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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. FAA-2004-19943; Directorate Identifier 2004-NM-76-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 757-200 series airplanes. This proposed AD would require modifying the wiring of the test ground signal for the master dim and test system circuit in the flight compartment. This proposed AD is prompted by a report that the master dim and test system circuit does not have wiring separation of the test ground signal for redundant equipment in the flight compartment. We are proposing this AD to prevent a single fault failure during flight, which could result in test patterns instead of the selected radio frequencies showing on the communications panel. These conditions could adversely affect voice and transponder communication capability between the flightcrew and air traffic control, which could result in increased pilot workload. 

# DATES:

We must receive comments on this proposed AD by February 11, 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 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-2004-19943; the directorate identifier for this docket is 2004-NM-76-AD.                     

# FOR FURTHER INFORMATION CONTACT:

*Technical information:*                         Binh Tran, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6485; 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 relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed under                     **ADDRESSES**                    . Include “Docket No. FAA-2004-19943; Directorate Identifier 2004-NM-76-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 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 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 

                    We have received a report indicating that the master dim and test system circuit does not have wiring separation of the test ground signal for redundant equipment in the flight compartment on certain Boeing Model 757-200 series airplanes. This condition could allow a single fault to simulate a test condition in the annunciators, switches, and displays in the flight compartment. A                           ( print page 77676)                        single fault failure could also simulate a test condition on the communications panels and show test patterns instead of the selected radio frequencies. The flightcrew must be aware of the selected radio frequencies used to communicate with air traffic control. If test patterns show on the communications panel during flight, it could adversely affect voice and transponder communication capability between the flightcrew and air traffic control, which could result in increased pilot workload.                 

## Relevant Service Information 

We have reviewed Boeing Service Bulletin 757-33-0050, Revision 2, dated December 4, 2003. The service bulletin describes procedures for modifying the wiring of the test ground signal for the master dim and test system circuit in the flight compartment. The modification includes an operational test. 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 accomplishing the actions specified in the service information described previously. 

## Costs of Compliance 

There are about 55 airplanes of the affected design worldwide, and 30 airplanes of U.S. registry. The proposed modification (including the operational test) would take between 2 and 3 work hours, depending on the airplane configuration, at an average labor rate of $65 per work hour. Required parts cost would be minimal. Based on these figures, the estimated cost of the proposed modification for U.S. operators is between $130 and $195 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 AD. 

## Regulatory Findings 

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will 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-2004-19943; Directorate Identifier 2004-NM-76-AD.                            

## Comments Due Date 

(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by February 11, 2005. 

## Affected ADs 

(b) None. 

## Applicability 

(c) This AD applies to certain Boeing Model 757-200 series airplanes, certificated in any category. 

## Unsafe Condition 

(d) This AD was prompted by a report that the master dim and test system circuit does not have wiring separation of the test ground signal for redundant equipment in the flight compartment. We are issuing this AD to prevent a single fault failure during flight which could result in test patterns instead of the selected radio frequencies showing on the communications panel. These conditions could adversely affect voice and transponder communication capability between the flightcrew and air traffic control, which could result in increased pilot workload. 

## 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) Within 60 months after the effective date of this AD: Modify the wiring of the test ground signal for the master dim and test system circuit in the flight compartment by doing all the applicable actions specified in Boeing Service Bulletin 757-33-0050, Revision 2, dated December 4, 2003. 

## Modifications Done Using Previous Issues of the Service Bulletin 

(g) Modifications done before the effective date of this AD in accordance with Boeing Service Bulletin 757-33-0050, dated August 15, 2002; or Revision 1, dated January 30, 2003; are considered acceptable for compliance with paragraph (f) of 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 in accordance with the procedures found in 14 CFR 39.19. 

Issued in Renton, Washington, on December 7, 2004. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 04-28250 Filed 12-27-04; 8:45 am] 

BILLING CODE 4910-13-P