[Federal Register: November 24, 2004 (Volume 69, Number 226)]
[Proposed Rules]
[Page 68268-68270]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24no04-15]
[[Page 68268]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2004-19682; Directorate Identifier 2004-NM-88-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800
Series Airplanes
AGENCY: Federal Aviation Administration (FAA), 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, -700, -700C, and -800 series
airplanes. This proposed AD would require inspecting/measuring the
length of the attachment fasteners between the nacelle support fittings
and the lower wing skin panels, and related investigative/corrective
actions if necessary. This proposed AD is prompted by a report from the
manufacturer that in production, during the installation of certain
attachment fasteners for the nacelle support fittings, only one washer
was installed instead of two. We are proposing this AD to prevent
inadequate fastener clamp-up, which could result in cracking of the
fastener holes, cracking along the lower wing skin panels, fuel leaking
from the wing fuel tanks onto the engines, and possible fire.
DATES: We must receive comments on this proposed AD by January 10,
2005.
ADDRESSES: Use one of the following addresses to submit comments on
this proposed 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: Docket Management Facility, U.S. Department of
Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401,
Washington, DC 20590.
By fax: (202) 493-2251.
Hand Delivery: Room PL-401 on the plaza level of the
Nassif Building, 400 Seventh Street SW., Washington, DC, 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, P.O. Box 3707, Seattle, Washington 98124-
2207.
You can examine the contents of this AD docket on the Internet at
http://dms.dot.gov, or at the Docket Management Facility, U.S.
Department of Transportation, 400 Seventh Street SW., room PL-401, on
the plaza level of the Nassif Building, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Robert Hardwick, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)
917-6457; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
Docket Management System (DMS)
The FAA has implemented new procedures for maintaining AD dockets
electronically. As of May 17, 2004, new AD actions are posted on DMS
and assigned a docket number. We track each action and assign a
corresponding directorate identifier. The DMS AD docket number is in
the form ``Docket No. FAA-2004-99999.'' The Transport Airplane
Directorate identifier is in the form ``Directorate Identifier 2004-NM-
999-AD.'' Each DMS AD docket also lists the directorate identifier
(``Old Docket Number'') as a cross-reference for searching purposes.
Comments Invited
We invite you to submit any written relevant data, views, or
arguments regarding this proposed AD. Send your comments to an address
listed under ADDRESSES. Include ``Docket No. FAA-2004-19682;
Directorate Identifier 2004-NM-88-AD'' in the subject line of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of the proposed AD. We will
consider all comments submitted by the closing date and may amend the
proposed AD in light of those comments.
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 proposed AD. Using the search function of
that website, 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 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.
We are reviewing the writing style we currently use in regulatory
documents. We are interested in your comments on whether the style of
this document is clear, and your suggestions to improve the clarity of
our communications that affect you. You can get more information about
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.Examining
the Docket
You may examine the AD docket in person at the Docket Management
Facility office between 9 a.m. and 5 p.m., Monday through Friday,
except Federal holidays. The Docket Management Facility office
(telephone (800) 647-5227) is located on the plaza level of the Nassif
Building at the DOT street address stated in the ADDRESSES section.
Comments will be available in the AD docket shortly after the DMS
receives them.
Discussion
We have received a report indicating that, during the production of
certain Boeing Model 737-600, -700, -700C, and -800 series airplanes,
it was discovered that certain attachment fasteners that attach the
nacelle support fittings to the lower wing skin panels were improperly
installed. The affected fasteners were installed during production with
only one washer instead of two, which could cause the nut to tighten
against the thread runout on the fastener shank rather than clamping
the joint. This condition can be identified by checking the thread
protrusion between the top of the nut and the end of the fastener to
determine if the thread protrusion is outside of the limits specified
by the manufacturer. Discrepant thread protrusion could indicate
inadequate clamp-up between the nacelle support fittings and the lower
wing skin panels. Adequate clamp-up compresses the components together,
which assists in preventing cracking. Inadequate clamp-up, if not
corrected, could result in cracking of the fastener holes, cracking
along the lower wing skin panels, fuel leaking from the wing fuel tanks
onto the engines, and possible fire.
Relevant Service Information
We have reviewed Boeing Service Bulletin 737-57-1275, dated
September 4, 2003. The service bulletin describes procedures for
inspecting/measuring the thread protrusion of certain attachment
fasteners between the lower wing skin panels and the nacelle support
fittings, marking fasteners with measurements outside of the specified
thread protrusion limits, and related investigative and corrective
actions. For fasteners with measurements outside of
[[Page 68269]]
the specified limits, the related investigative actions include reaming
the affected fastener holes and doing a high frequency eddy current
inspection of the complete fastener hole stack-up for cracking. If no
cracking is found, the corrective actions include reaming the holes to
the next nominal diameter and installing new fasteners. If cracking is
found, the service bulletin specifies contacting Boeing for repair
information. For repaired areas, the service bulletin also specifies
doing fuel leak inspections. Accomplishing the actions specified in the
service bulletin will 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. Therefore, we are proposing this AD, which
would require inspecting/measuring the length of the attachment
fasteners between the nacelle support fittings and the lower wing skin
panels, and related investigative/corrective actions if necessary. The
proposed AD would require you to use the service information described
previously to perform these actions, except as discussed under
``Differences Between the Proposed AD and Service Information.''
Differences Between the Proposed AD and Service Information
The service bulletin states that the inspection/measurement should
be done within 30,000 flight cycles or 30,000 flight hours from
airplane delivery, whichever is first. For airplanes not modified by
Supplemental Type Certificate (STC) ST00830SE, this proposed AD
specifies doing the inspection/measurement prior to the accumulation of
30,000 total flight cycles or 30,000 total flight hours, whichever is
first. For airplanes modified by that STC, the proposed AD specifies
doing the inspection/measurement prior to the accumulation of 25,000
total flight cycles or 25,000 total flight hours, whichever is first.
The STC is an airplane modification that installs winglets. We have
determined that airplanes with winglets have increased wing loads,
which could result in cracking at a lower threshold than airplanes
without winglets.
The service bulletin also specifies that you may contact the
manufacturer for instructions on how to repair certain conditions, but
this proposed AD would require you to repair those conditions in one of
the following ways:
Using a method that we approve; or
Using data that meet the type certification basis of the
airplane, and that have been approved by a Boeing Company Designated
Engineering Representative who has been authorized by the FAA to make
such findings.
Costs of Compliance
This proposed AD would affect about 751 airplanes worldwide. The
following table provides the estimated costs for U.S. operators to
comply with this proposed AD.
Estimated Costs
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Number of U.S.-
Action Work hours Average labor Parts Cost per registered Fleet cost
rate per hour airplane airplanes
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Inspection/Measurement............... 12 $65 Nominal..................... $780 302 $235,560
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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. 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 FAA amends Sec. 39.13 by adding the following new
airworthiness directive (AD):
Boeing: Docket No. FAA-2004-19682; Directorate Identifier 2004-NM-
88-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive
comments on this AD action by January 10, 2005.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737-600, -700, -700C, and -
800 series airplanes; line numbers 1 through 761 inclusive, except
for line numbers 596, 683, 742, 749, 750, 751, 754, 755, 759, and
760; certificated in any category;
Unsafe Condition
(d) This AD was prompted by a report from the manufacturer that
in production, during installation of certain attachment fasteners
for the nacelle support fittings, only one washer was installed
instead of two. We are issuing this AD to prevent inadequate
fastener clamp-up, which could result in cracking of the fastener
holes, cracking along the lower wing skin panels, fuel leaking from
the wing fuel tanks onto the engines, and possible 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.
Inspection/Measurement and Related Investigative and Corrective Actions
(f) At the applicable time specified in paragraph (f)(1) or
(f)(2) of this AD: Inspect/measure the length of certain attachment
fasteners between the lower wing skin panels and the nacelle support
fittings. Do the inspection/measurement, and all applicable
[[Page 68270]]
related investigative and corrective actions, in accordance with the
Accomplishment Instructions of Boeing Service Bulletin 737-57-1275,
dated September 4, 2003, except as provided by paragraph (g) of this
AD.
(1) For airplanes modified by Supplemental Type Certificate
(STC) ST00830SE as of the effective date of this AD: Prior to the
accumulation of 25,000 total flight hours or 25,000 total flight
cycles, whichever is first.
(2) For airplanes not modified by STC ST00830SE as of the
effective date of this AD: Prior to the accumulation of 30,000 total
flight hours or 30,000 total flight cycles, whichever is first.
(g) If accomplishing a corrective action as required by
paragraph (f) of this AD, and the service bulletin specifies to
contact Boeing for repair information: Before further flight, do the
repair in accordance with a method approved by the Manager, Seattle
Aircraft Certification Office (ACO), FAA; or in accordance with data
meeting the type certification basis of the airplane approved by a
Boeing Company Designated Engineering Representative (DER) who has
been authorized by the Manager, Seattle ACO, to make such findings.
For a repair method to be approved, the approval must specifically
reference this AD.
Alternative Methods of Compliance (AMOCs)
(h)(1) The Manager, Seattle ACO, FAA, has the authority to
approve AMOCs for this AD, if requested using the procedures found
in 14 CFR 39.19.
(2) An AMOC that provides an acceptable level of safety may be
used for any repair required by this AD, if it is approved by a
Boeing Company DER who has been authorized by the Manager, Seattle
ACO, to make such findings. For a repair method to be approved, the
approval must specifically refer to this AD.
Issued in Renton, Washington, on November 10, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-26031 Filed 11-23-04; 8:45 am]
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