[Federal Register Volume 72, Number 220 (Thursday, November 15, 2007)]
[Rules and Regulations]
[Pages 64143-64145]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-22000]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-27740; Directorate Identifier 2006-NM-290-AD; 
Amendment 39-15256; AD 2007-23-10]
RIN 2120-AA64


Airworthiness Directives; Boeing 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 Boeing Model 737-600, -700, -700C, -800 and -900 series 
airplanes. This AD requires an inspection of the fillet sealant at the 
inboard and outboard sides of the receptacles in the wheel wells of the 
main landing gear, and related investigative/corrective actions if 
necessary. This AD results from reports of in-production airplanes with 
missing or insufficient fillet sealant around the receptacles at the 
disconnect bracket. We are issuing this AD to prevent corrosion damage 
due to missing or insufficient fillet sealant. Such corrosion could 
result in insufficient electrical bonding between the connectors and 
the disconnect bracket, and consequent loss of the shielding that 
protects the wire bundles from lightning, electromagnetic interference 
(EMI), and high intensity radiated field (HIRF). Loss of lightning, 
EMI, and HIRF protection at those receptacles could cause failure of 
multiple electrical systems and subsequent loss of several critical 
control systems that are necessary for safe flight. In addition, a 
lightning strike could cause arcing in the fuel tank; this potential 
ignition source, in combination with flammable fuel vapors, could 
result in a fuel tank explosion and consequent loss of the airplane.

DATES: This AD becomes effective December 20, 2007.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of December 20, 
2007.

ADDRESSES: For service information identified in this AD, contact 
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207.

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: Binh Tran, Aerospace Engineer, Systems 
and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton,

[[Page 64144]]

Washington 98057-3356; telephone (425) 917-6485; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov 
or in person at the Docket Operations office between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays. The Docket Operations 
office (telephone (800) 647-5527) is located on the ground floor of the 
West Building at the DOT street address stated in the ADDRESSES 
section.

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that would apply to certain Boeing Model 
737-600, -700, -700C, -800 and -900 series airplanes. That NPRM was 
published in the Federal Register on March 30, 2007 (72 FR 15073). That 
NPRM proposed to require an inspection of the fillet sealant at the 
inboard and outboard sides of the receptacles in the wheel wells of the 
main landing gear, and related investigative/corrective actions if 
necessary.

Comments

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

Support for NPRM

    Boeing and AirTran Airways support the NPRM's proposed actions.

Request for Parts Availability Accounting

    AirTran Airways requests that the expected parts usage and parts 
availability be reviewed and addressed for feasibility prior to the 
release of the final rule to ensure that parts shortages will not 
necessitate requests for unnecessary alternative means of compliance or 
adjustments of the compliance time. The commenter adds that there are 
36 part numbers that could possibly need replacement if there is 
corrosion beyond the acceptable limits in the service bulletin. Of 
these 36 connectors, 9 part numbers are not available; of those, 5 do 
not appear to be in the production pipeline. Quite a few part numbers 
show less than a dozen available.
    We agree with the request and have coordinated with Boeing 
regarding AirTran's concern. The NPRM cited Boeing Special Attention 
Service Bulletin 737-24-1169, dated December 15, 2006. Since we issued 
the NPRM, Boeing has revised the service bulletin. Revision 1, dated 
August 6, 2007, provides optional connector part numbers, which will 
ensure adequate replacement parts for the specified corrective actions. 
The remaining information in Revision 1 is essentially unchanged. We 
have revised paragraphs (c) and (f) of this final rule to refer to 
Revision 1 of the service bulletin as the appropriate source of service 
information for the applicability and the required actions. We have 
included credit for actions previously performed in accordance with the 
original service bulletin.

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.

Costs of Compliance

    There are about 333 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this AD.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                         Number of
                                                                Average      Cost per      U.S.-
                         Work hours                            labor rate    airplane    registered   Fleet cost
                                                                per hour                 airplanes
----------------------------------------------------------------------------------------------------------------
1...........................................................          $80          $80          118       $9,440
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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

0
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:


[[Page 64145]]


    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):

2007-23-10 Boeing: Amendment 39-15256. Docket No. FAA-2007-27740; 
Directorate Identifier 2006-NM-290-AD.

Effective Date

    (a) This AD becomes effective December 20, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 737-600, -700, -700C, -800 
and -900 series airplanes; certificated in any category; as 
identified in Boeing Special Attention Service Bulletin 737-24-1169, 
Revision 1, dated August 6, 2007.

Unsafe Condition

    (d) This AD results from reports of in-production airplanes with 
missing or insufficient fillet sealant around the receptacles 
installed in the wheel wells of the main landing gear (MLG). We are 
issuing this AD to prevent corrosion damage due to missing or 
insufficient fillet sealant. Such corrosion could result in 
insufficient electrical bonding between the connectors and the 
disconnect bracket, and consequent loss of the shielding that 
protects the wire bundles from lightning, electromagnetic 
interference (EMI), and high intensity radiated field (HIRF). Loss 
of lightning, EMI, and HIRF protection at those receptacles could 
cause failure of multiple electrical systems and subsequent loss of 
several critical control systems that are necessary for safe flight. 
In addition, a lightning strike could cause arcing in the fuel tank; 
this potential ignition source, in combination with flammable fuel 
vapors, could result in a fuel tank explosion and consequent loss of 
the airplane.

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.

Inspection

    (f) Within 24 months after the effective date of this AD, 
perform a detailed inspection to determine if there is sufficient 
fillet sealant at the inboard and outboard sides of the receptacles 
in the MLG wheel wells, in accordance with the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 737-24-
1169, Revision 1, dated August 6, 2007. Do all applicable related 
investigative and corrective actions before further flight in 
accordance with the service bulletin.
    (g) Accomplishment of an inspection and applicable related 
investigative and corrective actions done before the effective date 
of this AD in accordance with Boeing Special Attention Service 
Bulletin 737-24-1169, dated December 15, 2006, is considered 
acceptable for compliance with the corresponding requirements of 
paragraph (f) of this AD.

Alternative Methods of Compliance (AMOCs)

    (h)(1) 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.
    (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 appropriate principal inspector (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.

Material Incorporated by Reference

    (i) You must use Boeing Special Attention Service Bulletin 737-
24-1169, Revision 1, dated August 6, 2007, to perform the actions 
that are required by this AD, unless the AD specifies otherwise. The 
Director of the Federal Register approved the incorporation by 
reference of this document in accordance with 5 U.S.C. 552(a) and 1 
CFR part 51. Contact Boeing Commercial Airplanes, P.O. Box 3707, 
Seattle, Washington 98124-2207, for a copy of this service 
information. You may review copies at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue SW., Renton, Washington; or 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/cfr/ibr-locations.html.

    Issued in Renton, Washington, on November 2, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-22000 Filed 11-14-07; 8:45 am]
BILLING CODE 4910-13-P