[Federal Register: December 1, 2010 (Volume 75, Number 230)]
[Rules and Regulations]
[Page 74616-74620]
[DOCID:fr01de10-4]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28348; Directorate Identifier 2007-NM-060-AD;
Amendment 39-16530; AD 2010-24-11]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Model 737-600, -700,
-700C, -800, and -900 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Model 737-600, -700, -700C, -800, and -900 series airplanes.
This AD requires sealing the fasteners on the front and

rear spars inside the main fuel tank and on the lower panel of the
center fuel tank, inspecting the wire bundle support installation in
the equipment cooling system bays to identify the type of clamp
installed and determine whether the Teflon sleeve is installed, and
doing related corrective actions if necessary. This AD results from a
design review of the fuel tank systems. We are issuing this AD to
prevent arcing at certain fuel tank fasteners in the event of a
lightning strike or fault current event, which, in combination with
flammable fuel vapors, could result in a fuel tank explosion and
consequent loss of the airplane.

DATES: This AD becomes effective January 5, 2011.
    The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in the AD as of January 5,
2011.

ADDRESSES: For service information identified in this AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax<PHONE_NUMBER>; e-mail<EMAIL_ADDRESS>
Internet https://www.myboeingfleet.com.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this AD, the regulatory evaluation,
any comments received, and other information. The address for the
Docket Office (telephone<PHONE_NUMBER>) is the Document Management
Facility, U.S. Department of Transportation, Docket Operations, M-30,
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE.,
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Tom Thorson, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone
(425) 917-6508; fax<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a second supplemental notice of proposed rulemaking
(NPRM) to amend 14 CFR part 39 to include an AD that would apply to
certain Model 737-600, -700, -700C, -800, and -900 series airplanes.
That second supplemental NPRM was published in the Federal Register on
March 23, 2009 (74 FR 12094). That second supplemental NPRM proposed to
require sealing the fasteners on the front and rear spars inside the
main fuel tank and on the lower panel of the center fuel tank,
inspecting the wire bundle support installation in the equipment
cooling system bays to identify the type of clamp installed and
determine whether the Teflon sleeve is installed, and doing related
corrective actions if necessary.

Relevant Service Information

    The second supplemental NPRM cited Boeing Alert Service Bulletin
737-57A1279, Revision 1, dated September 25, 2008, as the appropriate
source of service information. Boeing has since revised the service
bulletin. Boeing Service Bulletin 737-57A1279, Revision 2, dated
February 2, 2010, incorporates additional data that were included in
Boeing Information Notice (IN) 737-57A1279 IN 02, dated September 25,
2008; 737-57A1279 IN 03, dated October 30, 2008; and 737-57A1279 IN 04,
dated March 13, 2009. This additional information does not add more
work.
    Boeing has also issued IN 737-57A1279 IN 05, dated April 8, 2010.
This IN specifies that Model 737-800 and -900 airplanes may have an
additional clamp located at stringer 10 that requires the work shown in
the steps of Figures 6, 7, 10, and 11 of Boeing Service Bulletin 737-
57A1279, Revision 2, dated February 2, 2010, in the environmental
control system bay of the affected airplanes.

Comments

    We provided the public the opportunity to participate in the
development of this AD. We have considered the comments received on the
second supplemental NPRM.

Support for the Second Supplemental NPRM

    Boeing reviewed the second supplemental NPRM and concurred with the
contents of the proposed rule.

Request To Delay AD Action

    Continental Airlines (CAL) expressed continued concern that the
manufacturer needs to update the maintenance service documents to avoid
inadvertently demodifying the work that this AD requires, which would
result in potential enforcement action against CAL. CAL commented that
to ensure compliance with the maintenance planning data Fuel System
Airworthiness Limitations, the requirements of Appendix H.1(a) of the
Federal Aviation Regulations (14 CFR 25); and the requirements of
sections 26.1(a), 26.1(b)(2), and 26.1(b)(3) of the Federal Aviation
Regulations (14 CFR 26.1(a), 14 CFR 26.1(b)(2), and 14 CFR 26.1(b)(3));
must be complied with by the original equipment manufacturer or type
certificate holder. In addition, the operator must also comply with
section 91.1507(e) of the Federal Aviation Regulations (14 CFR
91.1507(e)); and section 121.1113(e) of the Federal Aviation
Regulations (14 CFR 121.1113(e)). CAL stated that these procedures
conflict with the regulations of sections 25.1529 and 25.1729 of the
Federal Aviation Regulations (14 CFR 25.1529 and 25.1729) and
applicable provisions of 14 CFR parts 21 and 26.
    We acknowledge the commenter's concern. However, no new ICAs have
been developed for the design change required by this AD. Operators and
owners are responsible for ensuring that the configuration mandated by
this AD is maintained in accordance with section 39.7 of the Federal
Aviation Regulations (14 CFR 39.7).
    If any new airworthiness limitations (AWLs) related to any of the
design features mandated by this AD are developed, we may consider
additional rulemaking to mandate incorporations of those AWLs into
operators' maintenance programs. We have not changed the AD in regard
to this issue.
    CAL cited sections 91.1507(e) of the Federal Aviation Regulations
(14 CFR 91.1507(e)) and other regulations and expresses concern that
the absence of the ICAs could result in enforcement action. That
section requires operators to include in their maintenance programs all
fuel system ICAs developed under Special Federal Aviation Regulation
(SFAR) 88. However, that regulation requires operators to incorporate
ICAs provided by the design approval holder. Since no ICAs were
developed for the required modification, operators do not violate that
regulation if their maintenance programs do not yet contain ICAs for
the referenced design change. However, under section 39.7 of the
Federal Aviation Regulations (14 CFR 39.7), it is still the
responsibility of the operators to keep their airplanes in a
configuration that is in compliance with the AD. We have not changed
the AD in regard to this issue.
    The FAA is working with industry to evaluate potential changes to
the AD process that are intended to more clearly identify how to
maintain configurations that are required for AD compliance.

Request To Clarify Airplanes Subject to Paragraph (i) of the AD

    The Air Transport Association (ATA), on behalf of its member
American Airlines (AA), requested that we clarify the ``applicability
requirements'' in paragraph (i) of the second supplemental NPRM to
state that modifications should be acceptable for compliance with the
AD if they were made in accordance with Boeing Alert Service Bulletin
737-57A1279, dated January 24, 2007, and if the table in paragraph
1.A., ``Effectivity,'' of that service bulletin was used to correctly
determine which airplanes are subject to the requirements of paragraph
(i) of the AD. The commenter noted that the variable numbers following
the table are erroneous.
    Lufthansa Technik (LTK) also requested that we revise paragraph (i)
of the second supplemental NPRM. LTK requested that we consider
airplanes with line numbers 571 through 1691 inclusive on which the
referenced actions have been performed in accordance with Boeing Alert
Service Bulletin 737-57A1279, dated January 24, 2007, to be compliant
with the proposed AD.
    We agree with the requests to clarify which airplanes are subject
to the requirements of paragraph (i) of this final rule. We have
revised paragraph (i) of this final rule to state that actions done
using the group assignments by line numbers found in the table in
paragraph 1.A., ``Effectivity,'' and in accordance with the original
service bulletin, Boeing Service Bulletin 737-57A1279, dated January
24, 2007, are acceptable for compliance with the corresponding
requirements of this AD.

Request To Allow Alternative Teflon Sleeving Procedure

    The ATA, on behalf of its member AA, proposed an alternative
sleeving procedure. In its comment, AA stated that the Teflon sleeve
installation cannot be accomplished as shown in Figure 13 of Boeing
Alert Service Bulletin 737-57A1279, dated January 24, 2007. AA stated
that Figure 9 of the service bulletin shows that the adjacent tube
conduit does not allow the sleeve to be 3 inches long and centered on
the clamp. AA proposed that an alternative sleeving procedure extend
the sleeving at least 1 inch beyond the edge of the clamp. If 1 inch of
sleeving cannot be achieved, AA suggested that the sleeving be extended
as far as possible.
    We agree that clarification may be necessary. Boeing is revising
Boeing Alert Service Bulletin 737-57A1279 to address this issue.
However, due to the urgency of the unsafe condition and in
consideration of the amount of time that has already elapsed since
issuance of the original service bulletin, we have determined that
further delay of this final rule is not appropriate. We disagree with
the request to allow an alternative Teflon sleeving procedure in this
final rule. We do not have sufficient data that indicate this procedure
provides an acceptable level of safety. If operators can provide
sufficient data to indicate that an alternative Teflon sleeving
procedure would provide an acceptable level of safety, operators can
request approvals of AMOCs in accordance with the requirements of
paragraph (j) of this final rule. We have not changed the final rule
regarding this issue.

Request To Allow Alternative Procedure To Seal Fasteners on Wing and
Main Tanks

    The ATA, on behalf of its member AA, requested that we remove the
proposed requirement to reseal the fasteners if already done previously
in accordance with Boeing Alert Service Bulletin 737-57A1279, dated
January 24, 2007. In its comment, AA stated that sealant has been
previously applied at some fastener locations in the center tank and
the wing tanks during airplane assembly. Therefore, AA stated, it is
not possible to accomplish the steps in Figures 14 and 15 of that
service bulletin, and AA proposed that if the fasteners are sealed in
accordance with that service bulletin, then no further work should be
required. AA also stated that Boeing 737-57A1279 Information Notice
(IN) 04, dated March 13, 2009, addresses this issue.
    We agree with the commenter. Boeing 737-57A1279 IN 04, dated March
13, 2009, states that for fasteners that have been previously sealed to
the specifications of Boeing Alert Service Bulletin 737-57A1279, it is
not required for the existing seal to be removed and the fastener
sealed again. Boeing Service Bulletin 737-57A1279, Revision 2, dated
February 2, 2010, incorporates the information included in Boeing 737-
57A1279 IN 04, dated March 13, 2009. We updated this final rule to
refer to Boeing Alert Service Bulletin 737-57A1279, Revision 2, dated
February 2, 2010, as an appropriate source of service information.

Request To Reference Additional Service Information

    The ATA, on behalf of its member AirTran Airways, requested that we
approve Boeing Information Notices 03 and 04 as sources of service
information for the supplemental NPRM. In its comment, AirTran Airways
stated that the information notices clarify and provide corrections to
Boeing Service Bulletin 737-57A1279, Revision 1, dated September 25,
2008.
    We partially agree. We acknowledge that the information contained
in these notices may be useful to operators to complete the
requirements of this AD. However, Boeing has issued Boeing Service
Bulletin 737-57A1279, Revision 2, dated February 2, 2010, to include
the information in the information notices. We have revised the final
rule accordingly.

Explanation of Change Made to This AD

    We have revised this AD to identify the legal name of the
manufacturer as published in the most recent type certificate data
sheet for the affected airplane models.

Conclusion

    We have carefully reviewed the available data, including the
comments received, and determined that air safety and the public
interest require adopting the AD with the changes described previously.
We have determined that these changes will neither increase the
economic burden on any operator nor increase the scope of the AD.

Explanation of Change to Costs of Compliance

    Since issuance of the NPRM, we have increased the labor rate used
in the Costs of Compliance from $80 per work-hour to $85 per work-hour.
The Costs of Compliance information, below, reflects this increase in
the specified hourly labor rate.

Costs of Compliance

    There are about 1,754 airplanes of the affected design in the
worldwide fleet; of these, 645 airplanes are U.S.-registered. The
following table provides the estimated costs for U.S. operators to
comply with this final rule, at an average hourly labor rate of $85.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                Number of U.S.-
                    Action                       Group       Work      Cost per      registered     Fleet cost
                                                            hours      airplane      airplanes
----------------------------------------------------------------------------------------------------------------
Sealant application..........................          1         62       $5,270             586      $3,088,220
                                                       2         28       $2,380              44         104,720
                                                       3         28       $2,380              15          35,700
Inspection...................................          1          4         $340             586         199,240
                                                       2          4         $340              44          14,960
                                                       3          2         $170              15           2,550
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. 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.
    We are issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701, ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe 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
rulemaking action.

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 this AD:
    (1) Is not a ``significant regulatory action'' under Executive
Order 12866;
    (2) Is not a ``significant rule'' under 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 AD and placed it in the AD docket. 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, Incorporation by
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The Federal Aviation Administration (FAA) amends Sec.  39.13 by
adding the following new airworthiness directive (AD):

2010-24-11 The Boeing Company: Amendment 39-16530. Docket No. FAA-
2007-28348; Directorate Identifier 2007-NM-060-AD.

Effective Date

    (a) This AD becomes effective January 5, 2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to The Boeing Company Model 737-600, -700, -
700C, -800, and -900 series airplanes, certificated in any category;
as identified in Boeing Service Bulletin 737-57A1279, Revision 2,
dated February 2, 2010.

Subject

    (d) Air Transport Association (ATA) of America Code 57: Wings.

Unsafe Condition

    (e) This AD results from a design review of the fuel tank
systems. The Federal Aviation Administration is issuing this AD to
prevent arcing at certain fuel tank fasteners in the event of a
lightning strike or fault current event, which, in combination with
flammable fuel vapors, could result in a fuel tank explosion and
consequent loss of the airplane.

Compliance

    (f) You are responsible for having the actions required by this
AD performed within the compliance times specified, unless the
actions have already been done.

Fastener Sealant

    (g) Within 60 months after the effective date of this AD: Seal
the fasteners on the front and rear spars inside the main fuel tank
and on the lower panel of the center fuel tank, as applicable, in
accordance with the Accomplishment Instructions of Boeing Service
Bulletin 737-57A1279, Revision 2, dated February 2, 2010.

Inspection and Corrective Action

    (h) Within 60 months after the effective date of this AD:
Perform a general visual inspection of the wire bundle support
installation in the equipment cooling system bays to identify the
type of clamp installed, and determine whether the Teflon sleeve is
installed. Do these actions in accordance with the Accomplishment
Instructions of Boeing Service Bulletin 737-57A1279, Revision 2,
dated February 2, 2010. Do all applicable corrective actions before
further flight in accordance with the Accomplishment Instructions of
Boeing Service Bulletin 737-57A1279, Revision 2, dated February 2,
2010. Certain Model 737-800 and 737-900 airplanes may have an
additional clamp location at stringer 10 that is required to perform
the steps of Figures 6, 7, 10, and 11 of Boeing Service Bulletin
737-57A1279, Revision 2, dated February 2, 2010, in the
environmental control systems (ECS) bay.

Actions Accomplished Previously

    (i) Actions done before the effective date of this AD using the
group assignments with the line numbers in the table in paragraph
1.A., ``Effectivity,'' and in accordance with Boeing Alert Service
Bulletin 737-57A1279, dated January 24, 2007; or Revision 1, dated
September 25, 2008; are acceptable for compliance with the
corresponding requirements of this AD.

Alternative Methods of Compliance (AMOCs)

    (j)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, has the authority to approve AMOCs for this AD, if requested
using the procedures found in 14 CFR 39.19. Send information to
ATTN: Tom Thorson, Aerospace Engineer, Propulsion Branch, ANM-140S,
FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW.,

Renton, Washington 98057-3356; telephone<PHONE_NUMBER>; fax (425)
917-6508. Or, e-mail information to 9-ANM-Seattle-ACO-AMOC-
<EMAIL_ADDRESS>    (2) To request a different method of compliance or a different
compliance time for this AD, follow the procedures in 14 CFR 39.19.
Before using any approved AMOC on any airplane to which the AMOC
applies, notify your principal maintenance inspector (PMI) or
principal avionics inspector (PAI), as appropriate, or lacking a
principal inspector, your local Flight Standards District Office.
The AMOC approval letter must specifically reference this AD.

Material Incorporated by Reference

    (k) You must use Boeing Service Bulletin 737-57A1279, Revision
2, dated February 2, 2010, to do the actions required by this AD,
unless the AD specifies otherwise.
    (1) The Director of the Federal Register approved the
incorporation by reference of this service information under 5
U.S.C. 552(a) and 1 CFR part 51.
    (2) For service information identified in this AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone
206-544-5000, extension 1; fax<PHONE_NUMBER>; e-mail
<EMAIL_ADDRESS>Internet https://www.myboeingfleet.com.
    (3) You may review copies of the service information at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington. For information on the availability of this material at
the FAA, call<PHONE_NUMBER>.
    (4) You may also review copies of the service information that
is incorporated by reference at the National Archives and Records
Administration (NARA). For information on the availability of this
material at NARA, call<PHONE_NUMBER>, or go to: http://
www.archives.gov/federal_register/code_of_federal_regulations/
ibr_locations.html.

    Issued in Renton, Washington on November 18, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2010-29792 Filed 11-30-10; 8:45 am]
BILLING CODE 4910-13-P