[Federal Register Volume 77, Number 181 (Tuesday, September 18, 2012)]
[Proposed Rules]
[Pages 57529-57531]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-22890]
[[Page 57529]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2012-0937; Directorate Identifier 2011-NM-270-AD]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company 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 The Boeing Company Model 737-800 series airplanes. This
proposed AD was prompted by reports of early fatigue cracks at chem-
mill areas on the crown skin panels. This proposed AD would require
repetitive inspections for cracking of the fuselage skin along chem-
mill steps at certain crown skin and shear wrinkle areas, and repair if
necessary. We are proposing this AD to detect and correct fatigue
cracking of the skin panel at the specified chem-mill step locations,
which could result in rapid decompression of the airplane.
DATES: We must receive comments on this proposed AD by November 2,
2012.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, 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: Deliver to Mail address above 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, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-766-5680; 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.
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 (phone: 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; phone: (425) 917-
6447; fax: (425) 917-6590; email: [email protected].
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include ``Docket No. FAA-2012-0937;
Directorate Identifier 2011-NM-270-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 received reports of early fatigue cracks near chem-mill areas on
the crown skin panels of Model 737-300, -400, and -500 series
airplanes. The cracks resulted from high stresses in the areas where
chem-mill pockets are adjacent to non-chem-mill areas. Although we have
not received any reports of this type of fuselage fatigue cracks on
Model 737-600, -700, -700C, -800, -900, or -900ER series airplanes, a
full-scale fatigue test article was inspected for skin cracks at
similar structural details and two chem-mill cracks were found that
occurred late in the testing program. This condition, if not detected
and corrected, could result in rapid decompression of the airplane.
Relevant Service Information
We reviewed Boeing Service Bulletin 737-53-1311, dated October 21,
2011, for Model 737-800 series airplanes. That service bulletin
describes, among other things, procedures for doing repetitive external
detailed inspections and external non-destructive inspections (medium
frequency eddy current (MFEC), magneto optic imager (MOI), C-scan, or
ultrasonic phased array (UTPA) inspections) of the fuselage skin at
specified locations where chem-mill areas are adjacent to non-chem-mill
areas at antenna and door bearstrap installations, and shear wrinkle
areas at stringers 9 and 10 between stations 500E and 500G; and repairs
if necessary.
Boeing Service Bulletin 737-53-1311, dated October 21, 2011, also
describes procedures for installing modification doublers in certain
locations, which involves an external detailed inspection and an
external non-destructive (MFEC, MOI, C-scan, or UTPA) inspection for
any cracking of the area to be modified prior to the doubler being
placed on that area, a high frequency eddy current inspection of all
existing holes for cracking as applicable, and contacting Boeing if
necessary. That service bulletin also specifies that when a
modification is accomplished, the repetitive inspection for the area
under the modification is no longer necessary.
Boeing Service Bulletin 737-53-1311, dated October 21, 2011,
specifies an initial compliance time of 43,000 total flight cycles, or
1,500 to 2,100 flight cycles (depending on group/configuration) after
the original issue date of that service bulletin, whichever occurs
later. That service bulletin specifies a repetitive interval not to
exceed 1,500 flight cycles, 2,100 flight cycles, or 2,700 flight cycles
depending on inspection method and group configuration.
For airplanes that have incorporated Boeing Business Jet (BBJ)
lower cabin altitude supplemental type certificate (STC) ST010697SE,
Boeing Service Bulletin 737-53-1311, dated October 21, 2011, specifies
that all initial compliance times specified in flight cycles must be
reduced to half of those specified in that service bulletin, and all
repeat interval compliance times specified in flight cycles must be
reduced to one-quarter of those specified in that service bulletin.
FAA's Determination
We are proposing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or
[[Page 57530]]
develop in other products of the same type design.
Proposed AD Requirements
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
Information.''
Similar Rulemaking
The crown skin panels on Model 737-800 series airplanes are of a
similar design to those on Model 737-300, -400, -500, -600, -700, -
700C, -900, and -900ER series airplanes. Therefore, all these models
may be subject to the identified unsafe condition. We are considering
similar rulemaking for these additional models.
Differences Between the Proposed AD and the Service Information
Boeing Service Bulletin 737-53-1311, dated October 21, 2011,
specifies to contact the manufacturer for disposition of certain repair
conditions, but this proposed AD would require repairing those
conditions in one of the following ways:
In accordance with a method that we approve; or
Using data that meet the certification basis of the
airplane, and that have been approved by the Boeing Commercial
Airplanes Organization Designation Authorization (ODA) whom we have
authorized to make those findings.
Tables 3 and 4 in paragraph 1.E., ``Compliance,'' of Boeing Service
Bulletin 737-53-1311, dated October 21, 2011, specify post-modification
inspections at certain chem-mill step locations, which may be used in
support of compliance with section 121.1109(c)(2) or 129.109(c)(2) of
the Federal Aviation Regulations (14 CFR 121.1109(c)(2) or
129.109(c)(2)). However, this NPRM does not propose to require those
post-modification inspections. This difference has been coordinated
with Boeing.
Costs of Compliance
We estimate that this proposed AD affects 441 airplanes of U.S.
registry.
We estimate the following costs to comply with this proposed AD:
Estimated Costs
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Cost on U.S.
Action Labor cost Parts cost Cost per product operators
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Inspection of chem-mill step 30 work-hours x None............... $2,550 per $1,124,550 per
locations. $85 per hour = inspection cycle. inspection cycle.
$2,550 per
inspection cycle.
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We have received no definitive data that would enable us to provide
cost estimates for the on-condition actions specified in this proposed
AD.
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),
(3) Will not affect intrastate aviation in Alaska, and
(4) 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.
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
airworthiness directive (AD):
The Boeing Company: Docket No. FAA-2012-0937; Directorate Identifier
2011-NM-270-AD.
(a) Comments Due Date
We must receive comments by November 2, 2012.
(b) Affected ADs
None.
(c) Applicability
This AD applies to The Boeing Company Model 737-800 series
airplanes, certificated in any category, as identified in Boeing
Service Bulletin 737-53-1311, dated October 21, 2011.
(d) Subject
Joint Aircraft System Component (JASC)/Air Transport Association
(ATA) of America Code 53; Fuselage.
(e) Unsafe Condition
This AD was prompted by reports of early fatigue cracks at chem-
mill areas on the crown skin panels. We are issuing this AD to
detect and correct fatigue cracking of the skin panel at the
specified chem-mill step locations, which could result in rapid
decompression of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
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(g) Inspections of Crown Skin Areas
At the applicable time specified in paragraph 1.E.,
``Compliance,'' of Boeing Service Bulletin 737-53-1311, dated
October 21, 2011, except as required by paragraph (k) of this AD: Do
an external detailed inspection and an external non-destructive
inspection (a medium frequency eddy current (MFEC), magneto optic
imager (MOI), C-scan, or ultrasonic phased array (UTPA) inspection)
for cracking in the fuselage skin along the chem-mill steps at
certain locations specified in, and in accordance with, Boeing
Service Bulletin 737-53-1311, dated October 21, 2011. Repeat the
inspections thereafter at the applicable times specified in
paragraph 1.E., ``Compliance,'' of Boeing Service Bulletin 737-53-
1311, dated October 21, 2011.
(h) Inspections of Shear Wrinkle Areas
For Groups 2, 5, and 6 airplanes as identified in Boeing Service
Bulletin 737-53-1311, dated October 21, 2011: At the applicable time
specified in paragraph 1.E., ``Compliance,'' of Boeing Service
Bulletin 737-53-1311, dated October 21, 2011, except as required by
paragraph (k) of this AD, do an external detailed inspection and an
external non-destructive inspection (MFEC, MOI, C-scan, or UTPA) for
cracking in the fuselage skin along the chem-mill steps at certain
shear wrinkle locations specified in, and in accordance with, Boeing
Service Bulletin 737-53-1311, dated October 21, 2011. Repeat the
inspections required by paragraph (h) of this AD thereafter at the
applicable times specified in paragraph 1.E., ``Compliance,'' of
Boeing Service Bulletin 737-53-1311, dated October 21, 2011.
(i) Repairs
If any cracking is found during any inspection required by
paragraphs (g) and (h) of this AD, before further flight, repair the
cracking using a method approved in accordance with the procedures
specified in paragraph (m) of this AD. Accomplishing the repair
approved in accordance with the procedures specified in paragraph
(m) of this AD terminates the repetitive inspection requirement for
that area under the repair only.
(j) Optional Terminating Modification
Modification of an inspection area specified in paragraph (g) of
this AD, including doing an external detailed inspection and an
external non-destructive inspection (MFEC, MOI, C-scan, or UTPA) for
cracking of the area to be modified, and a high frequency eddy
current inspection of all existing holes for cracking as applicable,
in accordance with the Accomplishment Instructions of Boeing Service
Bulletin 737-53-1311, dated October 21, 2011, terminates the
repetitive inspections required by paragraph (g) of this AD for that
area only. If any cracking is found during any inspection described
by this paragraph, before further flight, repair the cracking using
a method approved in accordance with the procedures specified in
paragraph (m) of this AD.
(k) Service Bulletin Exception
Boeing Service Bulletin 737-53-1311, dated October 21, 2011,
specifies compliance times ``after the original issue date of this
service bulletin.'' However, this AD requires compliance within the
specified compliance times ``after the effective date of this AD.''
(l) Post-Modification Inspections
The post-modification inspections specified in Tables 3 and 4 of
paragraph 1.E., ``Compliance,'' of Boeing Service Bulletin 737-53-
1311, dated October 21, 2011, are not required by this AD.
Note 1 to paragraph (l) of this AD: The damage tolerance
inspections specified in Tables 3 and 4 of paragraph 1.E.,
``Compliance,'' of Boeing Service Bulletin 737-53-1311, dated
October 21, 2011, may be used in support of compliance with section
121.1109(c)(2) or 129.109(c)(2) of the Federal Aviation Regulations
(14 CFR 121.1109(c)(2) or 14 CFR 129.109(c)(2)). The actions
specified in Part 5 of the Accomplishment Instructions and
corresponding figures of Boeing Service Bulletin 737-53-1311, dated
October 21, 2011, are not required by this AD.
(m) Alternative Methods of Compliance (AMOCs)
(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. In accordance with 14
CFR 39.19, send your request to your principal inspector or local
Flight Standards District Office, as appropriate. If sending
information directly to the manager of the ACO, send it to the
attention of the person identified in the Related Information
section of this AD. Information may be emailed to: [email protected].
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the local flight standards district office/certificate holding
district office.
(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 the
Boeing Commercial Airplanes Organization Designation Authorization
(ODA) that 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.
(n) Related Information
(1) For more information about this AD, contact Wayne Lockett,
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue SW., Renton, Washington
98057-3356; phone: (425) 917-6447; fax: (425) 917-6590; email:
[email protected].
(2) For service information identified in this AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-766-5680; 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.
Issued in Renton, Washington, on September 4, 2012.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2012-22890 Filed 9-17-12; 8:45 am]
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