reworked.
    - If an MLG shock strut assembly not in the affected range were installed on an airplane with S/Ns 10003 through 10239 inclusive, paragraph (f)(2) of the earlier NPRM would require the assembly to be reworked in accordance with Part B of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008, and, consequently, with Goodrich Service Bulletin 49000-32-32, which is not applicable to that assembly.

We agree to revise paragraphs (h) and (i) of this supplemental NPRM (specified as paragraphs (f)(1) and (f)(2) of the earlier NPRM). Operators should note that Model CL-600-2C10 airplanes having S/N 10224 and subsequent had Part A of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008, accomplished prior to delivery; those airplanes are still subject to Part B of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008. Operators should also note that Model CL-600-2C10 airplanes having S/N 10240 and subsequent had Part B of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008, accomplished prior to delivery. However, as explained previously, we have determined that MLG shock strut assemblies having P/Ns 49000-11 through 49000-22 inclusive and S/Ns 0001 through 0284 inclusive are rotable parts. Therefore, the possibility exists that these parts might be installed on additional airplanes, as American Eagle describes.

As stated previously, we revised this supplemental NPRM to add an inspection to identify MLG shock strut assemblies having P/Ns 49000-11 through 49000-22 inclusive and S/Ns 0001 through 0284 inclusive. We also revised paragraphs (h) and (i) of this supplemental NPRM (specified as paragraphs (f)(1) and (f)(2) of the earlier NPRM) to apply to any MLG shock strut assemblies having P/Ns 49000-11 through 49000-22 inclusive and S/Ns 0001 through 0284 inclusive identified during the inspection, as specified in paragraph (g) of this supplemental NPRM. We have also added the costs for accomplishing the newly added inspection specified in paragraph (g) of this supplemental NPRM to the Costs of Compliance section of this supplemental NPRM.

## Request To Allow Installation of Certain Reworked MLG Shock Strut Assemblies

                    American Eagle requested that we revise paragraph (f)(3) of the earlier NPRM to allow the installation of MLG shock strut assemblies that have been reworked in accordance with Goodrich Service Bulletin 49000-32-32. The commenter stated that paragraph (f)(3) of the earlier NPRM prohibits installation of certain MLG shock strut assemblies unless they have been reworked in accordance with Part B of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008. The commenter pointed out that Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008, specifies reworking the subject MLG shock strut assemblies that are installed on the airplanes, not those that are not installed on the airplane (                    *e.g.,*                     spares or replacement assemblies), which will be reworked using Goodrich Service Bulletin 49000-32-32.                

We do not agree that a change to this supplemental NPRM is necessary in this regard. Part B of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008, refers to Goodrich Service Bulletin 49000-32-32 as an additional source of guidance for reworking the MLG shock strut assemblies. If an operator has reworked an MLG shock strut assembly using the procedures specified in Goodrich Service Bulletin 49000-32-32, that assembly meets the requirements of paragraph (j) of this supplemental NPRM (specified as paragraph (f)(3) of the earlier NPRM). However, we have revised paragraph (j) of this supplemental NPRM to refer to paragraph B. of Part B of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008. This change eliminates the necessity of accomplishing the opening and closing procedures specified in Part B of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008, for assemblies that are reworked while not installed on the airplane.

## Request To Provide Credit for Actions Done Using Goodrich Service Information

American Eagle requested that we revise paragraphs (f)(2) and (f)(3) of the earlier NPRM to allow operators to take credit for accomplishing the required actions in accordance with Goodrich Service Bulletin 49000-32-30 or 49000-32-32, as applicable.

We do not agree to provide credit for operators that have done the required actions in accordance with the applicable Goodrich service information. Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008, refers to Goodrich Service Bulletin 49000-32-30 and 49000-32-32 as additional sources of guidance for the actions specified in this supplemental NPRM. If an operator has accomplished the actions specified in Goodrich Service Bulletin 49000-32-30 or 49000-32-32, the operator is already in compliance with the applicable requirements specified in this supplemental NPRM. Therefore, there is no need to revise this supplemental NPRM in this regard.

## Explanation of Additional Changes Made to This Supplemental NPRM

We have revised this supplemental NPRM to identify the legal name of the manufacturer as published in the most recent type certificate data sheet for the affected airplane models.

We have added a new paragraph (f) to this supplemental NPRM to make this supplemental NPRM parallel with other new AD actions. We have reidentified subsequent paragraphs accordingly.

## 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.                          ( print page 1558)    

## 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 Change to Costs of Compliance

Since issuance of the earlier NPRM, we have increased the labor rate used in the Costs of Compliance from $80 per work-hour to $85 per work-hour. The Costs of Compliance information, below, reflects this increase in the specified hourly labor rate.

## 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 5 work-hours per product to comply with the basic requirements of this proposed AD. The average labor rate is $85 per work-hour. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $153,425, or $425 per product.

## 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); and

3. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket.

# 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.

§ 39.13 

2. The FAA amends § 39.13 by adding the following new AD:

**Bombardier, Inc.:**                                 Docket No. FAA-2009-0703; Directorate Identifier 2009-NM-093-AD.                            

## Comments Due Date

(a) We must receive comments by February 25, 2011.

## Affected ADs

(b) None.

## Applicability

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

(1) Model CL-600-2C10 (Regional Jet Series 700, 701 & 702) airplanes, serial numbers (S/Ns) 10003 and subsequent.

(2) Model CL-600-2D15 (Regional Jet Series 705) airplanes and Model CL-600-2D24 (Regional Jet Series 900) airplanes, S/Ns 15001 and subsequent.

## Subject

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

## Reason

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

There have been four reports of loose or detached main landing gear torque link apex pin locking plate and the locking plate retainer bolt. This condition could result in torque link apex pin disengagement, heavy vibration during landing, damage to main landing gear components and subsequent main landing gear collapse.

Investigation has determined that incorrect stack-up tolerances of the apex joint or improper installation of the locking plate and apex nut could result in torque link apex pin disengagement. This directive mandates [a one-time detailed] inspection of the torque link apex joint [for correct installation and damage, and corrective actions if necessary] and replacement of the torque link apex nut.

## 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 for Part Number (P/N) and Serial Number (S/N)

(g) For all airplanes identified in paragraphs (c)(1) and (c)(2) of this AD: Within 900 flight hours after the effective date of this AD, inspect the main landing gear (MLG) shock strut assemblies to determine whether an MLG shock strut assembly having P/Ns 49000-11 through 49000-22 inclusive and a S/N 0001 through 0284 inclusive is installed. A review of airplane maintenance records is acceptable in lieu of this inspection if the part and serial numbers of the MLG shock strut assembly can be conclusively determined from that review.

## Inspection of the Torque Link Apex Joint

(h) For any MLG shock strut assembly having P/Ns 49000-11 through 49000-22 inclusive and a S/N 0001 through 0284 inclusive found installed during the inspection or records check required by paragraph (g) of this AD: Within 900 flight hours after the effective date of this AD, perform a one-time detailed inspection and all applicable corrective actions on the torque link apex joint, in accordance with Part A of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008, except as provided by paragraph (l) of this AD. Do all applicable corrective actions before further flight.

## Replacement or Rework of the Apex Nut

                                (i) For any MLG shock strut assembly identified during the inspection or records check required by paragraph (g) of this AD: Within 4,500 flight hours after the effective date of this AD, replace or rework the apex nut, in accordance with Part B of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008.                                      ( print page 1559)    

## Parts Installation

(j) As of the effective date of this AD, no person may install, on any airplane, a replacement MLG shock strut assembly identified in paragraph (j)(1) or (j)(2) of this AD, unless it has been reworked in accordance with paragraph B. of Part B of the Accomplishment Instructions of Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008.

(1) Part numbers 49000-11 through 49000-22 inclusive, and with a serial number in the range of S/Ns 0001 through 0284 inclusive (the serial number can start with “MA,” “MAL,” or “MA-”).

(2) Part numbers 49050-5 through 49050-10 inclusive, and with a serial number in the range of S/Ns 1001 through 1114 inclusive (the serial number can start with “MA,” “MAL,” or “MA-”).

## Credit for Actions Accomplished in Accordance With Previous Service Information

(k) Inspections, corrective actions, replacements, and rework accomplished before the effective date of this AD in accordance with Bombardier Service Bulletin 670BA-32-019, dated March 16, 2006, are considered acceptable for compliance with the corresponding actions specified in this AD.

(l) The inspections specified in paragraph (h) of this AD are not required if the actions specified in paragraph (i) of this AD have already been accomplished; or if Bombardier Repair Engineering Order 670-32-11-0022, dated October 22, 2005, or Goodrich Service Concession Request SCR 0056-05, dated October 22, 2005; has been incorporated.

## FAA AD Differences

# Note 1: 

The MCAI specifies to inspect only airplanes having certain serial numbers that are part of the MCAI applicability. Because the affected part could be rotated onto any of the airplanes listed in the applicability, this AD requires that the inspection be done on all airplanes. We have coordinated this with the Transport Canada Civil Aviation (TCCA).

## Other FAA AD Provisions

(m) The following provisions also apply to this AD:

                                (1)                                 *Alternative Methods of Compliance (AMOCs):*                                 The Manager, New York Aircraft 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, 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.                            

                                (3)                                 *Reporting Requirements:*                                 A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to be approximately 5 minutes per response, including the time for reviewing instructions, completing and reviewing the collection of information. All responses to this collection of information are mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the burden should be directed to the FAA at: 800 Independence Ave. SW, Washington, DC 20591,                                 *Attn:*                                 Information Collection Clearance Officer, AES-200.                            

## Special Flight Permits

(n) Special flight permits, as described in Section 21.197 and Section 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199), are not allowed.

## Related Information

(o) Refer to MCAI Canadian Airworthiness Directive CF-2009-20, dated May 1, 2009; and Bombardier Service Bulletin 670BA-32-019, Revision A, dated September 18, 2008; for related information.

Issued in Renton, Washington, on December 30, 2010.

Suzanne Masterson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 2011-368 Filed 1-10-11; 8:45 am]

BILLING CODE 4910-13-P