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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2004-19493; Directorate Identifier 2004-NM-69-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 Boeing Model 767-200, -300, and -300F series airplanes. This proposed AD would require replacing the inboard fairing seal common to the vapor barrier seal of each strut assembly. This proposed AD is prompted by discovery during production that a section of vapor barrier seal was missing from the spar web cavities of the upper aft struts of both wings. We are proposing this AD to prevent flammable fluids from leaking onto parts of a hot exhaust system of a shut-down engine of an airplane on the ground, which could result in ignition of the flammable fluids and an uncontained fire. This could also lead to an emergency evacuation of the airplane and possible injury to passengers.

# DATES:

We must receive comments on this proposed AD by December 20, 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 Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

                        You can examine the contents of this AD docket on the Internet at                         *http://dms.dot.gov,*                         or in person 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. This docket number is FAA-2004-19493; the directorate identifier for this docket is 2004-NM-69-AD.                    

# FOR FURTHER INFORMATION CONTACT:

*Technical information:*                         Bernie Gonzalez, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6498; fax (425) 917-6590.                    

*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 written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under                     **ADDRESSES**                    . Include “Docket No. FAA-2004-19493; Directorate Identifier 2004-NM-69-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,                           ( print page 63964)                        business, labor union, etc.). You may review DOT's complete Privacy Act Statement in the                     **Federal Register**                     published on April 11, 2000 (65 FR 19477-78), or you may 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

                    We have received a report indicating that, during production, the manufacturer discovered that a section of vapor barrier seal was missing from the spar web cavities of the left and right upper aft struts on certain Boeing Model 767-200, -300, and -300F series airplanes. The vapor barrier is intended to contain a major spray-type fluid leak and direct the fluid through the upper aft spar web environmental control system penetration and the strut drain system. The existing seal lengths do not completely seal the cavity, which results in a gap that could potentially allow vapors and/or fluids to escape. A major fluid leak (                    *e.g.*, fuel/Skydrol) may overwhelm the drainage provisions for the compartment, filling the compartment and leaking out of the gap. The FAA and Boeing have agreed that, for airplanes in flight and on the ground with the engines running, the fluid can escape safely. However, if an airplane is on the ground with the engines shut down, we are concerned that flammable fluids could leak onto parts of a hot exhaust system of a shut-down engine directly below the missing seal area. This could result in ignition of the flammable fluids and an uncontained fire that could also lead to an emergency evacuation of the airplane and possible injury to passengers.                

## Relevant Service Information

We have reviewed Boeing Service Bulletin 767-54-0107, Revision 1, dated December 18, 2003. The service bulletin describes procedures for replacing the inboard fairing seal common to the vapor barrier seal of each strut assembly with a new seal. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

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

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. Therefore, we are proposing this AD, which would require you to replace the inboard fairing seal common to the vapor barrier seal of each strut assembly with a new seal. The proposed AD would require you to use the service information described previously to perform this action.

## Costs of Compliance

This proposed AD would affect about 311 airplanes of U.S. registry and 756 airplanes worldwide. The proposed actions would take about 4 work hours per airplane, at an average labor rate of $65 per work hour. Required parts would cost about $185 per airplane. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $138,395, or $445 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:

# 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):

**Boeing:**                                 Docket No. FAA-2004-19493; Directorate Identifier 2004-NM-69-AD.                            

## Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by December 20, 2004.

## Affected ADs

(b) None.

## Applicability

(c) This AD applies to Boeing Model 767-200, -300, and -300F series airplanes, equipped with General Electric and Pratt and Whitney engines; as listed in Boeing Service Bulletin 767-54-0107, Revision 1, dated December 18, 2003; certificated in any category.

## Unsafe Condition

(d) This AD was prompted by discovery during production that a section of vapor barrier seal was missing from the spar web cavities of the upper aft struts of both wings. We are issuing this AD to prevent flammable fluids from leaking onto parts of a hot exhaust system of a shut-down engine of an airplane on the ground, which could result in ignition of the flammable fluids and an uncontained fire. This could also lead to an emergency evacuation of the airplane and possible injury to passengers.

## 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.

## Installation of Seal

(f) Within 60 months after the effective date of this AD, replace the inboard fairing seal common to the vapor barrier seal of each strut assembly with a new inboard fairing seal in accordance with the Accomplishment Instructions of Boeing Service Bulletin 767-54-0107, Revision 1, dated December 18, 2003.

## Seal Installations Accomplished per Previous Issue of Service Bulletin

                                (g) Seal installations accomplished in accordance with the Accomplishment                                       ( print page 63965)                                    Instructions of Boeing Service Bulletin 767-54-0107, dated January 16, 2003, are considered acceptable for compliance with the corresponding action specified in this AD.                            

## Alternative Methods of Compliance (AMOCs)

(h) The Manager, Seattle Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

Issued in Renton, Washington, on October 21, 2004.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 04-24540 Filed 11-2-04; 8:45 am]

BILLING CODE 4910-13-P