[Federal Register Volume 72, Number 183 (Friday, September 21, 2007)]
[Rules and Regulations]
[Pages 53928-53933]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-18436]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-29089; Directorate Identifier 2007-NM-215-AD; 
Amendment 39-15197; AD 2007-18-52]
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: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment

[[Page 53929]]

adopting airworthiness directive (AD) 2007-18-52 that was sent 
previously to all known U.S. owners and operators of Boeing Model 737-
600, -700, -700C, -800, -900, and -900ER series airplanes by individual 
notices. This AD 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 AD is prompted by reports of parts coming off the main 
slat track downstop assemblies. We are issuing this AD to detect and 
correct loose or missing parts from the main slat track downstop 
assemblies, which could result in a fuel leak and consequent fire.

DATES: This AD becomes effective September 26, 2007 to all persons 
except those persons to whom it was made immediately effective by 
emergency AD 2007-18-52, issued August 28, 2007, which contained the 
requirements of this amendment.
    We must receive comments on this AD by November 20, 2007.

ADDRESSES: Use one of the following addresses to submit comments on 
this AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     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.
     Fax: (202) 493-2251.
     Hand Delivery: Room W12-140 on the ground floor of the 
West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this AD.

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: On August 28, 2007, we issued emergency AD 
2007-18-52, which applies to all Boeing Model 737-600, -700, -700C, -
800, -900, and -900ER series airplanes. That emergency AD superseded 
emergency AD 2007-18-51, described below.

Background

    On August 25, 2007, we issued emergency AD 2007-18-51 for all 
Boeing Model 737-600, -700, -700C, -800, -900, and -900ER series 
airplanes. That AD requires repetitive detailed inspections of the main 
slat track downstop assemblies to verify that proper hardware is 
installed, one-time torquing of the nut and bolt, and corrective 
actions if necessary. Corrective actions include installing a new or 
serviceable part; and doing a detailed inspection of the inside of the 
slat can for foreign object debris (FOD) and damage, and removing any 
FOD and repairing damage that is found.
    That AD resulted from reports of parts of the main slat track 
downstop assembly coming off the main slat track. In one case, a nut 
fell into the slat track housing (referred to as ``slat can'') and, 
during a subsequent slat retraction, the track made contact with the 
nut, pushing it into the wall of the can and puncturing it. That 
operator reported finding fuel leaking from the drain hole in the slat 
track housing at the No. 5 slat track position. In another case, an 
initial investigation revealed that following retraction of the slats 
after landing on a Model 737-800 airplane, loose parts of the main slat 
track downstop assembly punctured the slat can, which resulted in a 
fuel leak and a fire that ultimately destroyed the airplane. We issued 
that AD to detect and correct loose or missing parts from the main slat 
track downstop assemblies, which could result in a fuel leak and 
consequent fire.

Actions Since Issuance of Emergency AD 2007-18-51

    Since the issuance of emergency AD 2007-18-51, we have received 
additional reports of parts coming off the main slat track downstop 
assemblies. In these cases, the parts were found in the bottom of the 
slat track housing (``slat can''). Additionally, in one case, the slat 
can was damaged.
    Based on this new information, we find that the 24-day compliance 
time specified in emergency AD 2007-18-51 for accomplishing the 
detailed inspection of each main slat track downstop assembly to verify 
proper installation of the slat track hardware is not adequate to 
address the unsafe condition. We have determined that the appropriate 
compliance time for this inspection is 10 days after receipt of 
emergency AD 2007-18-52. In addition, we have determined that an 
inspection using borescope techniques in lieu of a detailed inspection 
is acceptable.
    Further, we have determined that by performing the initial detailed 
or borescope inspection within the reduced compliance time of 10 days, 
the compliance time for torquing the nut and bolt can remain at 24 days 
after receipt of emergency AD 2007-18-51.

FAA's Determination and Requirements of This AD

    Since the unsafe condition described is likely to exist or develop 
on other airplanes of the same type design, we issued emergency AD 
2007-18-52 to detect and correct loose or missing parts from the main 
slat track downstop assemblies, which could result in a fuel leak and 
consequent fire.
    This AD supersedes emergency AD 2007-18-51, which required 
repetitive detailed inspections of the main slat track downstop 
assemblies to verify that proper hardware is installed, one-time 
torquing of the nut and bolt, and corrective actions if necessary. 
Corrective actions include installing a new or serviceable part; and 
doing a detailed inspection of the inside of the slat can for foreign 
object debris (FOD) and damage, and removing any FOD and repairing 
damage that is found.
    This AD continues to require the same actions as emergency AD 2007-
18-51, but reduces the compliance time for the initial detailed 
inspection of each main slat track downstop assembly to verify proper 
installation of the slat track hardware from 24 days after receipt of 
emergency AD 2007-18-51 to 10 days after receipt of this new AD. This 
AD also provides an additional inspection method (using borescope 
techniques) in lieu of the detailed inspection.

Clarification of Determining Proper Installation of Hardware

    Operators should note that it was not our intent that the hardware 
for the main slat track downstop assemblies be disassembled to 
determine proper installation of the sleeve. 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. 
Disassembling the parts provides additional opportunities for 
introducing the unsafe condition addressed in this AD. Therefore, we 
have revised paragraph (f) of this AD accordingly.

Clarification of Reference to Boeing Multi Operator Message

    Paragraph (f)(1) of emergency AD 2007-18-51 identified ``Boeing 
Correspondence (Multi Operator Message) Service Request ID 1-523812011, 
issued August 25, 2007,'' as one approved method for verifying proper 
installation; installing a new or serviceable part; and inspecting for

[[Page 53930]]

damage and FOD, and removing FOD and repairing damage. This AD 
identifies that document correctly as ``Boeing Multi Operator Message 
Number 1-523812011-1, issued August 25, 2007.''
    Since the issuance of emergency AD 2007-18-51, Boeing has issued 
Boeing Multi Operator Message Number 1-527463441-1, issued August 28, 
2007. We have referenced that document in this AD as an additional 
approved method for doing the specified actions.
    We found that immediate corrective action was required; therefore, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual notices 
issued on August 28, 2007, to all known U.S. owners and operators of 
Boeing Model 737-600, -700, -700C, -800, -900, and -900ER series 
airplanes. These conditions still exist, and the AD is hereby published 
in the Federal Register as an amendment to section 39.13 of the Federal 
Aviation Regulations (14 CFR 39.13) to make it effective to all 
persons.

Interim Action

    We consider this AD interim action. If final action is later 
identified, we might consider further rulemaking then.

Comments Invited

    This AD is a final rule that involves requirements that affect 
flight safety and was not preceded by notice and an opportunity for 
public comment; however, we invite you to submit any relevant written 
data, views, or arguments regarding this AD. Send your comments to an 
address listed in the ADDRESSES section. Include ``Docket No. FAA-2007-
29089, Directorate Identifier 2007-NM-215-AD,'' at the beginning of 
your comments. We specifically invite comments on the overall 
regulatory, economic, environmental, and energy aspects of the AD that 
might suggest a need to modify it.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this AD. Using the search function of that Web 
site, anyone can find and read the comments in any of our dockets, 
including the name of the individual who sent the comment (or signed 
the comment on behalf of an association, business, labor union, etc.). 
You may review the DOT's complete Privacy Act Statement in the Federal 
Register published on April 11, 2000 (65 FR 19477-78), or you may visit 
http://dms.dot.gov.

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 level of the West Building at the DOT street address stated in 
the ADDRESSES section. Comments will be available in the AD docket 
shortly after the Docket Management System receives them.

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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If this 
emergency regulation is later deemed significant under DOT Regulatory 
Policies and Procedures, we will prepare a final regulatory evaluation 
and place it in the AD Docket. See the ADDRESSES section for a location 
to examine the regulatory evaluation, if filed.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, 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:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

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

2007-18-52 Boeing: Amendment 39-15197. Docket No. FAA-2007-29089; 
Directorate Identifier 2007-NM-215-AD.

Effective Date

    (a) This AD becomes effective September 26, 2007, to all persons 
except those persons to whom it was made immediately effective by 
emergency AD 2007-18-52, issued on August 28, 2007, which contained 
the requirements of this amendment.

Affected ADs

    (b) This AD supersedes emergency AD 2007-18-51, issued August 
25, 2007.

Applicability

    (c) This AD applies to all Boeing Model 737-600, -700, -700C, -
800, -900, and -900ER series airplanes, certificated in any 
category.

Unsafe Condition

    (d) This AD results from additional reports of parts coming off 
the main slat track downstop assemblies. We are issuing this AD to 
detect and correct loose or missing parts from the main slat track 
downstop assemblies, which could result in a fuel leak and 
consequent fire.

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.

    Note 1: Paragraph (f) of this AD merely restates the 
requirements of paragraph (f)(1) of AD 2007-18-51. As allowed by the 
phrase, ``unless the actions have already been done,'' if the 
applicable initial inspections required by paragraph (f)(1) of 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.


[[Page 53931]]



Repetitive Detailed Inspections: New Initial Compliance Time

    (f) Within 10 days after the effective date of this AD: 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 
(h) 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 (h) of this AD. Using Boeing Multi Operator Message Number 
1-523812011-1, issued August 25, 2007; or 1-527463441-1, issued 
August 28, 2007; is one approved method for verifying proper 
installation; installing a new or serviceable part; and inspecting 
for damage and FOD, and removing FOD and repairing damage. Repeat 
the actions required by paragraph (f) of this AD thereafter at 
intervals not to exceed 3,000 flight cycles.

    Note 2: Paragraph (g) of this AD merely restates the 
requirements of paragraph (f)(2) of 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 2007-18-51 has 
already been done, this AD does not require that the torque 
application be repeated.

One-Time Torquing

    (g) Within 24 days after receipt of 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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[GRAPHIC] [TIFF OMITTED] TR21SE07.042

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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.
    (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.
    (4) AMOCs approved previously in accordance with AD 2007-18-51 
are approved as AMOCs for the corresponding provisions of this AD.

Material Incorporated by Reference

    (i) None.

    Issued in Renton, Washington, on September 10, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-18436 Filed 9-20-07; 8:45 am]
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