[Federal Register Volume 74, Number 177 (Tuesday, September 15, 2009)]
[Proposed Rules]
[Pages 47148-47150]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-22081]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2009-0788; Directorate Identifier 2009-NM-193-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-300, -400, and -500
Series Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: We propose to adopt a new airworthiness directive (AD) for
certain Boeing Model 737-300, -400, and -500 series airplanes. This
proposed AD would require repetitive external non-destructive
inspections to detect cracks in the fuselage skin along the chem-mill
step at stringers S-1 and S-2 right, between station (STA) 827 and STA
847, and repair if necessary. This proposed AD results from a report of
a hole in the fuselage skin common to stringer S-1 and S-2 left,
between STA 827 and STA 847 on an airplane that diverted to an
alternate airport due to cabin depressurization. We are proposing this
AD to detect and correct fatigue cracking of the fuselage skin panels
at the chem-milled steps, which could result in sudden fracture and
failure of the fuselage skin panels, and consequent rapid decompression
of the airplane.
DATES: We must receive comments on this proposed AD by October 30,
2009.
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 proposed AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax 206-766-5680; e-mail [email protected];
Internet https://www.myboeingfleet.com. You may review copies of the
referenced service information at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information
on the availability of this material at the FAA, call 425-227-1221 or
425-227-1152.
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-2009-0788;
Directorate Identifier 2009-NM-193-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 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 one report from an operator of a hole in the
fuselage skin common to stringer S-1 and S-2 left, between station
(STA) 827 and STA 847. The crack started along the chem-mill edge along
stringer S-1. The airplane skin in the area had 20-inch tear strap
bays, and a structural full pad up doubler provision for an emergency
locator transmitter (ELT) antenna at this location. The airplane
diverted to an alternate airport due to cabin depressurization and
subsequent deployment of the oxygen masks. The airplane had accumulated
42,569 total flight cycles. The cause of the fatigue cracking is under
investigation. Airplanes with 10-inch tear strap bays are also
susceptible to cracks at this location. This condition, if not
corrected, could result in sudden fracture and failure of the fuselage
skin panels, and consequent rapid decompression of the airplane.
Relevant Service Information
We have reviewed Boeing Alert Service Bulletin 737-53A1301, dated
September 3, 2009. The service bulletin describes procedures for
repetitive external non-destructive inspections (NDI) to detect cracks
in the fuselage skin along the chem-mill step at stringers S-1 and S-2
right, between STA 827 and STA 847, and contacting Boeing for repair
instructions. The NDI inspections that can be used are medium frequency
eddy current, magneto optical imaging, or c-scan. The service bulletin
specifies that it is not necessary to inspect the chem-mill steps under
an existing repair doubler provided all of the following apply:
The repair was installed after the release date of the
service bulletin;
The repair was approved by the FAA or by a Boeing Company
Authorized Representative who was authorized by the FAA to make such
findings; and
The repair extends a minimum of three rows of fasteners on
each side of the chem-mill line in the circumferential direction.
FAA's Determination and Requirements of This Proposed AD
We are proposing this AD because we evaluated all relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.
This proposed AD would require accomplishing the actions specified in
the service information described previously, except as discussed under
``Differences Between the Proposed AD and the Service Bulletin.''
Operators should note that paragraph (i) of this AD specifies
certain conditions for terminating the repetitive
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inspections required by this AD for a repaired area only. One of those
conditions is that the external repair doubler be installed after
September 3, 2009. This is the date Boeing Service Bulletin 737-53A1301
became available to operators to address the identified unsafe
condition. In any case, an initial inspection, as required by paragraph
(g) of this AD, must still be accomplished.
Differences Between the Proposed AD and the Service Bulletin
Boeing Alert Service Bulletin 737-53A1301, dated September 3, 2009,
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.
Interim Action
We consider this proposed AD interim action. If final action is
later identified, we might consider further rulemaking then.
Costs of Compliance
We estimate that this proposed AD would affect 135 airplanes of
U.S. registry. The following table provides the estimated costs for
U.S. operators to comply with this proposed AD.
Table--Estimated Costs
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Average Number of U.S.-
Action Work hours labor rate Cost per product registered Fleet cost
per hour airplanes
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Inspection............................ 2 $80 $160, per inspection 135 $21,600, per inspection cycle.
cycle.
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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 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 this 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.
You can find our regulatory evaluation and the estimated costs of
compliance in the AD Docket.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, 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 AD:
Boeing: Docket No. FAA-2009-0788; Directorate Identifier 2009-NM-
193-AD.
Comments Due Date
(a) We must receive comments by October 30, 2009.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737-300, -400, and -500
series airplanes, certificated in any category; as identified in
Boeing Alert Service Bulletin 737-53A1301, dated September 3, 2009.
Subject
(d) Air Transport Association (ATA) of America Code 53:
Fuselage.
Unsafe Condition
(e) This AD results from a report of a hole in the fuselage skin
common to stringer S-1 and S-2 left, between STA 827 and STA 847 on
an airplane that diverted to an alternate airport due to cabin
depressurization and subsequent deployment of the oxygen masks. We
are issuing this AD to detect and correct fatigue cracking of the
fuselage skin panels at the chem-milled steps, which could result in
sudden fracture and failure of the fuselage skin panels, and
consequent rapid decompression of the airplane.
Compliance
(f) 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
(g) Before the accumulation of 35,000 total flight cycles, or
within 500 flight cycles after the effective date of this AD,
whichever occurs later: Except as provided by paragraph (i) of this
AD, do an external non-destructive inspection (NDI) to detect cracks
in the fuselage skin along the chem-mill steps at stringers S-1 and
S-2 right, between STA 827 and STA 847, in accordance with the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1301, dated September 3, 2009. If no cracking is found, repeat
the inspection thereafter at intervals not to exceed 500 flight
cycles, except as provided by paragraph (i) of this AD.
Repair
(h) If any crack is found during any inspection required by this
AD, and Boeing Alert Service Bulletin 737-53A1301, dated September
3, 2009, specifies to contact Boeing for repair instructions: Before
further flight, repair the crack using a method
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approved in accordance with the procedures specified in paragraph
(j) of this AD.
Optional Terminating Action for Repetitive Inspections
(i) Installing an external repair doubler along the chem-milled
steps at stringers S-1 and S-2 right, between STA 827 and STA 847,
constitutes terminating action for the repetitive inspections
required by paragraph (g) of this AD for the repaired area only,
provided all of the conditions specified in paragraphs (i)(1),
(i)(2), and (i)(3) of this AD are met. The initial inspection
required by paragraph (g) of this AD must be accomplished.
(1) The repair is installed after September 3, 2009;
(2) The repair was approved by the FAA or by a Boeing Company
Authorized Representative who was authorized by the FAA to make such
findings; and
(3) The repair extends a minimum of three rows of fasteners on
each side of the chem-mill line in the circumferential direction.
Alternative Methods of Compliance (AMOCs)
(j)(1) The Manager, Seattle Aircraft Certification Office (ACO),
FAA, has the authority to approve AMOCs for this AD, if requested
using the procedures found in 14 CFR 39.19. Send information to
ATTN: 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. Or, e-mail information to [email protected].
(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 principal maintenance inspector (PMI) or
principal avionics inspector (PAI), as appropriate, or lacking a
principal inspector, your local Flight Standards District Office.
The AMOC approval letter must specifically reference this AD.
(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 September 4, 2009.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E9-22081 Filed 9-14-09; 8:45 am]
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