[Federal Register: March 6, 2009 (Volume 74, Number 43)]
[Proposed Rules]
[Page 9776-9778]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr06mr09-12]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2008-0669; Directorate Identifier 2007-NM-350-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-600, -700, and -800
Series Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Supplemental notice of proposed rulemaking (NPRM); reopening of
comment period.
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SUMMARY: We are revising an earlier proposed airworthiness directive
(AD) for certain Boeing Model 737-600, -700, and -800 series airplanes.
The original NPRM would have required an inspection of the free flange
of the lower stringers of the wing center section for drill starts, and
applicable related investigative and corrective actions. The original
NPRM resulted from drill starts being found on the free flange of the
lower stringers of the wing center section during a quality assurance
inspection at the final assembly plant. This action revises the
original NPRM by expanding the inspection area to include the free
flange, the vertical web, and the fillet radius between the vertical
web and the free flange. We are proposing this supplemental NPRM to
prevent cracks from propagating from drill starts in the free flange,
vertical web, and radius between the free flange and vertical web of
the lower stringers of the wing center section lower stringers, which
could cause a loss of structural integrity of the wing center section
and may result in a fuel leak.
DATES: We must receive comments on this supplemental NPRM by March 31,
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.
[[Page 9777]]
For service information identified in this proposed AD, contact
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207; telephone 206-544-9990; fax 206-766-5682; e-mail DDCS@boeing.com;
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: Nancy Marsh, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425)
917-6440; 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-2008-0669;
Directorate Identifier 2007-NM-350-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 issued a notice of proposed rulemaking (NPRM) (the ``original
NPRM'') to amend 14 CFR part 39 to include an airworthiness directive
(AD) that would apply to certain Boeing Model 737-600, -700, and -800
series airplanes. That original NPRM was published in the Federal
Register on June 24, 2008 (73 FR 35593). That original NPRM proposed to
require inspecting the free flange of the lower stringers of the wing
center section for drill starts, and applicable related investigative
and corrective actions.
Comments
We gave the public the opportunity to participate in developing
this AD. We considered the comment received.
Request To Clarify Inspection Requirements
Boeing notes that the original NPRM would have required an
inspection of the free flange of the stringer, whereas paragraph 3.B.2.
of the Accomplishment Instructions in Boeing Alert Service Bulletin
737-57A1294, dated April 23, 2007, calls for inspection as given in
Figure 1 of the service bulletin. Figure 1 specifies that the free
flange, vertical web, and radius between the free flange and vertical
web must be inspected. (The original NPRM referred to this service
bulletin as the appropriate source of service information for the
proposed actions.) The commenter requests that we clarify whether the
inspection area is to include the free flange, vertical web, and the
fillet radius.
We agree that the original NPRM is unclear whether the inspection
area includes all three parts of the stringer. The service bulletin
does not consistently include all three parts of the stringer. The
``Background'' section, the ``Action'' section, Paragraph 1.C.,
``Reason,'' Paragraph 1.D., ``Description,'' and Paragraph 3.B., ``Work
Instructions,'' refer only to the free flange for the inspection. Only
a note in Figure 1, Sheet 4, contains any reference to all three areas
of inspection--free flange, vertical web, and the fillet radius. We
have determined that all three areas must be inspected to adequately
address the identified unsafe condition. We have revised paragraph (g)
of the supplemental NRPM to explicitly state these three areas of
inspection. We have also revised the description of the area in the
summary and paragraph (e) of the supplemental NPRM.
Actions Since the Original NPRM Was Issued
We have added a new paragraph (d) to this proposed AD to specify
the Air Transport Association (ATA) of America code identifying the
subject, and re-identified the subsequent paragraphs accordingly.
FAA's Determination and Proposed Requirements of the Supplemental NPRM
We are proposing this supplemental NPRM because we evaluated all
pertinent information and determined an unsafe condition exists and is
likely to exist or develop on other products of the same type design.
The change described above expands the scope of the original NPRM. As a
result, we have determined that it is necessary to reopen the comment
period to provide additional opportunity for the public to comment on
this supplemental NPRM.
Costs of Compliance
We estimate that this proposed AD would affect 17 airplanes of U.S.
registry. We also estimate that it would take 7 work-hours per product
to comply with this proposed AD. The average labor rate is $80 per
work-hour. Based on these figures, we estimate the cost of this
proposed AD to the U.S. operators to be $9,520, or $560 per product.
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:
[[Page 9778]]
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-2008-0669; Directorate Identifier 2007-NM-
350-AD.
Comments Due Date
(a) We must receive comments by March 31, 2009.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737-600, -700, and -800
series airplanes, certificated in any category, as identified in
Boeing Alert Service Bulletin 737-57A1294, dated April 23, 2007.
Subject
(d) Air Transport Association (ATA) of America Code 57: Wings.
Unsafe Condition
(e) This AD results from drill starts being found on the free
flange of the lower stringers of the wing center section during a
quality assurance inspection at the final assembly plant. We are
issuing this AD to prevent cracks from propagating from drill starts
in the free flange, vertical web, and radius between the free flange
and vertical web of the lower stringers of the wing center section
lower stringers, which could cause a loss of structural integrity of
the wing center section and may result in a fuel leak.
Compliance
(f) Comply with this AD within the compliance times specified,
unless already done.
Inspection and Related Investigative and Corrective Actions
(g) Before the accumulation of 18,000 total flight cycles, or
within 90 days after the effective date of this AD, whichever occurs
later, do a detailed inspection of the free flange, vertical web,
and radius between the free flange and vertical web of the lower
stringers of the wing center section for any drill start, and do all
applicable related investigative and corrective actions, by
accomplishing all the applicable actions specified in paragraphs
3.B.2 and 3.B.4 of the Accomplishment Instructions of Boeing Alert
Service Bulletin 737-57A1294, dated April 23, 2007; except as
provided in paragraph (h) of this AD. The applicable related
investigative and corrective actions must be done before further
flight.
(h) If any crack is found during any inspection required by
paragraph (g) of this AD, and Boeing Alert Service Bulletin 737-
57A1294, dated April 23, 2007, specifies to contact Boeing for
appropriate action: Before further flight, repair the crack using a
method approved in accordance with the procedures specified in
paragraph (i) of this AD.
Alternative Methods of Compliance (AMOCs)
(i)(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: Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S,
FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW.,
Renton, Washington 98057-3356; telephone (425) 917-6440; fax (425)
917-6590.
(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 February 20, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E9-4732 Filed 3-5-09; 8:45 am]
BILLING CODE 4910-13-P