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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2011-1416; Directorate Identifier 2011-NM-156-AD]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Notice of proposed rulemaking (NPRM).

# SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model CL-600-2C10 (Regional Jet Series 700, 701, & 702); CL-600-2D15 (Regional Jet Series 705); CL-600-2D24 (Regional Jet Series 900); and CL-600-2E25 (Regional Jet Series 1000) airplanes. This proposed AD was prompted by reports of deformation of the pressure regulator on the oxygen cylinder, which was attributed to batches of raw material that did not meet required tensile strength. This proposed AD would require an inspection to determine if certain oxygen pressure regulators are installed, and replacement of oxygen cylinder and regulator assemblies (CRAs) containing pressure regulators that do not meet required material properties. We are proposing this AD to prevent elongation of the pressure regulator neck, which could result in rupture of the oxygen cylinder, and in the case of cabin depressurization, oxygen would not be available when required.

# DATES:

We must receive comments on this proposed AD by March 5, 2012.

# 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 W12-140, 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., 400 Côte-Vertu Road West, Dorval, Québec H4S 1Y9, Canada; telephone (514) 855-5000; fax (514) 855-7401; email                         *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:

Cesar Gomez, Aerospace Engineer, Airframe and Mechanical Systems Branch, ANE-171, FAA, New York Aircraft Certification Office (ACO), 1600 Stewart Avenue, Suite 410, Westbury, New York 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 proposed AD. Send your comments to an address listed under the                     **ADDRESSES**                     section. Include “Docket No. FAA-2011-1416; Directorate Identifier 2011-NM-156-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.                          ( print page 2663)    

## Discussion

Transport Canada Civil Aviation (TCCA), which is the aviation authority for Canada, has issued Canadian Airworthiness Directive CF-2011-28, dated July 28, 2011 (referred to after this as “the MCAI”), to correct an unsafe condition for the specified products. The MCAI states:

During a routine inspection, deformation was found at the neck of the pressure regulator body on the oxygen Cylinder and Regulator Assemblies (CRA) of a BD-700-1A11 aeroplane.

An investigation by the vendor, Avox Systems Inc., revealed that the deformation was attributed to two (2) batches of raw material that did not meet the required tensile strength. This may cause elongation of the pressure regulator neck, which could result in rupture of the oxygen cylinder, and in the case of cabin depressurization, oxygen would not be available when required.

Although there have been no reported failures to date on any CL-600-2C10, CL-600-2D15, CL-600-2D24 or CL-600-2E25 aeroplanes, similar oxygen pressure regulators, Part Number (P/N) 806370-06, could also be installed on the aeroplanes listed in the Applicability section of this [TCCA] directive.

This [TCCA] directive mandates [an inspection for certain serial numbers, and if necessary, replacement of the affected oxygen CRA in accordance with the accomplishment instructions of Bombardier Service Bulletin 670BA-35-011, dated July 5, 2011; and] the replacement of oxygen CRAs containing pressure regulators that do not meet the required material properties.

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

## Relevant Service Information

Bombardier has issued Service Bulletin 670BA-35-011, dated July 5, 2011. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.

## 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.

## Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 263 products of U.S. registry. We also estimate that it would take about 2 work-hours per product to comply with the basic requirements of this proposed AD. The average labor rate is $85 per work-hour. Where the service information lists required parts costs that are covered under warranty, we have assumed that there will be no charge for these parts. 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 $44,710, or $170 per product.

In addition, we estimate that any necessary follow-on actions would take about 1 work-hour and require parts costing $0, for a cost of $85 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.

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-2011-1416; Directorate Identifier 2011-NM-156-AD.                            

## (a) Comments Due Date

We must receive comments by March 5, 2012.

## (b) Affected ADs

None.

## (c) Applicability

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

(1) Bombardier, Inc. Model CL-600-2C10 (Regional Jet Series 700, 701, & 702) airplanes, serial numbers 10002 through 10999 inclusive.

(2) Bombardier, Inc. Model CL-600-2D15 (Regional Jet Series 705) and CL-600-2D24 (Regional Jet Series 900) airplanes, serial numbers 15001 through 15990 inclusive.

(3) Bombardier, Inc. Model CL-600-2E25 (Regional Jet Series 1000) airplanes, serial numbers 19001 through 19990 inclusive.

## (d) Subject

Air Transport Association (ATA) of America Code 35: Oxygen.

## (e) Reason

                                This AD was prompted by reports of deformation of the pressure regulator on the oxygen cylinder, which was attributed to batches of raw material that did not meet required tensile strength. We are issuing this                                       ( print page 2664)                                    AD to prevent elongation of the pressure regulator neck, which could result in rupture of the oxygen cylinder, and in the case of cabin depressurization, oxygen would not be available when required.                            

## (f) Compliance 

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

## (g) Actions 

Within 1,800 flight hours or 6 months after the effective date of this AD, whichever occurs first: Inspect the serial number of each oxygen pressure regulator, part number (P/N) 806370-06, to determine if the serial number of the regulator is listed in “Table 2, Regulators” of paragraph 1.A.(1) of Bombardier Service Bulletin 670BA-35-011, dated July 5, 2011. If the serial number of the oxygen pressure regulator, P/N 806370-06, is listed in “Table 2, Regulators” of paragraph 1.A.(1) of Bombardier Service Bulletin 670BA-35-011, dated July 5, 2011, before further flight: Replace the affected oxygen cylinder and regulator assembly (CRA), in accordance with the Accomplishment Instructions of Bombardier Service Bulletin 670BA-35-011, dated July 5, 2011. 

## (h) Parts Installation 

As of the effective date of this AD, no person may install an oxygen pressure regulator, P/N 806370-06, having a serial number listed in “Table 2, Regulators” of paragraph 1.A.(1) of Bombardier Service Bulletin 670BA-35-011, dated July 5, 2011, on any airplane unless the serial number of the CRA and pressure regulator have a suffix “A” beside the serial number. 

## (i) Other FAA AD Provisions 

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. 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, 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.                             

## (j) Related Information 

Refer to MCAI Canadian Airworthiness Directive CF-2011-28, dated July 28, 2011; and Bombardier Service Bulletin 670BA-35-011, dated July 5, 2011; for related information.

Issued in Renton, Washington, on January 6, 2012. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 2012-857 Filed 1-18-12; 8:45 am] 

BILLING CODE 4910-13-P