[Federal Register Volume 75, Number 6 (Monday, January 11, 2010)]
[Proposed Rules]
[Pages 1297-1301]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-187]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-1253; Directorate Identifier 2009-NM-080-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, -900, and -900ER 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 supersede an existing airworthiness 
directive (AD) that applies to all Boeing Model 737-600, -700, -700C, -
800, -900, and -900ER series airplanes. The existing AD currently 
requires repetitive detailed inspections of the slat track downstop 
assemblies to verify that proper hardware is installed, one-time 
torquing of the nut and bolt, and corrective actions if necessary. This 
proposed AD would also require replacing the hardware of the down stop 
assembly with new hardware of the down stop assembly, doing a detailed 
inspection or a borescope inspection of the slat cans on each wing and 
the lower rail of the slat main tracks for debris, replacing the bolts 
of the aft side guide with new bolts, and removing any debris found in 
the slat can. This proposed AD also would remove airplanes from the 
applicability. This proposed AD results from reports of parts coming 
off the main slat track downstop assemblies. We are proposing this AD 
to prevent loose or missing parts from the main slat track downstop 
assemblies from falling into the slat can and causing a puncture, which 
could result in a fuel leak and consequent fire.

DATES: We must receive comments on this proposed AD by February 25, 
2010.

[[Page 1298]]


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 proposed 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 [email protected]; 
Internet https://www.myboeingfleet.com. You may review copies of the 
referenced 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 or 
425-227-1152.

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: Nancy Marsh, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6440; 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-2009-1253; 
Directorate Identifier 2009-NM-080-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

    On August 28, 2007, we issued AD 2007-18-52, amendment 39-15197 (72 
FR 53928, September 21, 2007), for all Boeing Model 737-600, -700, -
700C, -800, -900, and -900ER series airplanes. That AD superseded 
emergency AD 2007-18-51 to require a shorter compliance time for the 
actions originally required in emergency AD 2007-18-51. AD 2007-18-52 
requires repetitive detailed inspections of the slat track downstop 
assemblies to verify that proper hardware is installed, one-time 
torquing of the nut and bolt, and corrective actions if necessary. That 
AD resulted from reports of parts coming off the main slat track 
downstop assemblies. We issued that AD to detect and correct loose or 
missing parts from the main slat track downstop assemblies from falling 
into the slat can and causing a puncture, which could result in a fuel 
leak and consequent fire.

Actions Since Existing AD Was Issued

    The preamble to AD 2007-18-52 explains that we consider the 
requirements ``interim action'' and were considering further 
rulemaking. Since we issued AD 2007-18-52, Boeing has modified the 
hardware of the down stop assembly and the bolts of the aft side guide. 
The new modifications would terminate the actions required in AD 2007-
18-52. We now have determined that further rulemaking is indeed 
necessary, and this proposed AD follows from that determination.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 737-57A1302, dated 
December 15, 2008. The service bulletin describes procedures for 
replacing the hardware of the down stop assembly with new hardware, 
doing a detailed inspection or a borescope inspection of the slat cans 
on each wing and the lower rail of the slat main tracks for debris, 
replacing the bolts of the aft side guide with new bolts, and removing 
any debris found in the slat can.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to develop on other airplanes of the 
same type design. For this reason, we are proposing this AD, which 
would supersede AD 2007-18-52 and would retain the requirements of the 
existing AD. This proposed AD would also require accomplishing the 
actions specified in the Relevant Service Information described 
previously. The proposed AD would also remove certain airplanes having 
line numbers 2700 and on from the applicability; these airplanes have a 
design change incorporated during production, which is an equivalent 
change to the actions described in the Relevant Service Information.

Change to Existing AD

    This proposed AD would retain all requirements of AD 2007-18-52. As 
a result, the corresponding paragraph identifiers have changed in this 
proposed AD, as listed in the following table:

                      Revised Paragraph Identifiers
------------------------------------------------------------------------
                                             Corresponding  requirement
       Requirement in AD 2007-18-52             in this  proposed AD
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paragraph (f).............................  paragraph (g).
paragraph (g).............................  paragraph (h).
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Costs of Compliance

    There are about 2,699 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

[[Page 1299]]



                                                                     Estimated Costs
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                                                                                                                  Number of
                                                        Average labor                                               U.S.-
                 Action                    Work hours   rate per hour     Parts          Cost per airplane        registered          Fleet cost
                                                                                                                  airplanes
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Inspection and Torquing (required by AD             8             $80           $0  $640, per inspection cycle.          853  $545,920, per inspection
 2007-18-52).                                                                                                                  cycle.
Inspection and Modification (new                   18              80        5,388  6,828......................          853  5,824,284.
 proposed actions).
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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 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, Incorporation by 
reference, 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 removing amendment 39-15197 (72 FR 
53928, September 21, 2007) and adding the following new AD:

Boeing: Docket No. FAA-2009-+++++; Directorate Identifier 2009-NM-
080-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by February 
25, 2010.

Affected ADs

    (b) This AD supersedes AD 2007-18-52.

Applicability

    (c) This AD applies to Boeing Model 737-600, -700, -700C, -800, 
-900, and -900ER series airplanes, certificated in any category, as 
identified in Boeing Alert Service Bulletin 737-57A1302, dated 
December 15, 2008.

Subject

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

Unsafe Condition

    (e) This AD results from reports of parts coming off the main 
slat track downstop assemblies. The Federal Aviation Administration 
is issuing this AD to prevent loose or missing parts from the main 
slat track downstop assemblies from falling into the slat can and 
causing a puncture, which could result in a fuel leak and consequent 
fire.

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.

Restatement of AD 2007-18-52 With No Changes

    Note 1:  Paragraph (g) of this AD merely restates the 
requirements of paragraph (f)(1) of emergency AD 2007-18-51 (which 
was superseded by AD 2007-18-52). As allowed by the phrase, ``unless 
the actions have already been done,'' if the applicable initial 
inspections required by paragraph (f)(1) of emergency AD 2007-18-51 
have already been done, this AD does not require that those 
inspections be repeated until the repetitive interval of 3,000 
flight cycles.

Repetitive Detailed Inspections

    (g) Within 10 days after September 26, 2007 (the effective date 
of AD 2007-18-52): Do a detailed inspection or a borescope 
inspection of each main slat track downstop assembly to verify 
proper installation of the slat track hardware (i.e., the bolt, 
washers, downstops, stop location, and nut shown in Figure 1 of 
Boeing Service Letter 737-SL-57-084-B, dated July 10, 2007, and in 
this AD). Proper installation of the sleeve need not be confirmed, 
and the stop location part may be installed on either the inboard or 
the outboard side of the slat track. If any part is missing or is 
installed improperly, before further flight, install a new or 
serviceable part using a method approved in accordance with the 
procedures specified in paragraph (j) of this AD; and do a detailed 
inspection of the inside of the slat can for foreign object debris 
(FOD) and damage. Before further flight, remove any FOD found and 
repair any damage found using a method approved in accordance with 
the procedures specified in paragraph (j) of this AD. Verify proper 
installation; install a new or serviceable part; and inspect for 
damage and FOD, and remove FOD and repair damage, in accordance with 
a method by approved by the Manager, Seattle Aircraft Certification 
Office, FAA; or in accordance with Boeing Multi Operator Message 
Number 1-523812011-1, issued August 25, 2007; or 1-527463441-1, 
issued August 28, 2007. Repeat the actions required by paragraph (g) 
of this AD thereafter at intervals not to exceed 3,000 flight 
cycles.

    Note 2:  Paragraph (h) of this AD merely restates the 
requirements of paragraph (f)(2) of emergency AD 2007-18-51. As 
allowed by the phrase, ``unless the actions have already been 
done,'' if the torque application required by paragraph (f)(2) of AD 
emergency 2007-18-51 has already been done, this AD does not require 
that the torque application be repeated.


[[Page 1300]]



One-Time Torquing

    (h) Within 24 days after receipt of emergency AD 2007-18-51: 
Apply a torque between 50 to 80 inch-pounds to the nut. The bolt 
head must be held with the torque applied to the nut.

    Note 3:  For the purposes of this AD, a detailed inspection is: 
``An intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirror, magnifying lenses, etc., may be necessary. Surface cleaning 
and elaborate procedures may be required.''

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New Requirements of This AD

Modification and Inspection

    (i) Within 36 months after the effective date of this AD: 
Replace the hardware of the down stop assembly with new hardware, do 
a detailed inspection or a borescope inspection of the slat cans on 
each wing and the lower rail of the slat main tracks for debris, and 
replace the bolts of the aft side guide with new bolts, in 
accordance with the Accomplishment Instructions of Boeing Alert

[[Page 1301]]

Service Bulletin 737-57A1302, dated December 15, 2008 (``the service 
bulletin''); except, where the service bulletin specifies to replace 
the slat main track or contact Boeing for further repair 
instructions if the hole diameter is greater than 0.5005 inch, 
before further flight replace the slat main track in accordance with 
the service bulletin or repair using a method approved in accordance 
with the procedures specified in paragraph (j) of this AD. If debris 
is found during any inspection required by this AD, before further 
flight, remove the debris in accordance with the Accomplishment 
Instructions of the service bulletin. Doing the actions required by 
paragraph (i) of this AD terminates the actions required by 
paragraphs (g) and (h) of this AD.

Alternative Methods of Compliance

    (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: Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, 
FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 917-6440; fax (425) 917-6590. Or, e-mail 
information to [email protected].
    (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.
    (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 the 
Boeing Commercial Airplanes Organization Designation Authorization 
(ODA) that 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.
    (4) AMOCs approved previously in accordance with AD 2007-18-52 
are approved as AMOCs for the corresponding provisions of this AD.

     Issued in Renton, Washington, on December 23, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-187 Filed 1-8-10; 8:45 am]
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