FR Doc 04-25031

[Federal Register: November 10, 2004 (Volume 69, Number 217)]
[Proposed Rules]
[Page 65099-65101]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr10no04-19]

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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, 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-2004-19567;
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

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]

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