Document ID: FAA-2007-0202-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Boeing Model 737-600, 737-700, 737- 700C, 737-800, and 737-900 Series Airplanes
Posted Date: 2007-11-19T05:00Z

[Federal Register: November 19, 2007 (Volume 72, Number 222)]
[Proposed Rules]               
[Page 64955-64957]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19no07-14]                         

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Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

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[[Page 64955]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-0202; Directorate Identifier 2007-NM-185-AD]
RIN 2120-AA64

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

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (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 737-600, 737-700, 737-700C, 737-800, and 737-
900 series airplanes. This proposed AD would require an inspection of 
the vertical fin lugs, skin, and skin edges for discrepancies, an 
inspection of the flight control cables, fittings, and pulleys in 
section 48 for signs of corrosion, an inspection of the horizontal 
stabilizer jackscrew, ball nut, and gimbal pins for signs of corrosion, 
and corrective actions if necessary. This proposed AD results from 
reports indicating that moisture was found within the section 48 
cavity. We are proposing this AD to ensure that the correct amount of 
sealant was applied around the vertical fin lugs, skin and the skin 
edges. Missing sealant could result in icing of the elevator cables, 
which could cause a system jam and corrosion of structural and flight 
control parts, resulting in reduced controllability of the airplane.

DATES: We must receive comments on this proposed AD by January 3, 2008.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    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 proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Office (telephone 800-647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Wayne Lockett, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6447; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2007-0202; 
Directorate Identifier 2007-NM-185-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://
www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    We have received reports indicating that moisture was found within 
the section 48 cavity on Boeing Model 737-600, 737-700, 737-700C, 737-
800, and 737-900 series airplanes. A root-cause investigation 
determined that, due to a manufacturing process error, airplanes were 
delivered with an incorrect amount of sealant around the station (STA) 
1088 vertical fin lugs common to the section 48 skin. This condition, 
if not corrected, could result in icing of the elevator cables, which 
could cause a system jam and corrosion of structural and flight control 
parts, resulting in reduced controllability of the airplane.

Relevant Service Information

    We have reviewed Boeing Service Bulletin 737-53A1242, Revision 2, 
dated April 23, 2007. The service bulletin describes the following 
procedures:
     Inspecting the vertical fin lugs, skin, and skin edges for 
discrepancies (i.e. water ingress, corrosion damage, and missing, 
insufficient, or cracked sealant).
     Performing a detailed inspection of the flight control 
cables, fittings, and pulleys in section 48 for signs of corrosion.
     Performing a detailed inspection of the horizontal 
stabilizer jackscrew, ball nut, and gimbal pins for signs of corrosion.
     Performing applicable corrective actions. The corrective 
actions include repairing cracks, filling the space between the 
vertical fin lugs and skin, lubricating the horizontal stabilizer trim 
actuator and actuator gimbal pins, replacing any cracked sealant with a 
new sealant, and contacting Boeing for corrosion repair conditions, as 
applicable.
    Accomplishing the actions specified in the service information 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. For this reason, we are proposing this AD, 
which would require accomplishing the actions specified in the service 
information described

[[Page 64956]]

previously, except as discussed under ``Difference Between the Proposed 
AD and Service Bulletin.''

Difference Between the Proposed AD and Service Bulletin

    In this proposed AD, the ``inspection'' and ``visual inspection'' 
specified in the Boeing service bulletin 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 bulletin specifies to contact the manufacturer for 
instructions on how to repair certain conditions, but this proposed AD 
would require repairing those conditions in one of the following ways:
     Using a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by an Authorized Representative 
for the Boeing Commercial Airplanes Delegation Option Authorization 
Organization whom we have authorized to make those findings.

Costs of Compliance

    There are about 829 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 372 airplanes of 
U.S. registry. The proposed actions would take about 1 work hour per 
airplane, at an average labor rate of $80 per work hour. Based on these 
figures, the estimated cost of the proposed AD for U.S. operators is 
$29,760, or $80 per airplane.

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

Boeing: Docket No. FAA-2007-0202; Directorate Identifier 2007-NM-
185-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by January 
3, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to certain Boeing Model 737-600, 737-700, 
737-700C, 737-800, and 737-900 series airplanes, certificated in any 
category; as identified in Boeing Service Bulletin 737-53A1242, 
Revision 2, dated April 23, 2007.

Unsafe Condition

    (d) This AD results from reports indicating that moisture was 
found within the section 48 cavity. We are issuing this AD to ensure 
that the correct amount of sealant was applied around the vertical 
fin lugs, skin and the skin edges. Missing sealant could result in 
icing of the elevator cables, which could cause a system jam and 
corrosion of structural and flight control parts, resulting in 
reduced controllability 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.

Inspections

    (f) Within 2,500 flight cycles or 18 months after the effective 
date of this AD, whichever occurs first, do the detailed inspections 
specified in paragraphs (f)(1), (f)(2) and (f)(3) of this AD in 
accordance with the Accomplishment Instructions of the Boeing 
Service Bulletin 737-53A1242, Revision 2, dated April 23, 2007.
    (1) Do a detailed inspection of the vertical fin lugs, skin, and 
skin edges for discrepancies (i.e. water ingress, corrosion damage, 
and missing, insufficient, or cracked sealant).
    (2) Do a detailed inspection of the flight control cables, 
fittings, and pulleys in section 48 for signs of corrosion.
    (3) Do a detailed inspection of the horizontal stabilizer 
jackscrew, ball nut, and gimbal pins for signs of corrosion.

    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 (i.e., the person performing the inspection). 
Inspection aids such as mirror, magnifying lenses, etc., may be 
used. Surface cleaning and elaborate access procedures may be 
required.''

Corrective Actions

    (g) If any discrepancy or corrosion is found during any 
inspection required by paragraph (f) of this AD, before further 
flight, do the applicable corrective actions in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 737-53A1242, 
Revision 2, dated April 23, 2007; except where the service bulletin 
specifies to contact Boeing, repair using a method approved in 
accordance with the procedures specified in paragraph (i) of this 
AD.

Credit for Actions Done Using the Previous Service Information

    (h) Actions accomplished before the effective date of this AD in 
accordance with Boeing Service Bulletin 737-53A1242, dated October 
17, 2002; and Revision 1, dated April 28, 2005; are considered 
acceptable for compliance with the corresponding actions specified 
in paragraphs (f) and (g) of this AD.

Alternative Methods of Compliance (AMOCs)

    (i)(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.

[[Page 64957]]

    (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.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, Seattle ACO, to make those findings. For a repair 
method to be approved, the repair must meet the certification basis 
of the airplane, and the approval must specifically refer to this 
AD.

    Issued in Renton, Washington, on November 7, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-22548 Filed 11-16-07; 8:45 am]

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