[Federal Register: July 8, 2008 (Volume 73, Number 131)]
[Rules and Regulations]
[Page 38905-38908]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08jy08-10]
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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;
Amendment 39-15575; AD 2008-13-12]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: We are adopting a new airworthiness directive (AD) for certain
Boeing Model 737-100, -200, -200C, -300, -400, and -500 series
airplanes. This AD requires 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 AD also provides
for an optional preventive modification, which terminates the
repetitive inspections. 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.
DATES: This AD is effective August 12, 2008.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of August 12,
2008.
ADDRESSES: 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 AD, the regulatory evaluation,
any comments received, and other information. The address for the
Docket Office (telephone 800-647-5527) is the Document Management
Facility, U.S. Department of Transportation, Docket Operations, M-30,
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE.,
Washington, DC 20590.
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:
Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to include an airworthiness directive (AD) that would apply to
certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series
airplanes. That NPRM was published in the Federal Register on November
13, 2007 (72 FR 63831). That NPRM proposed to 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. That NPRM also provides for an optional preventive
modification, which would terminate the repetitive inspections.
Comments
We gave the public the opportunity to participate in developing
this AD. We considered the comments received.
Requests To Clarify Certain Paragraphs
Boeing, Southwest Airlines (SWA), United Airlines (UA), and the Air
Transport Association (ATA) on behalf of its member UA, ask that
certain language in certain paragraphs of the NPRM be clarified, as
follows:
Boeing states that the intent of paragraph (h) of the NPRM is
unclear, and the conditional statement could be misinterpreted. Boeing
notes that the statement ``the structure that has been damaged is not
covered in the structural repair manual'' (SRM) will likely be
interpreted differently by each airline. Boeing adds that this frame
area is relatively complex with a frame splice, stringer clips, and, in
some cases, a shear tie in the area of the repair. Boeing states that
only specific SRM repairs can be used to fix the frame in this complex
area; for that reason, the referenced service bulletin specifically
lists the SRM sections that can be used, and recommends contacting
Boeing if the existing repairs are not per these sections. Boeing notes
that there are other frames and general formed section repairs in the
SRM that operators could have used that may or may not work for this
area; for those cases or others that may not have been repaired in
accordance with the SRM, Boeing would like to evaluate them for
structural adequacy. Boeing believes the intent of paragraph (h) is to
cover this situation, except to refer to paragraph (j) of the NPRM
instead of contacting Boeing. Boeing recommends that paragraph (h) be
rewritten as follows: ``If during the accomplishment of the corrective
actions required by paragraph (f) of this AD, for airplanes for which a
repair has previously been accomplished, if the repair is not per the
737-400 SRM 53-00-07, Figure 201, Repair 1, or 737-500 SRM 53-00-07,
Figure 201, Repair 1, or 737-300 SRM 53-00-07, Figure 201, Repair 1, or
737-100/200 SRM 53-10-4, Figure 1, as applicable, before further
flight, repair in accordance with the procedures specified in paragraph
(j) of this AD.''
ATA states that UA indicates that the term ``structural repair
manual,'' as specified in paragraph (h) of the NPRM, should be replaced
with ``Service Bulletin 737-53A1261 Part III.''
We agree that paragraph (h) of this AD should be clarified; there
are many repairs for this structure specified in the SRM that could be
installed which may not adequately address the unsafe condition.
Therefore, we have changed paragraph (h) for clarification, as follows:
``For airplanes on which a repair has been previously accomplished: If,
during accomplishment of the corrective actions required by paragraph
(f) of this AD, it is found that the repair was not done per the Boeing
737-100/200 SRM 53-10-4, Figure 1, or the Boeing 737-300/400/500 SRM
53-00-07, Figure
[[Page 38906]]
201, Repair 1, as applicable; before further flight, repair in
accordance with the procedures specified in paragraph (k) of this AD.''
SWA requests clarification of paragraphs (h) and (i) of the NPRM.
SWA states that if an SRM repair is considered a repair option to
inspection findings per Boeing Alert Service Bulletin 737-53A1261,
dated January 19, 2006, as indicated in paragraph (h) of the NPRM, then
paragraph (i) of the NPRM should specify that SRM repairs would be an
alternative method of compliance (AMOC) and terminating action to the
inspections specified in that service bulletin.
We do not agree that paragraph (i) of the NPRM should be changed to
specify that SRM repairs are an AMOC and terminating action to the
inspections specified in the service bulletin. The SRM is referenced in
the service bulletin as an acceptable method for accomplishing certain
repairs; therefore, it is not necessary to identify the SRM in
paragraph (i) because the service bulletin (which includes the SRM
contents) is already identified in that paragraph. We have made no
change to the AD in this regard.
Boeing asks that we clarify paragraph (i)(1) of the NPRM to include
a reference to Appendices A through X to the service bulletin citation,
for not only the repair, but also the preventive modification. Boeing
recommends that paragraph (i)(1) be rewritten as follows:
``Accomplishment of the repair specified in Part 3, or the preventive
modification specified in Part 4 of the Accomplishment Instructions of
Boeing Alert Service Bulletin 737-53A1261, including Appendices A
through X inclusive, dated January 19, 2006.'' Boeing adds that
paragraph (i)(1) as currently written does not associate the appendices
to the preventive modification. Appendices A through V of the service
bulletin are directly applicable to the preventive modification.
We agree that paragraph (i)(1) of the NPRM (paragraph (j)(1) of
this AD) should be clarified to add a reference to Appendices A through
X to the service bulletin citation. This change links the appendices to
the preventive modification, as well as the repair. We have changed
paragraph (j)(1) accordingly.
UA asks that we clarify paragraph (i)(3) of the NPRM. UA notes that
previously installed SRM repairs do not terminate re-inspections;
although paragraph (i)(3) may lead an operator to think a previously
installed SRM repair does terminate those inspections, as they are
approved by the Manager, Seattle Aircraft Certification Office.
We understand UA's comment. As we explained previously, for
clarification we have added a new paragraph (i) to this AD to define
the action for airplanes on which a repair has been previously
accomplished. Paragraph (j) of this AD, if accomplished, terminates the
repetitive inspections required by paragraph (f) of this AD for the
repaired or modified frames only. We have made no change to the AD in
this regard.
Request To Clarify Certain Sections of the Preamble of the NPRM
Boeing requests that certain sections in the preamble of the NPRM
be clarified for the following reasons:
1. Boeing states that the first paragraph of the Discussion section
incorrectly references a Model 737-300 airplane, but the airplane found
cracked was a Model 737-200 airplane.
2. Boeing notes that the last sentence specified in the Other
Related Service Information section specifies that the inspections are
``recommended.'' Boeing states that the inspections are ``required,''
and suggests incorporating this change to the language.
We acknowledge the commenter's concern. However, the procedures
specified in the service information are not regulatory; the procedures
specified in service information can only be required by issuing an AD.
We agree that the model referenced in the Discussion section was
incorrect; however, the identified sections of the NPRM do not reappear
in the final rule. Therefore, we find that no change to the AD is
necessary in this regard.
Requests To Extend Compliance Times
SWA, KLM Royal Dutch Airlines (KLM), and UA ask that we extend the
compliance times for the inspections as follows:
SWA asks that we consider a different compliance time for airplanes
that have accomplished Boeing Service Bulletin 737-53A1177, since the
likelihood of multi-element damage does not exist for airplanes on
which that service bulletin has been accomplished at stringer 14 left
or right. SWA recommends aligning the initial grace period and repeat
intervals at the same frequency as defined in Boeing Service Bulletin
737-53-1216, section 1.E.; i.e., 9,000 flight cycles after issuance of
the AD, and repeating the inspections thereafter every 9,000 flight
cycles. SWA adds that this will align the interior access and
inspection requirements with the frame inspection requirements in both
service bulletins. SWA notes that the 9,000-flight-cycle interval would
also allow each airplane to reach a heavy maintenance opportunity for
the airplane to be in an appropriate setting for accomplishing the
required inspections and repairs if required. SWA adds that it had
several crack findings on airplanes with over 50,000 flight cycles, and
therefore it cannot consider the Boeing findings an anomaly.
KLM states that it submitted a service request to Boeing asking
them to consider a compliance time for Boeing Alert Service Bulletin
737-53A1261, which is equal to the compliance time given in AD 2006-26-
09, amendment 39-14867 (72 FR 252, January 4, 2007), and Boeing Special
Attention Service Bulletin 737-53-1216, Revision 1, dated June 8, 2006.
KLM states that both inspections can then be done simultaneously during
a C-check, without additional work. KLM adds that Boeing replied to the
service request in October 2006 stating that no change in compliance
time was anticipated. KLM notes that the impact of the inspection/
preventive modification required by AD 2006-26-09 is similar to the
inspection/preventive modification in the NPRM.
ATA on behalf of its member UA asks that we consider extending the
repetitive inspection interval from 6,000 to 9,000 flight cycles in
order to allow airplanes to reach a heavy maintenance opportunity. To
date, UA states, it has inspected 960 frames per Boeing Alert Service
Bulletin 737-53A1261 with no crack findings; the airplanes inspected
ranged from 28,500 to 35,500 total flight cycles. UA suggests that the
findings on the airplanes cited in the NPRM might be an anomaly rather
than a trend if other industry findings are similar to UA's.
We do not agree to extend the compliance times. Although we
recognize the convenience to the operator if the compliance time is
aligned with its maintenance inspections, fatigue cracking of the upper
frame to side frame splice of the fuselage is a significant safety
issue, and we have determined that the proposed compliance times are
warranted based on the effectiveness of the inspection procedure and
the rate of crack growth. In developing appropriate compliance times
for this AD, we considered those safety issues as well as the
recommendations of the manufacturer, the availability of necessary
repair parts, and the practical aspect of accomplishing the required
inspections within an interval of time that corresponds to the normal
maintenance schedules of most affected operators. We have made no
change to the AD in this regard.
[[Page 38907]]
Request for Clarification of Compliance Time
KLM states that it assumes the new start date of the inspections
will be the issue date of the AD, instead of the service bulletin issue
date.
From this statement we infer that KLM is requesting that we clarify
the compliance time specified in paragraph (f) of the NPRM. We agree
that clarification is necessary. We have added a new paragraph (g) to
the AD to clarify the compliance time. We have re-identified subsequent
paragraphs accordingly.
Request To Change Cost Estimate
SWA states that the costs of compliance identified in the NPRM are
underestimated. SWA states that the inspection, repair of crack
findings, and terminating action on uncracked frames is close to 1,200
labor hours at an average labor rate of $80 per work hour. The cost per
airplane is closer to $96,000 than $3,040. This estimate does not
include access to the interior of the airplanes, as the airplanes were
in a heavy maintenance environment.
We infer that the commenter is asking that we revise the cost
estimate provided in the NPRM. We do not agree. The cost information
provided in AD actions describes only the direct costs of the specific
requirements. Based on the best data available, the manufacturer
provided the number of work hours to do the required actions for this
AD. We recognize that, in doing the actions required by an AD,
operators might incur incidental costs, in addition to the direct
costs. The cost analysis in AD rulemaking actions, however, typically
does not include incidental costs such as the time required to gain
access and close up, time necessary for planning, or time necessitated
by other administrative actions. Those incidental costs, which might
vary significantly among operators, are almost impossible to calculate.
We have made no change to the AD in this regard.
Conclusion
We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting
the AD with the changes described previously. We also determined that
these changes will not increase the economic burden on any operator or
increase the scope of the AD.
Costs of Compliance
There are about 1,509 airplanes of the affected design in the
worldwide fleet. This AD affects about 524 airplanes of U.S. registry.
The inspections 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
inspections required 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
This AD will not have federalism implications under Executive Order
13132. This AD will 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 this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Is not a ``significant rule'' under 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.
Adoption of the Amendment
0
Accordingly, under the authority delegated to me by the Administrator,
the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
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]
0
2. The FAA amends Sec. 39.13 by adding the following new AD:
2008-13-12 Boeing: Amendment 39-15575. Docket No. FAA-2007-0184;
Directorate Identifier 2007-NM-140-AD.
Effective Date
(a) This airworthiness directive (AD) is effective August 12,
2008.
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;
except as provided by paragraph (g) of this AD: 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 (h) and (i) 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 (j) of this AD has been
accomplished.
(g) Where Boeing Alert Service Bulletin 737-53A1261, including
Appendices A
[[Page 38908]]
through X inclusive, dated January 19, 2006, specifies a compliance
time relative to the date on the service bulletin, this AD requires
compliance within the specified compliance time after the effective
date of this AD.
(h) If any crack is found during any inspection required by this
AD, and Boeing Alert Service Bulletin 737-53A1261, including
Appendices A through X inclusive, dated January 19, 2006, specifies
to contact Boeing for appropriate action: Before further flight,
repair the crack in accordance with the procedures specified in
paragraph (k) of this AD.
(i) For airplanes on which a repair has been previously
accomplished: If, during accomplishment of the corrective actions
required by paragraph (f) of this AD, it is found that the repair
was not done per the Boeing 737-100/200 Structural Repair Manual
(SRM) 53-10-4, Figure 1, or the Boeing 737-300/400/500 SRM 53-00-07,
Figure 201, Repair 1, as applicable; before further flight, repair
in accordance with the procedures specified in paragraph (k) of this
AD.
Optional Terminating Action
(j) Accomplishing the actions specified in paragraph (j)(1),
(j)(2), or (j)(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, or the
preventive modification specified in Part 4, of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1261, including
Appendices A through X inclusive, dated January 19, 2006.
(2) Accomplishment of the repair or the preventive modification
specified in Boeing Message M-7200-02-01294, dated August 20, 2002.
Alternative Methods of Compliance (AMOCs)
(k)(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.
Material Incorporated by Reference
(l) You must use Boeing Alert Service Bulletin 737-53A1261,
dated January 19, 2006, to do the actions required by this AD,
unless the AD specifies otherwise.
(1) The Director of the Federal Register approved the
incorporation by reference of this service information under 5
U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington
98124-2207.
(3) You may review copies of the service information
incorporated by reference at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the
National Archives and Records Administration (NARA). For information
on the availability of this material at NARA, call 202-741-6030, or
go to: http://www.archives.gov/federal_register/code_of_federal_
regulations/ibr_locations.html.
Issued in Renton, Washington, on June 12, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E8-14471 Filed 7-7-08; 8:45 am]
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