7-3, slat downtrack assembly

[Federal Register: September 21, 2007 (Volume 72, Number 183)]
[Rules and Regulations]
[Page 53928-53933]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21se07-9]

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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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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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