[Federal Register: November 26, 2007 (Volume 72, Number 226)]
[Proposed Rules]
[Page 65901-65903]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr26no07-6]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2007-0226; Directorate Identifier 2007-NM-187-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-300, -400, and -500
Series Airplanes
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking (NPRM).
-----------------------------------------------------------------------
SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Boeing Model 737-300, -400, and -500 series airplanes. This
proposed AD would require repetitive inspections for cracking of the
body buttock line (BBL) 0.07 floor beam between body station (BS) 651
and BS 676 and between BS 698 and BS 717, and related investigative and
corrective actions if necessary. This AD also provides an optional
terminating action for the repetitive inspections. This proposed AD
results from reports of cracking in the BBL 0.07 floor beam. We are
proposing this AD to prevent failure of the main deck floor beams at
certain body stations due to fatigue cracking, which could result in
rapid decompression of the airplane.
DATES: We must receive comments on this proposed AD by January 10,
2008.
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: Nancy Marsh, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
[[Page 65902]]
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-2007-0226;
Directorate Identifier 2007-NM-187-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.
Other Related Rulemaking
On July 12, 2001, we issued AD 2001-14-20, amendment 39-12331 (66
FR 38354, July 24, 2001), applicable to certain Boeing Model 737-100
and -200 series airplanes. AD 2001-14-20 requires repetitive
inspections to find fatigue cracking in the main deck floor beams
located at certain body stations, and repair if necessary. AD 2001-14-
20 also provides for optional terminating action for the repetitive
inspections. AD 2001-14-20 addresses fatigue cracking in the main deck
floor beams on Model 737-100 and -200 series airplanes, while this
proposed AD would address the same unsafe condition on Boeing Model
737-300, -400, and -500 series airplanes.
Discussion
Since we issued AD 2001-14-20, several operators have reported
cracking in the body buttock line (BBL) 0.07 floor beam on Model 737-
300, -400, and -500 series airplanes. The cracks were similar to those
found on the Model 737-100 and -200 series airplanes, which are
addressed by AD 2001-14-20. Investigation revealed that the cracks were
caused by fatigue resulting from pressurization flexure. Failure of the
main deck floor beam at certain body stations due to fatigue cracking
could result in rapid decompression of the airplane.
Relevant Service Information
We have reviewed Boeing Service Bulletin 737-57-1210, Revision 2,
dated June 13, 2007. For Model 737-300, -400, and -500 series
airplanes, the service bulletin describes procedures for accomplishing
repetitive detailed inspections for cracking of the BBL 0.07 floor beam
between body station (BS) 651 and BS 676 and between BS 698 and BS 717,
and doing related investigative and corrective actions if necessary.
The related investigative action includes doing a high frequency eddy
current (HFEC) inspection of the fastener holes for cracking (1) prior
to modifying the floor beam, or (2) if any cracking is found in the web
(between BS 651 and BS 676 and between BS 698 and BS 717) or in the
upper chord (between BS 651 and BS 676) during the detailed inspection.
The corrective actions include the following:
Repairing any cracking in accordance with the service
bulletin, if cracking is found in the web (between BS 651 and BS 676
and between BS 698 and BS 717) or in the upper chord (between BS 651
and BS 676) during the detailed inspection but no cracking is found
during the HFEC inspection. Accomplishing the repair would eliminate
the need for the repetitive inspections for the area in which the
repair is installed.
Contacting Boeing for repair instructions, (1) if cracking
is found in the web (between BS 651 and BS 676 and between BS 698 and
BS 717) or in the upper chord (between BS 651 and BS 676) during the
HFEC inspections, (2) if cracking is found in the chords or stiffeners
(between BS 698 and BS 717) or outside the typical crack locations
(between BS 651 and BS 676 and between BS 698 and BS 717) during the
detailed inspection, or (3) if cracking is found during the HFEC prior
to modifying the floor beam.
The service bulletin also provides procedures for modifying the
floor beam, if no cracking is found during the detailed and HFEC
inspections. Accomplishing the modification (optional terminating
action) would eliminate the need for the repetitive inspections for the
area in which the modification is installed.
Accomplishing the actions specified in the service information is
intended to adequately address the unsafe condition.
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 Service Bulletin.''
Difference Between the Proposed AD and 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 1,961 airplanes of the affected design in the
worldwide fleet. This proposed AD would affect about 599 airplanes of
U.S. registry. The proposed inspections would take about 4 work hours
per airplane, at an average labor rate of $80 per work hour. Based on
these figures, the estimated cost of the proposed AD for U.S. operators
is $191,680, or $320 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
[[Page 65903]]
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-2007-0226; Directorate Identifier 2007-NM-
187-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by January
10, 2008.
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 Service Bulletin 737-57-1210, excluding Appendix A, Revision
2, dated June 13, 2007.
Unsafe Condition
(d) This AD results from reports of cracking in the body buttock
line (BBL) 0.07 floor beam. We are issuing this AD to prevent
failure of the main deck floor beams at certain body stations due to
fatigue cracking, which could result in 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.
Inspections and Related Investigative/Corrective Actions
(f) Before the accumulation of 20,000 total flight hours, or
within 7,000 flight cycles after the effective date of this AD,
whichever occurs later: Do the detailed inspections for cracking of
the BBL 0.07 floor beam between body station (BS) 651 and BS 676 and
between BS 698 and BS 717, and do all the applicable related
investigative and corrective actions before further flight, by
accomplishing all of the applicable actions specified in paragraphs
B.2. and B.4. of the Accomplishment Instructions of Boeing Service
Bulletin 737-57-1210, excluding Appendix A, Revision 2, dated June
13, 2007, except as provided by paragraph (g) of this AD. Repeat the
inspections thereafter at intervals not to exceed 7,000 flight
cycles. Installing a repair in accordance with paragraphs B.2. and
B.4. of the Accomplishment Instructions of the service bulletin, or
doing the modification in accordance with paragraph (h) of this AD,
terminates the repetitive inspections for the applicable area only.
Exception to Corrective Action
(g) If any cracking is found during any inspection required by
this AD, and Boeing Service Bulletin 737-57-1210, excluding Appendix
A, Revision 2, dated June 13, 2007, specifies to contact Boeing for
appropriate action: Before further flight, repair the cracking using
a method approved in accordance with the procedures specified in
paragraph (i) of this AD.
Optional Terminating Action
(h) If no cracking is found during the detailed inspection and
related investigative action required by paragraph (f) of this AD:
Accomplishing the modification of the BBL 0.07 floor beam between BS
651 and BS 676 and between BS 698 and BS 717, as applicable, in
accordance with paragraphs B.2. and B.4., as applicable, of the
Accomplishment Instructions of Boeing Service Bulletin 737-57-1210,
excluding Appendix A, Revision 2, dated June 13, 2007, terminates
the repetitive inspections for the applicable area only.
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 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 13, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-22923 Filed 11-23-07; 8:45 am]
BILLING CODE 4910-13-P