Document Headings

                    Document headings vary by document type but may contain                    the following:                  
                -                       the agency or agencies that issued and signed a document                    
                -                       the number of the CFR title and the number of each part                      the document amends, proposes to amend, or is directly                      related to                    
                -                       the agency docket number / agency internal file number                    
                -                       the RIN which identifies each regulatory action listed in                      the Unified Agenda of Federal Regulatory and Deregulatory                      Actions                    

                    See the                                          Document Drafting Handbook                                        for more details.                  

###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2004-19761; Directorate Identifier 2003-NM-167-AD]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Notice of proposed rulemaking (NPRM).

# SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 and 440) airplanes. This proposed AD would require modification of the Auxiliary Power Unit (APU) cooling air exhaust. This proposed AD is prompted by reports of incomplete drainage of the APU enclosure. We are proposing this AD to prevent a negative pressure condition from developing in the APU enclosure when the APU is operating on the ground, which could create a potential fire hazard if flammable liquid leakage occurs inside the APU enclosure and cannot be drained overboard.

# DATES:

We must receive comments on this proposed AD by January 6, 2005.

# ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.
      - DOT Docket Web site: Go to http://dms.dot.gov                          and follow the instructions for sending your comments electronically.                    
      - Government-wide rulemaking web site: Go to http://www.regulations.gov                          and follow the instructions for sending your comments electronically.                    
      - Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, room PL-401, Washington, DC 20590.
      - By fax: (202) 493-2251.
      - Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., 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., Canadair, Aerospace Group, P.O. Box 6087, Station Centre-ville, Montreal, Quebec H3C 3G9, Canada.

                        You can examine the contents of this AD docket on the Internet at                         *http://dms.dot.gov,*                         or at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC.                    

# FOR FURTHER INFORMATION CONTACT:

*Technical information:*                         James E. Delisio, Aerospace Engineer, Airframe and Propulsion Branch, ANE-171, FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, suite 410, Westbury, New York 11590; telephone (516) 228-7321; fax (516) 794-5531.                    

*Plain Language information:*                         Marcia Walters,                         *Marcia.walters@faa.gov.*

# SUPPLEMENTARY INFORMATION:

## Docket Management System (DMS)

                    The FAA has implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, new                           ( print page 70567)                        AD actions are posted on DMS and assigned a docket number. We track each action and assign a corresponding directorate identifier. The DMS AD docket number is in the form “Docket No. FAA-2004-99999.” The Transport Airplane Directorate identifier is in the form “Directorate Identifier 2004-NM-999-AD.” Each DMS AD docket also lists the directorate identifier (“Old Docket Number”) as a cross-reference for searching purposes.                

## Comments Invited

                    We invite you to submit any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under                     **ADDRESSES.**                     Include “Docket No. FAA-2004-19761; Directorate Identifier 2003-NM-167-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments submitted by the closing date and may amend the proposed AD in light of those comments.                

                    We will post all comments we receive, without change, to                     *http://dms.dot.gov,*                     including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of our docket website, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You can review the DOT's complete Privacy Act Statement in the                     **Federal Register**                     published on April 11, 2000 (65 FR 19477-78), or you can visit                     *http://dms.dot.gov.*

                    We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You can get more information about plain language at                     *http://www.faa.gov/​language*                     and                     *http://www.plainlanguage.gov.*

## Examining the Docket

                    You can examine the AD docket on the Internet at                     *http://dms.dot.gov*, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the                     **ADDRESSES**                     section. Comments will be available in the AD docket shortly after the DMS receives them.                

## Discussion

Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, notified us that an unsafe condition may exist on certain Bombardier Model CL-600-2B19 (Regional Jet series 100 & 440) airplanes. TCCA advises that incomplete drainage of the APU enclosure has been reported in service. Further investigation revealed that negative pressure, which may contribute to the drainage problem, could be created in the APU enclosure when the APU is operating on the ground. This condition, if not corrected, could create a potential fire hazard if flammable liquid leakage occurs inside the APU enclosure and cannot be completely drained overboard.

## Relevant Service Information

Bombardier has issued Service Bulletin S.B. 601R-49-015, including Appendix A, dated November 6, 1998, which describes procedures for modification of the APU cooling air exhaust. This modification corrects the negative pressure problem and increases the volume of air entering the APU enclosure. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. TCCA mandated the service information and issued Canadian airworthiness directive CF-2002-21, dated March 21, 2002, to ensure the continued airworthiness of these airplanes in Canada.

Bombardier Service Bulletin S.B. 601R-49-015 refers to Avica Service Bulletin 10S145-49-01, dated July 15, 1998, and Canadair Kit Drawing K601R97150, Rev NC, as additional sources of service information for doing the modification. The Avica service bulletin and the Canadair Kit Drawing are included as Appendix A of the Bombardier service bulletin.

## FAA's Determination and Requirements of the Proposed AD

This airplane model is manufactured in Canada and is type certificated for operation in the United States under the provisions of § 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, TCCA has kept the FAA informed of the situation described above. We have examined TCCA's findings, evaluated all pertinent information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Therefore, we are proposing this AD, which would require modification of the APU cooling air exhaust. The proposed AD would require you to use the Bombardier service information described previously to perform these actions.

## Differences Between the Bombardier Service Bulletin and This Proposed AD

Although the Accomplishment Instructions of the Bombardier service bulletin indicate to submit a comment sheet and a compliance sheet, this proposed AD does not require that action.

## Costs of Compliance

This proposed AD would affect about 120 airplanes of U.S. registry. The proposed actions would take about 10 work hours per airplane, at an average labor rate of $65 per work hour. There would be no charge for parts that may be required to perform the actions required by this AD. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $78,000, or $650 per airplane.

## Authority for This Rulemaking

The FAA's authority to issue rules regarding aviation safety is found in Title 49 of the United States Code. 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.

This rulemaking is promulgated under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, the FAA is charged with promoting safety 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 proposed AD.

## Regulatory Findings

                    We have 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.                          ( print page 70568)    

For the reasons discussed above, I certify that the 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. See the                     **ADDRESSES**                     section for a location to examine the regulatory evaluation.                

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - 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 Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

**Bombardier, Inc. (Formerly Canadair):**                                 Docket No. FAA-2004-19761; Directorate Identifier 2003-NM-167-AD.                            

## Comments Due Date

(a) The FAA must receive comments on this AD action by January 6, 2005.

## Affected ADs

(b) None.

## Applicability

(c) This AD applies to Bombardier Model CL-600-2B19 (Regional Jet Series 100 and 440) airplanes, certificated in any category, as identified in Bombardier Service Bulletin S.B. 601R-49-015, including Appendix A, dated November 6, 1998.

## Unsafe Condition

(d) This AD is prompted by reports of incomplete drainage of the Auxiliary Power Unit (APU) enclosure. We are issuing this AD to prevent a negative pressure condition from developing in the APU enclosure when the APU is operating on the ground, which could create a potential fire hazard if flammable fluid leakage occurs inside the APU enclosure and cannot be drained overboard.

## Compliance

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

## Modify APU Cooling Air Exhaust

(f) Within 2,000 flight hours after the effective date of the AD, or within 16 months after the effective date of this AD, whichever occurs first: Modify the APU cooling air exhaust by doing all of the actions in the Accomplishment Instructions of Bombardier Service Bulletin S.B. 601R-49-015, dated November 6, 1998, except that submitting a comment sheet and a compliance sheet are not required by this AD.

# Note 1:

Bombardier Service Bulletin S.B. 601R-49-015, dated November 6, 1998, refers to Avica Service Bulletin 10S145-49-01, dated July 15, 1998, and Canadair Kit Drawing K601R97150, Rev NC, as additional sources of service information for doing the modification. The Avica service bulletin and the Canadair Kit Drawing are included as Appendix A of the Bombardier service bulletin. 

## Parts Installation

(g) As of the effective date of this AD, no person may install an APU enclosure having Canadair part number (P/N) 601R97150-13, or Avica P/N 15A104-101, on any airplane, unless the unit has been modified in accordance with paragraph (f) of this AD.

## Alternative Methods of Compliance

(h) The Manager, New York Aircraft Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19.

## Related Information

(i) Transport Canada Civil Aviation Canadian airworthiness directive CF-2002-21, dated March 21, 2002, also addresses the subject of this AD.

Issued in Renton, Washington, on November 26, 2004.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 04-26798 Filed 12-6-04; 8:45 am]

BILLING CODE 4910-13-P