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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. FAA-2004-19264; Directorate Identifier 2004-NM-90-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 Airbus Model A319, A320, and A321 series airplanes. This proposed AD would require modification of certain auxiliary power unit (APU) alternating current (AC) generators. This proposed AD is prompted by a report of an explosion in the APU compartment, which blew open the compartment doors. We are proposing this AD to prevent oil vapor leakage from the APU AC generator, which, when combined with an electric arc at the electrical receptacle, could result in a fire or explosion in the APU compartment during flight. 

# DATES:

We must receive comments on this proposed AD by November 22, 2004. 

# 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 Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. 

                        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:*                         Tim Dulin, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2141; fax (425) 227-1149.                     

*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 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 relevant written data, views, or arguments regarding this proposed AD. Send your                           ( print page 60099)                        comments to an address listed under                     **ADDRESSES.**                     Include “Docket No. FAA-2004-19264; Directorate Identifier 2004-NM-90-AD” in the subject line 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 that Web site, 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 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 

The Direction Générale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified us that an unsafe condition may exist on certain Airbus Model A319, A320, and A321 series airplanes. The DGAC advises that, one operator reported an explosion in the auxiliary power unit (APU) compartment when passengers were disembarking, which blew open the compartment doors. Analysis revealed that, due to vibrations in the APU alternating current (AC) generators, the retaining bolts of the electrical receptacle had loosened, causing oil vapor leakage. The DGAC also advises that additional reports were received of loose retaining bolts found during maintenance inspections. Oil vapor leakage, combined with an electric arc at the electrical receptacle, could result in a fire or explosion in the APU compartment during flight. 

## Relevant Service Information 

We have reviewed Airbus Service Bulletin A320-24-1106, dated May 26, 2003 (for Model A319, A320, and A321 series airplanes). The service bulletin describes procedures for modification of certain APU AC generators. The modification includes replacing the retaining bolts of the electrical receptacle with new, improved retaining bolts, locking the new bolts with tie wire; installing a new nameplate; and performing an operational test. The service bulletin also specifies modifying the APU AC generator, prior or concurrently with Airbus Service Bulletin A320-24-1082, Revision 01, dated March 15, 1996 (for Model A320 and A321 series airplanes). Accomplishing the actions specified in the Airbus service information is intended to adequately address the unsafe condition. 

The DGAC mandated the Airbus service information and issued French airworthiness directive F-2004-019, dated February 4, 2004, to ensure the continued airworthiness of these airplanes in France. 

Service Bulletin A320-24-1106 refers to Hamilton Sundstrand Service Bulletin 90EGS01AG-24-18, dated February 13, 2003, as an additional source of service information for accomplishment of the modification. 

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

These airplane models are manufactured in France and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DGAC has kept the FAA informed of the situation described above. We have examined the DGACs findings, evaluated all pertinent information, and determined that we need to issue an AD 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 certain APU AC generators. The proposed AD would require you to use the Airbus service information described previously to perform these actions. 

## Costs of Compliance 

This proposed AD would affect about 537 airplanes of U.S. registry. 

For airplanes listed in Service Bulletin A320-24-1106: The proposed modification would take about 5 work hours per airplane, at an average labor rate of $65 per work hour. Required parts would be free of charge. Based on these figures, the estimated cost of the proposed modification for U.S. operators is $174,525, or $325 per airplane. 

For airplanes listed in Service Bulletin A320-24-1082: The concurrent modification, if done, would take about 5 work hours per airplane, at an average labor rate of $65 per work hour. Required parts would be free of charge. Based on these figures, the estimated cost of the proposed modification for U.S. operators is $174,525, or $325 per airplane. 

## 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. 

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: 

      ( print page 60100)    

# 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 airworthiness directive (AD): 

**Airbus:**                                 Docket No. FAA-2004-19264; Directorate Identifier 2004-NM-90-AD.                            

## Comments Due Date 

(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by November 22, 2004. 

## Affected ADs 

(b) None. 

*Applicability:*                                 (c) This AD applies to Airbus Model A319, A320, and A321 series airplanes; certificated in any category; equipped with any Hamilton Sundstrand Auxiliary Power Unit (APU) alternating current (AC) generator having part number 5906732, 5909006, or 5910047; with up to amendment 17 included; on which Airbus Modification 32614 has not been done.                             

## Unsafe Condition 

(d) This AD was prompted by a report of an explosion in the APU compartment which blew open the compartment doors. We are issuing this AD to prevent oil vapor leakage from the APU AC generator, which, when combined with an electric arc at the electrical receptacle, could result in a fire or explosion in the APU compartment during flight. 

*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.                             

## Modification 

(f) For all airplanes: Within 20 months after the effective date of this AD, modify the APU AC generator by doing all the actions specified in the Accomplishment Instructions of Airbus Service Bulletin A320-24-1106, dated May 26, 2003. Do the actions in accordance with the service bulletin. 

## Concurrent Actions 

(g) For Model A320 and A321 series airplanes: Prior to or concurrently with accomplishing the modification required by paragraph (f) of this AD, do the modification of the APU AC generator specified in Airbus Service Bulletin A320-24-1082, Revision 01, dated March 15, 1996; by doing all the actions specified in the Accomplishment Instructions in accordance with the service bulletin. Prior accomplishment of the modification in accordance with Airbus Service Bulletin A320-24-1082, dated September 30, 1994, meets the requirements of this paragraph. 

## Additional Source of Service Information 

# Note 1:

Airbus Service Bulletin A320-24-1106 refers to Hamilton Sundstrand Service Bulletin 90EGS01AG-24-18, dated February 13, 2003, as an additional source of service information for accomplishment of the modification required by paragraph (f) of this AD. 

## Part Installation 

(h) As of the effective date of this AD, no person may install an APU AC generator having a part number listed in the old part number column specified in Paragraph 1.L. of Airbus Service Bulletin A320-24-1106, dated May 26, 2003; on any airplane, unless that generator has been modified in accordance with paragraphs (f) and (g) of this AD, as applicable. 

## Alternative Methods of Compliance (AMOCs) 

(i) The Manager, International Branch, Transport Airplane Directorate, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. 

## Related Information 

(j) French airworthiness directive F-2004-019, dated February 4, 2004, also addresses the subject of this AD. 

Issued in Renton, Washington, on September 30, 2004. 

Kevin M. Mullin, 

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 04-22565 Filed 10-6-04; 8:45 am] 

BILLING CODE 4910-13-P