Document ID: FAA-2007-28348-0018
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Boeing Co. Model 737-600, -700, -700C, -800, and -900 Series Airplanes
Posted Date: 2010-12-01T05:00Z

[Federal Register: December 1, 2010 (Volume 75, Number 230)]
[Rules and Regulations]               
[Page 74616-74620]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr01de10-4]                         

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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.

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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

[[Page 74617]]

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 206-766-5680; e-mail me.boecom@boeing.com; 
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 800-647-5527) 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 (425) 917-6590.

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.

[[Page 74618]]

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.

[[Page 74619]]

                                                 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.,

[[Page 74620]]

Renton, Washington 98057-3356; telephone (425) 917-6510; fax (425) 
917-6508. Or, e-mail information to 9-ANM-Seattle-ACO-AMOC-
Requests@faa.gov.
    (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 206-766-5680; e-mail 
me.boecom@boeing.com; 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 425-227-1221.
    (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 202-741-6030, 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]
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