[Federal Register Volume 69, Number 217 (Wednesday, November 10, 2004)]
[Proposed Rules]
[Pages 65099-65101]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-25031]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-19567; Directorate Identifier 2004-NM-118-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-200, -200C, -300, -
400, -500, -600, -700, -700C, -800, and -900 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 737-200, -200C, -300, -400, -500, -600, -700, 
-700C, -800, and -900 series airplanes. This proposed AD would require 
a one-time detailed inspection for discrepancies of the secondary fuel 
vapor barrier of the wing center section, and related investigative/
corrective actions if necessary. This proposed AD is prompted by 
reports that the secondary fuel vapor barrier was not applied correctly 
to, or was missing from, certain areas of the wing center section. We 
are proposing this AD to prevent fuel or fuel vapors from leaking into 
the cargo or passenger compartments and coming into contact with a 
possible ignition source, which could result in fire or explosion.

DATES: We must receive comments on this proposed AD by December 27, 
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.
    You can get the service information identified in this proposed AD 
from Boeing Commercial Airplanes, PO 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.

FOR FURTHER INFORMATION CONTACT: Technical information: Doug Pegors, 
Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6504; 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 relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2004-19567; 
Directorate Identifier 2004-NM-118-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

[[Page 65100]]

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 in person at the Docket Management 
Facility office between 9:00 a.m. and 5:00 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 manufacture, the 
secondary fuel vapor barrier was not applied correctly to the wing 
center section front spar and upper panel of certain Boeing Model 737-
300 series airplanes. The vapor barrier was also not applied 
continuously along the front spar vertical stiffeners and the top panel 
floor beams. In addition, inspections of Boeing Model 737-600, -700, 
and -800 series airplanes revealed these same conditions. The secondary 
fuel vapor barrier was also missing from the side body corner of the 
spar upper panel of the wing center section and the lower row of 
fasteners on the front spar. The vapor barrier on these airplanes also 
was too thin in some areas and too thick in other areas of the top 
panel and front spar. This condition, if not corrected, could result in 
fuel or fuel vapors leaking through fasteners or cracks in the wing 
center section into the cargo or passenger compartments and coming into 
contact with a possible ignition source, which could result in fire or 
explosion.
    The vapor barrier installations on Boeing Model 737-300 series 
airplanes are identical to those on Model 737-200, -200C, -400, and -
500 series airplanes, and the vapor barrier installations on Model 737-
600, -700, and -800 series airplanes are identical to those on Model 
737-700C, and -900 series airplanes. Therefore, all of these models may 
be subject to the identified unsafe condition.

Relevant Service Information

    We have reviewed Boeing Special Attention Service Bulletin 737-57-
1261, dated February 27, 2003; and Boeing Special Attention Service 
Bulletin 737-57-1250, Revision 1, dated September 4, 2003. The service 
bulletins describe procedures for a one-time detailed visual inspection 
for discrepancies of the secondary fuel vapor barrier of the front spar 
and top panel of the wing center section; and related investigative/
corrective actions, if necessary. Discrepancies include areas of the 
secondary fuel vapor barrier that are missing, peeling, non-
transparent, non-continuous, too thin, or too thick. Investigative 
action includes measuring the thickness of the secondary fuel vapor 
barrier with a non-conductive coating thickness gauge. Corrective 
actions include removing incorrectly applied secondary fuel vapor 
barrier, primers, sealants, corrosion inhibitors, and embedded metallic 
particles; and applying new primers, sealants, corrosion inhibitors, 
filleting seals, and secondary fuel vapor barrier; as necessary.
    Accomplishing the actions specified in the service bulletins 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 to 
require a one-time detailed inspection for discrepancies of the 
secondary fuel vapor barrier of the wing center section, and related 
investigative/corrective actions if necessary. The proposed AD would 
require you to use the service information described previously to 
perform these actions except as specified under ``Clarification of 
Inspection Terminology.''

Clarification of Inspection Terminology

    In this proposed AD, the ``detailed visual inspection'' specified 
in the service bulletins is referred to as a ``detailed inspection.'' 
We have included the definition for a detailed inspection in a note in 
the proposed AD.
    The service bulletins refer to a ``special detailed inspection'; 
however, this action is actually a measurement of the thickness of the 
secondary fuel vapor barrier using a non-conductive coating thickness 
gauge. The proposed AD would refer to this measurement of the secondary 
fuel vapor barrier as ``related investigative action'' rather than a 
special detailed inspection.

Costs of Compliance

    This proposed AD would affect about 1,521 airplanes of U.S. 
registry and 3,861 airplanes worldwide. We estimate the average labor 
rate to be $65 per work hour. We estimate that it would take the number 
of work hours shown in the following table to accomplish the proposed 
actions for each airplane. Parts and materials are standard and are to 
be supplied by the operator. Based on these figures, the cost impact of 
the proposed AD is estimated to range between $325 and $910 per 
airplane.

                          Estimated Work Hours
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                                                        Airplane   Work
          Affected  airplanes  as listed in              group     hours
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Boeing Special Attention Service Bulletin 737-57-              1      14
 1250, Revision 1, dated September 4, 2003...........          2      12
                                                               3       5
Boeing Special Attention Service Bulletin 737-57-              1      14
 1261, dated February 27, 2003.......................          2       7
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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:

[[Page 65101]]

    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.


Sec.  39.13  [Amended]

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

Boeing: Docket No. FAA-2004-19567; Directorate Identifier 2004-NM-
118-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by December 27, 2004.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to the airplanes listed in Table 1 of this 
AD, certificated in any category:

                                             Table 1.--Applicability
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             Model                                                 Line numbers
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737-200, -200C, -300, -400, and  311 through 3132 inclusive.
 -500 series airplanes.
737-600, -700, -700C, -800, and  1 through 1088 inclusive and 1090 through 1134 inclusive.
 -900 series airplanes.
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Unsafe Condition

    (d) This AD is prompted by reports that the secondary fuel vapor 
barrier was not applied correctly to, or was missing from, certain 
areas of the wing center section. We are issuing this AD to prevent 
fuel or fuel vapors from leaking into the cargo or passenger 
compartments and coming into contact with a possible ignition 
source, which could result in fire or explosion.

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.

Service Bulletin References

    (f) The term ``service bulletin,'' as used in this AD, means the 
Accomplishment Instructions of the following service bulletins, as 
applicable:
    (1) For Model 737-200, -200C, -300, -400, and -500 series 
airplanes: Boeing Special Attention Service Bulletin 737-57-1261, 
dated February 27, 2003; and
    (2) For Model 737-600, -700, -700C, -800, and -900 series 
airplanes: Boeing Special Attention Service Bulletin 737-57-1250, 
Revision 1, dated September 4, 2003.

Inspection

    (g) Within 48 months after the effective date of this AD, do a 
one-time detailed inspection for discrepancies of the secondary fuel 
vapor barrier of the wing center section; and if discrepancies 
exist, before further flight, do any applicable related 
investigative/corrective actions in accordance with the 
Accomplishment Instructions of the applicable service bulletin.

    Note 1: For the purposes of this AD, a detailed inspection is: 
``An intensive visual examination of a specific structural area, 
system, installation, or assembly to detect damage, failure, or 
irregularity. Available lighting is normally supplemented with a 
direct source of good lighting at intensity deemed appropriate by 
the inspector. Inspection aids such as mirror, magnifying lenses, 
etc., may be used. Surface cleaning and elaborate access procedures 
may be required.''

Actions Accomplished per Previous Issue of Service Bulletin

    (h) Actions accomplished before the effective date of this AD in 
accordance with Boeing Special Attention Service Bulletin 737-57-
1250, dated February 7, 2002, are considered acceptable for 
compliance with the corresponding actions specified in paragraph (g) 
of this AD.

Alternative Methods of Compliance (AMOCs)

    (i) The Manager, Seattle Aircraft Certification Office (ACO), 
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 November 1, 2004.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-25031 Filed 11-9-04; 8:45 am]
BILLING CODE 4910-13-P