[Federal Register: November 13, 2007 (Volume 72, Number 218)]
[Proposed Rules]
[Page 63831-63833]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr13no07-16]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-0184; Directorate Identifier 2007-NM-140-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (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 various repetitive
inspections for cracking of the upper frame to side frame splice of the
fuselage, and other specified and corrective actions if necessary. This
proposed AD also provides for an optional preventive modification,
which would terminate the repetitive inspections. This proposed AD
results from a report that the upper frame of the fuselage was severed
between stringers S-13L and S-14L at station 747, and the adjacent
frame at station 767 had a 1.3-inch-long crack at the same stringer
location. We are proposing this AD to detect and correct fatigue
cracking of the upper frame to side frame splice of the fuselage, which
could result in reduced structural integrity of the frame and adjacent
lap joint. This reduced structural integrity can increase loading in
the fuselage skin, which will accelerate skin crack growth and result
in decompression of the airplane.
DATES: We must receive comments on this proposed AD by December 28,
2007.
ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Portal: Go to http://www.regulations.gov.
Follow the instructions for submitting comments.
Fax: 202-493-2251.
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.
Hand Delivery: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE., Washington, DC 20590, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
For service information identified in this AD contact Boeing
Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.
Examining the AD Docket
You may examine the AD docket on the Internet at http://www.regulations.gov
; or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Office (telephone 800-647-5527) is in the
ADDRESSES section. Comments will be available in the AD docket shortly
after receipt.
FOR FURTHER INFORMATION CONTACT: Wayne Lockett, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425)
917-6447; fax (425) 917-6590.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2007-0184;
Directorate Identifier 2007-NM-140-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will
[[Page 63832]]
consider all comments received by the closing date and may amend this
proposed AD because of those comments.
We will post all comments we receive, without change, to http://www.regulations.gov
, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.
Discussion
We have received a report indicating that the upper frame of the
fuselage was severed between stringers S-13L and S-14L at station 747
on one airplane that had completed 41,000 total flight cycles, and that
the adjacent frame at station 767 had a 1.3-inch-long crack at the same
stringer location. This incident occurred on a Model 737-300 airplane.
All cracks in the upper frame originated from the upper end fastener
hole of the frame splice common to the fail safe chord. This condition,
if not corrected, could result in reduced structural integrity of the
frame and adjacent lap joint. This reduced structural integrity can
increase loading in the fuselage skin, which will accelerate skin crack
growth and result in decompression of the airplane.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 737-53A1261,
including Appendices A through X inclusive, dated January 19, 2006. The
service bulletin describes the following procedures for various
repetitive inspections for cracking of the upper frame to side frame
splice of the fuselage, and other specified and corrective actions if
necessary. The inspections and other specified and corrective actions
are described below:
Configuration 1 airplanes on which the preventive
modification specified in Boeing Service Bulletin 737-53-1125 has been
done: Perform repetitive medium frequency eddy current (MFEC)
inspections for cracking of the upper frame, repair of any crack before
further flight, an optional preventive modification, which would
eliminate the need for the repetitive inspections. The preventive
modification also involves a high frequency eddy current (HFEC)
inspection for cracking of the fastener holes in the upper frame and
side frame, repair of any crack before further flight, and if no crack
is found, fabricating and installing a modification angle as defined in
the applicable Appendix.
Configuration 2 airplanes on which the frame repair
specified in Boeing Service Bulletin 737-53-1125 has been done: Perform
a detailed inspection of the frame repair to make sure it follows the
repair given in the applicable Boeing Model 737 Structural Repair
Manual (SRM). If the repair is not as given in the SRM, perform any
applicable corrective actions. Then perform an HFEC inspection for
cracking of the upper frame. If any crack is found, repair before
further flight. If no crack is found, repeat the HFEC inspection or
contact Boeing for applicable terminating action, which would eliminate
the need for the repetitive inspections.
Configuration 3 airplanes on which the actions specified
in Boeing Service Bulletin 737-53-1125 have not been done: Perform an
MFEC inspection for cracking of the upper frame. The MFEC inspection is
not necessary if the preventive modification is being accomplished. If
any crack is found, repair before further flight. If no crack is found,
repeat the MFEC inspection or do the preventive modification, which
would eliminate the need for the repetitive inspections. When doing the
preventive modification, perform an HFEC inspection for cracking of the
fastener holes in the upper frame and side frame. If any crack is
found, repair before further flight. If no crack is found, fabricate
and install a modification angle as defined in the applicable Appendix.
The service bulletin specifies a compliance time for the initial
inspection ranging between 30,000 total flight cycles and 50,000 total
flight cycles, with a grace period of 5,000 flight cycles after the
release date of the service bulletin, whichever occurs later, depending
on airplane configuration.
The corrective actions include repair of any cracks found and
ensuring that the frame maintains its structural integrity. If, during
the accomplishment of the corrective actions, the structure that has
been damaged is not covered in the structural repair manual, the
service bulletin specifies contacting Boeing for repair. The service
bulletin also describes procedures for a preventive modification of the
frame splice joints which would eliminate the need for the repetitive
inspections. In addition, the service bulletin recommends contacting
Boeing for certain repair instructions and terminating action for
certain airplanes.
Accomplishing the actions specified in the service information is
intended to adequately address the unsafe condition.
Other Related Service Information
Boeing Alert Service Bulletin 737-53A1261 refers to Boeing Message
M-7200-02-01294, dated August 20, 2002, as an additional source of
service information for accomplishing certain repairs and optional
terminating action of the preventive modification.
Boeing Service Bulletin 737-53-1125, dated November 22, 1989,
Revision 1, dated September 20, 1990, and Revision 2, dated November
21, 1991, provided a preventive modification to reduce the stress level
at the first fastener location in the frame splice common to the fail
safe chord. The preventive modification increased the fatigue life of
the splice area. However, the service bulletin did not include adequate
inspections for cracks prior to accomplishing the preventive
modification; therefore, the inspections specified in Boeing Alert
Service Bulletin 737-53A1261 (described above) are recommended on
airplanes on which that preventive modification has been accomplished
in accordance with Boeing Service Bulletin 737-53-1125.
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. For this reason, we are proposing this AD,
which would require accomplishing the actions specified in the service
information described previously, except as discussed under
``Difference Between the Proposed AD and Alert Service Bulletin.''
Difference Between Proposed AD and Alert Service Bulletin
The service bulletin specifies to contact the manufacturer for
instructions on how to repair certain conditions, but this proposed AD
would require repairing those conditions in one of the following ways:
Using a method that we approve; or
Using data that meet the certification basis of the
airplane, and that have been approved by an Authorized Representative
for the Boeing Commercial Airplanes Delegation Option Authorization
Organization whom we have authorized to make those findings.
Costs of Compliance
There are about 1509 airplanes of the affected design in the
worldwide fleet. This proposed AD would affect about 524 airplanes of
U.S. registry. The proposed inspections would take between 18 and 38
work hours per airplane, depending on airplane configuration, at an
average labor rate of $80 per work hour. Based on these figures, the
estimated cost of the
[[Page 63833]]
inspections proposed by this AD for U.S. operators is between $754,560
and $1,592,960, or $1,440 and $3,040 per airplane, per inspection
cycle.
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 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 and placed it in the AD docket. 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 Federal Aviation Administration (FAA) amends Sec. 39.13 by
adding the following new airworthiness directive (AD):
Boeing: Docket No. FAA-2007-0184; Directorate Identifier 2007-NM-
140-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by December
28, 2007.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737-100, -200, -200C, -300,
-400, and -500 series airplanes, certificated in any category; as
identified in Boeing Alert Service Bulletin 737-53A1261, dated
January 19, 2006.
Unsafe Condition
(d) This AD results from a report that the upper frame of the
fuselage was severed between stringers S-13L and S-14L at station
747, and the adjacent frame at station 767 had a 1.3-inch-long crack
at the same stringer location. We are issuing this AD to detect and
correct fatigue cracking of the upper frame to side frame splice of
the fuselage, which could result in reduced structural integrity of
the frame and adjacent lap joint. This reduced structural integrity
can increase loading in the fuselage skin, which will accelerate
skin crack growth and result in 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.
Repetitive Inspections/Corrective Actions
(f) At the applicable compliance time listed in paragraph 1.E.,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1261,
including Appendices A through X inclusive, dated January 19, 2006:
Do the applicable inspections for cracking of the upper frame to
side frame splice of the fuselage by doing all of the actions, as
specified in the Accomplishment Instructions of the service
bulletin; except as provided by paragraphs (g) and (h) of this AD.
Do all applicable specified and corrective actions before further
flight in accordance with the service bulletin. Repeat the
applicable inspections thereafter at intervals not to exceed 6,000
flight cycles until the terminating action in paragraph (i) of this
AD has been accomplished.
(g) If any crack is found during any inspection required by this
AD, and the service bulletin specifies to contact Boeing for
appropriate action: Before further flight, repair the crack in
accordance with the procedures specified in paragraph (j) of this
AD.
(h) If, during the accomplishment of the corrective actions
required by paragraph (f) of this AD, the structure that has been
damaged is not covered in the structural repair manual, before
further flight, repair in accordance with the procedures specified
in paragraph (j) of this AD.
Optional Terminating Action
(i) Accomplishing the actions specified in paragraph (i)(1)
(i)(2) or (i)(3) of this AD, as applicable, terminates the
repetitive inspections required by paragraph (f) of this AD for the
repaired or modified frames only.
(1) Accomplishment of the repair specified in Part 3 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1261, including Appendices A through X inclusive, dated January
19, 2006, or the preventive modification specified in Part 4 of the
Accomplishment Instructions of the service bulletin.
(2) Accomplishment of the repair or the preventive modification
specified in Boeing Message M-7200-02-01294, dated August 20, 2002.
(3) Accomplishment of the repair or the preventive modification
in accordance with a method approved by the Manager, Seattle ACO.
Alternative Methods of Compliance (AMOCs)
(j)(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) 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.
Issued in Renton, Washington, on November 5, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-22104 Filed 11-9-07; 8:45 am]
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