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[Federal Register Volume 69, Number 188 (Wednesday, September 29, 2004)]
[Proposed Rules]
[Pages 58109-58111]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-21818]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19203; Directorate Identifier 2004-NM-109-AD]
RIN 2120-AA64

Airworthiness Directives; Boeing Model 757-200 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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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 frequency converters located in the closet 
assembly in the passenger compartment, and making various wiring 
changes in and between the closet assembly and forward purser work 
station. This proposed AD also would require modifying the in-flight 
entertainment system prior to or concurrently with the modification of 
the frequency converters. This proposed AD is prompted by a 
certification review that revealed a frequency converter failure mode 
not identified in the original system design. We are proposing this AD 
to prevent a short circuit between the frequency converter output and 
the distribution circuit breakers, which could result in overheating 
and failure of adjacent wiring and consequent degraded operation of 
airplane systems.

DATES: We must receive comments on this proposed AD by November 15, 
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 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-2004-19203; the directorate identifier for this docket is 
2004-NM-109-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, [email protected].

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-2004-19203; 
Directorate Identifier 2004-NM-109-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

[[Page 58110]]

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

    During a certification review of a Boeing Model 737-700C series 
airplane, a frequency converter failure mode that was not identified in 
the original system design was found. This failure mode could cause a 
wiring short circuit between the frequency converter output and the 
distribution circuit breakers. The current is only limited by the 
maximum current capacity of the frequency converter. The frequency 
converter reacts to a short circuit condition by increasing the output 
current to approximately 54 amps, and significantly reducing the 
voltage. Investigation revealed that the wiring between the converter 
and the wiring fault was inadequate in size to handle the frequency 
converters increased output current. These conditions, if not 
corrected, could result in a short circuit between the frequency 
converter output and the distribution circuit breakers, which could 
result in overheating and failure of adjacent wiring and consequent 
degraded operation of airplane systems.
    The frequency converters on certain Model 757-200 series airplanes 
are identical to those on the affected Model 737-700C series airplane 
(the unsafe condition has been corrected on Model 737-700C series 
airplanes). Therefore, all of these models may be subject to the same 
unsafe condition.

Relevant Service Information

    We have reviewed Boeing Service Bulletin 757-25-0255, dated 
December 11, 2003. The service bulletin describes procedures for 
modifying the frequency converters located in the closet assembly in 
the passenger compartment. The modification involves installing new, 
improved frequency converters, relay assemblies, thermal switches, and 
related components, and making various wiring changes in and between 
the closet assembly and forward purser work station.
    Affected airplanes are separated into Groups 1 and 2, and the 
Accomplishment Instructions of the service bulletin provide 
modification procedures for each group, as follows: The procedures for 
Groups 1 and 2 include replacing three frequency converters in closet 
assembly S3 in the passenger compartment; installing three relay 
assemblies; and changing wire bundles in the P37 panel and forward 
purser work station, including at and above closet assembly S3. 
Additional procedures for Group 2 include changing wire bundle W3910 in 
the ceiling between closet assembly S3 and the forward purser work 
station. The procedures for Groups 1 and 2 also specify doing an 
operational test of the new/changed frequency converters and related 
circuit changes.
    Service Bulletin 757-25-0255 recommends prior or concurrent 
accomplishment of Boeing Service Bulletin 757-24-0093, dated August 14, 
2003. Service Bulletin 757-24-0093 describes procedures for modifying 
the in-flight entertainment system (circuit breaker, relays, and 
wiring). The modification procedures include installing a relay and 
changing the wiring in the main electronics compartment at the P37 
panel assembly; and installing a relay and changing the wiring in the 
P36 panel assembly. The procedures also specify doing a continuity 
test. The modification procedures are for airplanes listed in Group 1 
of Service Bulletin 757-24-0093.
    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 modifying the frequency converters located in the closet 
assembly in the passenger compartment, and making various wiring 
changes in and between the closet assembly and forward purser work 
station. This proposed AD also would require accomplishment of various 
other actions prior to or concurrently with the modification of the 
frequency converters. The proposed AD would require you to use the 
service information described previously to perform these actions.

Costs of Compliance

    This proposed AD would affect about 4 airplanes of U.S. registry 
and 4 airplanes worldwide.
    For airplanes listed in Group 1 of Service Bulletin 757-25-0255: 
The proposed modification would take about 97 work hours (including 
access, close-up, and test), at an average labor rate of $65 per work 
hour. Required parts would cost about $10,710 per airplane. Based on 
these figures, the estimated cost of the proposed modification for U.S. 
operators is $17,015 per airplane.
    For airplanes listed in Group 2 of Service Bulletin 757-25-0255: 
The proposed modification would take about 105 work hours (including 
access, close-up, and test), at an average labor rate of $65 per work 
hour. Required parts would cost about $10,956 per airplane. Based on 
these figures, the estimated cost of the proposed modification for U.S. 
operators is $17,781 per airplane.
    For airplanes listed in Group 1 of Service Bulletin 757-24-0093: 
The proposed concurrent modification, if not previously done, would 
take about 49 work hours, at an average labor rate of $65 per work 
hour. Required parts would cost about $5,315 per airplane. Based on 
these figures, the estimated cost of the proposed modification for U.S. 
operators is $8,500 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

[[Page 58111]]

    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.

Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

Boeing: Docket No. FAA-2004-19203; Directorate Identifier 2004-NM-
109-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by November 15, 2004.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Model 757-200 series airplanes, 
certificated in any category, as listed in Boeing Service Bulletin 
757-25-0255, dated December 11, 2003.

Unsafe Condition

    (d) This AD was prompted by a certification review that revealed 
a frequency converter failure mode not identified in the original 
system design. We are issuing this AD to prevent a short circuit 
between the frequency converter output and the distribution circuit 
breakers, which could result in overheating and failure of adjacent 
wiring and consequent degraded operation of airplane systems.

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 18 months after the effective date 
of this AD: Modify the frequency converters located in the closet 
assembly in the passenger compartment by doing all the applicable 
actions in accordance with the Accomplishment Instructions of Boeing 
Service Bulletin 757-25-0255, dated December 11, 2003.

Prior or Concurrent Modification

    (g) For Group 1 airplanes listed in Boeing Service Bulletin 757-
24-0093, dated August 14, 2003: Before or concurrent with 
accomplishment of paragraph (f) of this AD, Modify the in-flight 
entertainment system by doing all the applicable actions in 
accordance with Boeing Service Bulletin 757-24-0093, dated August 
14, 2003.

Part Installation

    (h) As of the effective date of this AD, no person may install a 
frequency converter having part number 1-002-0102-0730 on any 
airplane unless it has been modified as required by paragraph (f) of 
this AD.

Alternative Methods of Compliance (AMOCs)

    (i) 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 September 21, 2004.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-21818 Filed 9-28-04; 8:45 am]
BILLING CODE 4910-13-P
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