[Federal Register: September 7, 2004 (Volume 69, Number 172)]
[Proposed Rules]
[Page 54058-54060]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr07se04-17]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2004-19003; Directorate Identifier 2003-NM-245-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 all Boeing Model 737-100, -200, -200C, -300, -400, and -500 series
airplanes. This proposed AD would require repetitive inspections for
cracks in the fuselage skin, doubler, bearstrap, and frames surrounding
the main, forward, and aft cargo doors; and repair of any cracking.
This proposed AD also would require inspections of certain existing
repairs for cracking, and related corrective action if cracking is
found. This proposed AD is prompted by reports of multiple fatigue
cracks in the fuselage skin and bonded skin doubler, bearstrap, and
doorway frames surrounding the forward and aft cargo doors. We are
proposing this AD to find and fix fatigue cracking in the fuselage
skin, doubler, bearstrap, and frames, which could result in reduced
structural integrity of the frames, possible loss of a cargo door, and
consequent rapid decompression of the fuselage.
DATES: We must receive comments on this proposed AD by October 22,
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 in person 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:
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-2004-19003;
Directorate Identifier 2003-NM-245-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 can review DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78), or you
can 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.
Background
The FAA previously issued related rulemaking applicable to certain
Boeing Model 737 series airplanes, as follows:
AD 88-11-12, amendment 39-5890 (53 FR 18077, May 20, 1988). That AD
requires structural inspection of the forward lower cargo doorway
frames, and repair if necessary. That AD also requires replacement of
certain repaired parts previously installed.
AD 93-14-10, amendment 39-8634 (58 FR 43547, August 17, 1993). That
AD requires structural inspections to detect cracks of the forward and
aft body frames adjacent to the aft lower cargo door and repair of
cracked parts, and provides an optional modification. That AD also
requires certain repetitive inspections to continue after installation
of the optional modification.
FAA's Determination Since Issuance of AD 88-11-12 and AD 93-14-10
Since we issued those ADs, we have received reports of multiple
fatigue cracks in the fuselage skin and bonded skin doubler, bearstrap,
and doorway frames surrounding the forward and aft cargo doors on
certain Boeing Model
[[Page 54059]]
737 series airplanes. Several cracks have also been found in the
fuselage skin/doubler and bearstrap of the upper corners of the main
cargo door. Additionally, during structural inspections, cracks were
found in the bearstrap under the fuselage frame flanges at the edges of
the forward cargo door. In two cases, cracks were found in the fuselage
frames of the aft cargo door where steel repair doublers had been
installed using the requirements of AD 93-14-10. In another case,
cracks were found in the unreinforced area above the aluminum repair
doubler, which had also been installed using the requirements of AD 93-
14-10. A recent inspection done on an airplane having 73,080 total
flight cycles revealed cracks in the forward fuselage frame and
adjacent skin/doubler and bearstrap of the forward cargo door. Such
fatigue cracking, if not found and fixed, could result in reduced
structural integrity of the frames, possible loss of a cargo door, and
consequent rapid decompression of the fuselage.
Explanation of Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 737-53A1228, dated
July 10, 2003, which describes procedures for repetitive detailed,
general visual, and high and low frequency eddy current inspections for
cracks in the fuselage skin, doubler, bearstrap, and frames surrounding
the main, forward, and aft cargo doors, and repair of any crack found.
The service bulletin also describes procedures for repetitive
inspections for cracks in certain existing repairs in the subject
areas, and related corrective action.
The corrective action includes alternative inspections or
replacement of the repaired component, depending on the cracking damage
found. The service bulletin recommends that operators contact Boeing
for certain repair instructions. Accomplishment of the actions
specified in the service bulletin is intended to adequately address the
identified unsafe condition.
This service bulletin recommends compliance times at the following
approximate intervals:
1. For the detailed and general inspections of the forward and aft
cargo door cutouts, the inspection threshold is before the accumulation
of 50,000 total flight cycles or within 4,000 flight cycles after
release of the service bulletin, whichever is later. The inspections
are repeated at intervals ranging from 4,000 flight cycles to 12,000
flight cycles.
2. For the detailed and high frequency eddy current (HFEC)
inspections of the main cargo door cutout, the inspection threshold is
before the accumulation of 20,000 total flight cycles or within 4,000
flight cycles after release of the service bulletin, whichever is
later. The inspections are repeated at intervals not to exceed 12,000
flight cycles.
3. For the detailed and HFEC inspections of the forward cargo
doorway frame, the inspection threshold is before the accumulation of
20,000 total flight cycles or within 4,000 flight cycles after release
of the service bulletin, whichever is later. The inspections are
repeated at intervals not to exceed 4,000 flight cycles.
4. For the general visual, HFEC and low frequency eddy current
inspections of the aft cargo doorway frame, the inspection threshold
ranges between 20,000 and 40,000 total flight cycles or within 4,000
flight cycles after release of the service bulletin, whichever is
later. The inspections are repeated at intervals not to exceed 4,000
flight cycles.
5. If the frame is replaced, the inspection threshold starts from
the time the frame was replaced. If the frame is repaired, the
inspection threshold starts from the time the repair was installed, or
the total airplane cycles if it is unknown when the repair was
installed.
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. The proposed AD would require you to use the
service information described previously to perform the actions, except
as discussed under ``Differences Between the Proposed AD and Service
Bulletin.''
Differences Between Proposed AD and Service Bulletin
The service bulletin specifies compliance times relative to the
date of the service bulletin; however, this proposed AD would require
compliance within the thresholds specified in paragraph 1.E.,
``Compliance'' of the service bulletin, after the effective date of the
AD.
The service bulletin recommends reporting any discrepancies to the
manufacturer; however, this proposed AD does not include that
requirement.
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 using a
method approved by the Manager of the Seattle Aircraft Certification
Office of the FAA, or using 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.
Costs of Compliance
There are about 3,132 airplanes of the affected design in the
worldwide fleet. We estimate that 870 airplanes of U.S. registry would
be affected by this proposed AD. We provide the following cost
estimates to comply with this proposed AD, per inspection cycle:
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Hourly Cost per
Group Work hours labor rate Parts airplane
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1........................................................... 24 $65 $0 $1,560
2 and 4..................................................... 28 65 0 1,820
3 and 5..................................................... 30 65 0 1,950
6 and 7..................................................... 28 65 0 1,820
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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.
[[Page 54060]]
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-2004-19003; Directorate Identifier 2003-NM-
245-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive
comments on this AD action by October 22, 2004.
Affected ADs
(b) None.
Applicability
(c) This AD applies to all Model 737-100, -200, -200C, -300, -
400, and -500 series airplanes; certificated in any category.
Unsafe Condition
(d) This AD was prompted by reports of multiple fatigue cracks
in the fuselage skin and bonded skin doubler, bearstrap, and doorway
frames surrounding the forward and aft cargo doors. We are issuing
this AD to find and fix fatigue cracking in the fuselage skin,
doubler, bearstrap, and frames, which could result in reduced
structural integrity of the frames, possible loss of a cargo door,
and consequent rapid decompression of the fuselage.
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.
Initial and Repetitive Inspections/Corrective Action
(f) Do the applicable detailed, general visual, and low and high
frequency eddy current inspections for cracks in the fuselage skin,
doubler, bearstrap, and frames surrounding the main, forward, and
aft cargo doors, and for cracks in existing repairs, as specified in
Tables 1, 2, and 3, as applicable, of paragraph 1.E.,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1228, dated
July 10, 2003. Do the inspections at the initial compliance times
listed in Tables 1, 2, and 3, as applicable, of paragraph 1.E.,
``Compliance,'' of the service bulletin; except, where the service
bulletin specifies a compliance time after the service bulletin
date, this AD requires compliance within the specified compliance
time after the effective date of this AD. Do the inspections in
accordance with the Accomplishment Instructions of the service
bulletin. Repeat the inspections within the repetitive inspection
intervals listed in Tables 1, 2, and 3 of paragraph 1.E.,
``Compliance,'' of the service bulletin.
(g) If any crack is found during any inspection: Repair before
further flight in accordance with the Accomplishment Instructions of
Boeing Alert Service Bulletin 737-53A1228, dated July 10, 2003.
Where the service bulletin specifies contacting the manufacturer for
disposition of certain repair conditions, repair before further
flight 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 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.
No Reporting Required
(h) Although the service bulletin referenced in this AD
recommends reporting any discrepancies to the manufacturer, this AD
does not include that requirement.
Alternative Methods of Compliance (AMOCs)
(i)(1) The Manager, Seattle ACO, 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 any repair required by this AD, if it is approved by a
Boeing Company Designated Engineering Representative who has been
authorized by the Manager, Seattle ACO, to make those findings. For
a repair method to be approved, the approval must specifically refer
to this AD.
Issued in Renton, Washington, on August 26, 2004.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-20209 Filed 9-3-04; 8:45 am]
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