[Federal Register: August 6, 2004 (Volume 69, Number 151)]
[Proposed Rules]
[Page 47808-47811]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr06au04-19]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2004-18788; Directorate Identifier 2003-NM-203-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 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 737-100, -200, -200C, -300, -400, and -500
series airplanes. This proposed AD would require repetitive inspections
of the intercostal webs, attachment clips, and stringer splice channels
for cracks; and corrective action if necessary. This proposed AD is
prompted by reports of fatigue cracks on several Boeing Model 737-200
series airplanes. We are proposing this AD to detect and correct
fatigue cracking of the intercostals on the forward and aft sides of
the forward entry door, which could result in loss of the forward entry
door and rapid decompression of the airplane.
DATES: We must receive comments on this proposed AD by September 20,
2004.
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
[[Page 47809]]
of Transportation, 400 Seventh Street SW., room PL-401, on the plaza
level of the Nassif Building, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Technical Information: Howard Hall,
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6430; fax (425) 917-6590.
Plain Language Information: Marcia Walters, marcia.walters@faa.gov.
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 relevant written data, views, or
arguments regarding this proposed AD. Send your comments to an address
listed under ADDRESSES. Include ``Docket No. FAA-2004-18788;
Directorate Identifier 2003-NM-203-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 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 can 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 can examine the AD docket on the Internet at http://dms.dot.gov
, or 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 eleven operators have
found fatigue cracks in the intercostal web at body station (BS) 358.5
and stringer (S) S-16L on several Boeing Model 737-200 series
airplanes. The cracks extended from the inboard edge of the intercostal
through tooling or fastener holes and terminated at the two-inch
diameter lightening hole. Three operators have also reported four
airplanes with cracks in the intercostals at S-11L, S-12L, and S-13L on
the forward and aft sides of the forward entry door. All additional
cracks are in the radius of return flanges of the webs and attachment
clips. One operator has reported one airplane with cracks in the
stringer splice channels at S-14L and S-15L on the aft side of the
forward entry door. The cracks were in the intercostal web attachment
flange at the aft end of the intercostal. Such fatigue cracking, if not
detected and corrected in a timely manner, could result in loss of the
forward entry door and rapid decompression of the airplane.
The intercostal webs, attachment clips, and stringer splice
channels on certain Boeing Model 737-100, -200C, -300, -400, and -500
series airplanes are identical to those on the affected Boeing Model
737-200 series airplanes. Therefore, all of these models may be subject
to the same unsafe condition.
Relevant Service Information
We have reviewed Boeing Special Attention Service Bulletin 737-53-
1204, dated June 19, 2003. The service bulletin describes procedures
for detailed and high frequency eddy current inspections (as
applicable) of the intercostal webs, attachment clips, and stringer
splice channels for cracks; and corrective actions if necessary. The
corrective actions include repairing cracks and contacting Boeing for
certain repair instructions.
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 repetitive inspections of the intercostal webs,
attachment clips, and stringer splice channels for cracks; and
corrective action 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 the Service Bulletin.''
Differences Between the Proposed AD and the Service Bulletin
Although the service bulletin specifies that operators may contact
the manufacturer for disposition of certain repair conditions, this
proposed AD would require operators to repair those conditions per a
method approved by the FAA, or per data meeting the type certification
basis of the airplane approved by a Boeing Company Designated
Engineering Representative who has been authorized by the FAA to make
such findings.
The service bulletin specifies to repair any crack found at the S-
16L intercostal (BS 348.2-360) on Boeing Model 737-400 series airplanes
per 737-400 Structural Repair Manual (SRM) 53-10-04, Figure 202. Figure
202 does not exist; the correct figure is 737-400 SRM 53-10-04, Figure
201. Note 2 of this proposed AD points out this error in the service
bulletin.
Paragraphs 3. and 4. of the ``Part 1 for Group 1 passenger
airplanes'' section of the Work Instructions of the service bulletin do
not give instructions for repairing cracks found in the attachment clip
or stringer splice channel during the inspections. Other paragraphs of
the service bulletin give instructions for similar attachment clips and
stringer splice channels. This proposed AD would require operators to
contact the FAA or an FAA-authorized Boeing Delegated Engineer
Representative (DER) for repair instructions and do the repair before
further flight if any crack is found in the attachment clip or stringer
splice channel during the inspections specified in ``Part 1 for Group 1
passenger airplanes.'' If no crack is found in the attachment clip or
[[Page 47810]]
stringer splice channel during the inspections, this proposed AD would
require the repetitive inspections.
The differences discussed above have been coordinated with Boeing.
Costs of Compliance
This proposed AD would affect about 3,113 airplanes worldwide and
876 airplanes of U.S. registry. The proposed actions would take about 2
work hours per airplane, at an average labor rate of $65 per work hour.
Based on these figures, the estimated cost of the proposed AD for U.S.
operators is $113,880, or $130 per airplane, per inspection cycle.
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-2004-18788; Directorate Identifier 2003-NM-
203-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive
comments on this AD action by September 20, 2004.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Model 737-100, -200, -200C, -300, -400,
and -500 series airplanes, as listed in Boeing Special Attention
Service Bulletin 737-53-1204, dated June 19, 2003; certificated in
any category.
Unsafe Condition
(d) This AD was prompted by reports of fatigue cracks on several
Boeing Model 737-200 series airplanes. We are issuing this AD to
detect and correct fatigue cracking of the intercostals on the
forward and aft sides of the forward entry door, which could result
in loss of the forward entry door and rapid decompression 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.
Service Bulletin Definition
(f) The term ``service bulletin,'' as used in this AD, means
Boeing Special Attention Service Bulletin 737-53-1204, dated June
19, 2003.
Initial Compliance Time
(g) Before the accumulation of 15,000 total flight cycles, or
within 4,500 flight cycles after the effective date of this AD,
whichever occurs later: Do the inspections specified in paragraph
(h) or (i) of this AD, as applicable.
Inspection for Passenger Configuration Airplanes
(h) For Group 1 passenger airplanes identified in the service
bulletin: Perform a detailed inspection of the intercostal web,
attachment clips, and stringer splice channels for cracks; and a
high frequency eddy current inspection of the stringer splice
channels, located forward and aft of the forward entry door, for
cracks; per Parts 1 and 2 of the Work Instructions of the service
bulletin.
Inspection for Cargo Configuration Airplanes
(i) For Group 2 cargo airplanes identified in the service
bulletin: Perform a detailed inspection of the intercostal webs and
attachment clips located forward of the forward entry door for
cracks, per Part 3 of the Work Instructions of the service bulletin.
Repetitive Inspections
(j) If no crack is found during any inspection required by
paragraph (h) or (i) of this AD, repeat the inspections at the
applicable time specified in Table 1 of this AD, except as provided
by paragraph (k) of this AD.
Table 1.--Repetitive Inspection Interval
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Airplane group number in Service Repeat inspections at intervals not to
Bulletin For intercostal location-- exceed--
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Group 1............................... S-16L, from BS 348.2 to BS 360 4,500 flight cycles.
(aft of door).
---------------------------------------
Group 1............................... S-7L through S-15L, from BS 25,000 flight cycles.
348.2 to BS 360 (aft of door).
---------------------------------------
Group 1 and 2......................... S-7L through S-16L, from BS 25,000 flight cycles.
294.5 to BS 303.9 (forward of
door).
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Deferral of Certain Repetitive Inspections
(k) For intercostal webs at S-16L from BS 348.2 to BS 360:
Installation of the repair as a preventative modification or
corrective action per Part 1 of the Work Instructions of the service
bulletin defers the repetitive inspections to intervals not to
exceed 25,000 flight cycles. Use 737-400 SRM 53-10-04, Figure 201
instead of Figure 202, as applicable.
Corrective Actions
(l) If any crack is found during any inspection required by
paragraph (h) or (i) of this AD, perform the actions specified in
paragraphs (l)(1) through (l)(3) of Table 2 of this AD, as
applicable. Repeat the inspections at the applicable time specified
in Table 1 of this AD, except as provided by paragraph (k) of this
AD.
[[Page 47811]]
Table 2.--Corrective Actions
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During any inspection specified in-- If any crack is found At intercostal
in-- location-- Before further flight--
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(1) Part 1 of the Work Instructions (i) The intercostal Stringer (S)-16L, from Repair per Part 1 of the
of the service bulletin. web. body station (BS) the Work Instructions of
348.2 to BS 360 (aft the service bulletin,
of door). except where the service
bulletin specifies to
contact Boeing for repair
instructions, before
further flight, do the
repair specified in
paragraph (m) of this AD.
Use 737-400 Structural
Repair Manual (SRM) 53-10-
04, Figure 201 instead of
Figure 202, as applicable
(see note 2).
-------------------------
(ii) An attachment S-16L, from BS 348.2 Do the repair specified in
clip or stringer to BS 360 (aft of paragraph (m) of this AD.
splice channel. door).
------------------------------------
(2) Part 2 of the Work Instructions An intercostal web, S-7L through S-16L, Do the repair specified in
of the service bulletin. attachment clip, or from BS 294.5 to BS paragraph (m) of this AD.
stringer splice 303.9 (forward of
channel. door); and S-7L
through S-15L, from
BS 348.2 to BS 360
(aft of door).
------------------------------------
(3) Part 3 of the Work Instructions An intercostal web or S-7L through S-16L, Do the repair specified in
of the service bulletin. attachment clip. from BS 294.5 to BS paragraph (m) of this AD.
303.9 (forward of
door).
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Note 2: The service bulletin specifies to repair any crack found
at the S-16L intercostal (BS 348.2-360) on Boeing Model 737-400
series airplanes per 737-400 SRM 53-10-04, Figure 202. Figure 202
does not exist; the correct figure is 737-400 SRM 53-10-04, Figure
201.
Repair
(m) At the time specified in Table 2 of this AD, repair per a
method approved by the Manager, Seattle Aircraft Certification
Office (ACO), FAA; or per data meeting the type certification basis
of the airplane approved by a Boeing Company Designated Engineering
Representative 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)
(n)(1) The Manager, Seattle 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) An AMOC that provides an acceptable level of safety may be
used for corrective actions, if it is approved by a Boeing Company
Designated Engineering Representative who has been authorized by the
Manager, Seattle ACO, to make those findings.
Issued in Renton, Washington, on July 30, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-17988 Filed 8-5-04; 8:45 am]
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