[Federal Register Volume 79, Number 26 (Friday, February 7, 2014)]
[Rules and Regulations]
[Pages 7377-7380]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-02419]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0538; Directorate Identifier 2012-NM-212-AD; 
Amendment 39-17728; AD 2014-01-05]
RIN 2120-AA64


Airworthiness Directives; the Boeing Company 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 
the Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 
series airplanes. This AD was prompted by a report of cracks in 
stringer splices at body station STA 360 and STA 908, between stringer 
(S) S-10L and S-10R; cracks in butt straps between S-5L and S-3L, and 
S-3R and S-5R; vertical chem-mill fuselage skin cracks at certain butt 
joints; and an instance of cracking that occurred in all those three 
structural elements on one airplane. This AD requires repetitive 
inspections for any cracking of stringer splices and butt straps, and 
related corrective and investigative actions if necessary. We are 
issuing this AD to detect and correct cracking in the three structural 
elements, which could result in the airplane not being able to sustain 
limit load requirements and possibly result in uncontrolled 
decompression.

DATES: This AD is effective March 14, 2014.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of March 14, 
2014.

ADDRESSES: 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 view this referenced service information 
at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., 
Renton, WA. 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 by searching for and locating Docket No. FAA-2013-
0538; 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 (phone: 800-647-
5527) is Docket 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, WA 98057-3356; phone: (425) 917-6447; 
fax: (425) 917-6590; email: [email protected].

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to certain The Boeing Company 
Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. The 
NPRM published in the Federal Register on June 27, 2013 (78 FR 38608). 
The NPRM was prompted by a report of cracks in stringer splices at body 
station STA 360 and STA 908, between stringer (S) S-10L and S-10R; 
cracks in butt straps between S-5L and S-3L, and S-3R and S-5R; 
vertical chem-mill fuselage skin cracks at certain butt joints; and an 
instance of cracking that occurred in all those three structural 
elements on one airplane. The NPRM proposed to require repetitive 
inspections for any cracking of stringer splices and butt straps, and 
related corrective and investigative actions if necessary. We are 
issuing this AD to detect and correct cracking in the three structural 
elements, which could result in the airplane not being able to sustain 
limit load requirements and possibly result in uncontrolled 
decompression.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
(78 FR 38608, June 27, 2013) and the FAA's response to each comment.

Request to Clarify That Post-Repair Inspections Are Not Required by 
This Final Rule

    Boeing requested clarification that Table 11, ``Stringer Splice 
Post Repair Inspection,'' in paragraph 1.E., ``Compliance,'' of Boeing 
Alert Service Bulletin 737-53A1322, dated November 5, 2012, is not 
required by paragraph (h) of the NPRM (78 FR 38608, June 27, 2013). 
Boeing suggested that paragraph (h) of the NPRM be revised to include 
an exception phrase that references paragraph (i) of the NPRM. Boeing 
stated that the inspections specified in Table 11, ``Stringer Splice 
Post Repair Inspection,'' in paragraph 1.E., ``Compliance,'' of Boeing 
Alert Service Bulletin 737-53A1322, dated November 5, 2012, are 
required to support operating requirements for complying with section 
121.1109(c)(2) or 129.109(b)(2) of the Federal Aviation Regulations (14 
CFR 121.1109(c)(2) or 14 CFR 129.109(b)(2)). Boeing also stated that 
the way the sentences of paragraph (h) of the NPRM are arranged, the 
sentences for doing corrective actions and repeating inspections seem 
to link the corrective actions and the repetitive inspections and imply 
that Table 11, ``Stringer Splice Post Repair Inspection,'' in paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1322, 
dated November 5, 2012, is required by both the NPRM and the Federal 
Aviation Regulations.

[[Page 7378]]

    We agree to provide clarification, but we do not agree to revise 
this final rule. Paragraph (h) of the final rule indicates that after 
the corrective actions are accomplished on a cracked stringer splice, 
the repetitive inspections are terminated for that stringer splice 
only. The sentence that includes the phrase ``repeat the applicable 
inspections'' is not intended to imply any requirement to accomplish 
the post repair inspections specified in Table 11, ``Stringer Splice 
Post Repair Inspection,'' in paragraph 1.E., ``Compliance,'' of Boeing 
Alert Service Bulletin 737-53A1322, dated November 5, 2012. Paragraph 
(i) of this final rule also indicates that accomplishing Table 11, 
``Stringer Splice Post Repair Inspection,'' in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1322, dated 
November 5, 2012, is not required. No change to the final rule is 
necessary in this regard.

Request To Reference Alternative Service Information Instead of 
Contacting the Manufacturer for Corrective Actions

    Southwest Airlines requested that paragraph (j)(1) of the NPRM (78 
FR 38608, June 27, 2013) be revised to reference certain service 
information for corrective action instructions instead of requiring 
corrective actions that involve contacting the FAA or the Boeing 
Commercial Airplanes Organization Designation Authorization (ODA) for 
instructions. Southwest Airlines proposed that paragraph (j)(1) of the 
NPRM be changed to instead require replacement of cracked butt splice 
straps using a Boeing production drawing and require inspections for 
cracking in the fuselage skin using certain portions and revisions of 
Boeing Service Bulletins 737-53A1210 or 737-53A1234. Southwest Airlines 
also suggested referencing Repair 31 of section 53-00-01-2R in the 
Boeing 737-300/-500 Structural Repair Manual as an acceptable means of 
compliance for repairing any cracking or damage found on the fuselage 
skins.
    We do not agree. The specific skin inspection requirements after 
finding a cracked butt joint splice strap might not be covered by the 
inspections provided in Boeing Service Bulletins 737-53A1210 or 737-
53A1234. The specific skin inspection requirements will be developed 
based on the specific butt strap cracking that is found, and specific 
repairs will be developed based on the skin cracking that is found. 
Operators may request approval of an alternative method of compliance 
using the procedures specified in paragraph (k) of this AD. We have not 
changed this final rule in this regard.

Request To Exclude Service Information Note for Corrosion Findings

    Southwest Airlines requested that the NPRM (78 FR 38608, June 27, 
2013) be revised to exclude General Information Note 12 of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1322, dated November 5, 2012, from the required actions of the final 
rule. Southwest Airlines stated that General Information Note 12 
specifies to contact Boeing for repair instructions if corrosion is 
found. Southwest Airlines pointed out that the NPRM does not propose 
any inspections for corrosion and suggested that any findings of 
corrosion during the accomplishment of the requirements of this final 
rule be addressed using the operator's maintenance program.
    We agree to revise this final rule. Cracking, not corrosion, is the 
primary safety concern addressed by this final rule. If any corrosion 
is found during any inspection for cracking that is required by this 
final rule, the corrective action for the corrosion should be provided 
by the operator's maintenance program. We have added paragraph (j)(3) 
to this final rule to remove the requirement to comply with General 
Information Note 12 of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-53A1322, dated November 5, 2012.

Request To Exclude Service Information Note for Deviations From 
Modification Drawings

    Southwest Airlines requested that paragraph (j) of the NPRM (78 FR 
38608, June 27, 2013) be revised to provide an exclusion of General 
Information Note 16 from the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-53A1322, dated November 5, 2012. Southwest 
Airlines describes General Information Note 16 as specifying to contact 
Boeing if the fastener patterns, types, and sizes, or the structure 
does not agree with the production drawing requirements or applicable 
modification drawing requirements. Southwest Airlines stated that since 
there are previous FAA-approved repairs and deviations to modification 
drawings, and the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1322, dated November 5, 2012, specify actions to remove 
and install structure and fasteners, Southwest Airlines expected to 
encounter numerous conditions that would prevent complying with the 
actions detailed in the figures of Boeing Alert Service Bulletin 737-
53A1322, dated November 5, 2012.
    We do not agree to exclude General Information Note 16 from the 
requirements of this final rule to accomplish actions in accordance 
with the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-53A1322, dated November 5, 2012. The previously approved repairs or 
deviations to modification drawings may require changes to the 
inspection methods used and structure that may require removal to 
accomplish the inspection required by this final rule. Any change from 
the procedures specified in the service information must be approved as 
an AMOC under paragraph (k) of the final rule. We have not changed this 
final rule in this regard.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
this AD with the changes described previously and minor editorial 
changes. We have determined that these minor changes:
     [Agr]re consistent with the intent that was proposed in 
the NPRM (78 FR 38608, June 27, 2013) for correcting the unsafe 
condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM (78 FR 38608, June 27, 2013).
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this AD.

Costs of Compliance

    We estimate that this AD affects 612 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

[[Page 7379]]



                                                 Estimated Costs
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                                                                                                 Cost on U.S.
             Action                  Labor cost           Parts cost       Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Inspections....................  Up to 362 work-     None...............  Up to $30,770, per  Up to $18,831,240,
                                  hours x $85 per                          inspection cycle.   per inspection
                                  hour = $30,770,                                              cycle.
                                  per inspection
                                  cycle.
Removal and reinstallation of    Up to 2 work-hours  $0.................  Up to $170, per     Up to $104,040,
 butt strap fastener(s).          x $85 per hour =                         inspection cycle.   per inspection
                                  $170, per                                                    cycle.
                                  inspection cycle.
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary replacements 
that will be required based on the results of the inspection. We have 
no way of determining the number of aircraft that might need these 
replacements:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                       Cost per
                  Action                            Labor cost                    Parts cost            product
----------------------------------------------------------------------------------------------------------------
Stringer splice replacement..............  3 work-hours x $85 per hour   Operator-supplied,                $255
                                            = $255.                       information not available.
----------------------------------------------------------------------------------------------------------------

    The work-hour estimate and parts cost information are not available 
for estimating the cost of a butt strap replacement.

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),
    (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.

Adoption of the Amendment

    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 airworthiness 
directive (AD):

2014-01-05 The Boeing Company: Amendment 39-17728; Docket No. FAA-
2013-0538; Directorate Identifier 2012-NM-212-AD.

(a) Effective Date

    This AD is effective March 14, 2014.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes, certified in any 
category, as identified in Boeing Alert Service Bulletin 737-
53A1322, dated November 5, 2012.

(d) Subject

    Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by a report of cracks in stringer splices 
at body station STA 360 and STA 908, between stringer (S) S-10L and 
S-10R; cracks in butt straps between S-5L and S-3L, and S-3R and S-
5R; vertical chem-mill fuselage skin cracks at certain butt joints; 
and an instance of cracking that occurred in all those three 
structural elements on one airplane. We are issuing this AD to 
detect and correct cracking in the three structural elements, which 
could result in the airplane not being able to sustain limit load 
requirements and possibly result in uncontrolled decompression.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Actions for Group 1 Airplanes

    For Group 1 airplanes, as identified in Boeing Alert Service 
Bulletin 737-53A1322, dated November 5, 2012: At the compliance time 
specified in paragraph 1.E., ``Compliance,'' of Boeing Alert Service 
Bulletin 737-53A1322, dated November 5, 2012, except as provided by 
paragraph (j)(2) of this AD, inspect the stringers and butt straps 
and repair as applicable, using a method approved in accordance with 
the procedures specified in paragraph (k) of this AD.

(h) Actions for Groups 2 Through 6 Airplanes

    For Groups 2 through 6 airplanes, as identified in Boeing Alert 
Service Bulletin 737-53A1322, dated November 5, 2012: At the 
applicable compliance time specified in paragraph 1.E., 
``Compliance,'' of Boeing

[[Page 7380]]

Alert Service Bulletin 737-53A1322, dated November 5, 2012, do the 
applicable inspections for cracking identified in paragraphs (h)(1) 
through (h)(4) of this AD, and all applicable corrective actions, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-53A1322, dated November 5, 2012, except as 
provided by paragraph (j) of this AD. Do all applicable corrective 
actions before further flight. Thereafter, repeat the applicable 
inspections at the compliance times specified in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1322, dated 
November 5, 2012. Accomplishing the corrective actions for a cracked 
stringer splice, as specified in Boeing Alert Service Bulletin 737-
53A1322, dated November 5, 2012, terminates the repetitive 
inspections required by this paragraph for that stringer splice 
only.
    (1) Internal detailed inspections of the stringer splices and 
butt straps.
    (2) Internal high-frequency eddy current (HFEC) surface 
inspections of the butt straps.
    (3) Internal low-frequency eddy current (LFEC) inspection of the 
butt straps.
    (4) HFEC open hole rotary probe inspections of butt straps or of 
one location of a butt strap, as applicable.

(i) Post-Repair Inspections

    The post-repair inspection specified in Table 11 of paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1322, 
dated November 5, 2012, is not required by this AD.

    Note 1 to paragraph (i) of this AD:  The post-repair inspections 
specified in Table 11 of paragraph 1.E., ``Compliance,'' of Boeing 
Alert Service Bulletin 737-53A1322, dated November 5, 2012, may be 
used in support of compliance with section 121.1109(c)(2) or 
129.109(b)(2) of the Federal Aviation Regulations (14 CFR 
121.1109(c)(2) or 14 CFR 129.109(b)(2)). The corresponding actions 
specified in the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1322, dated November 5, 2012, are not required by 
this AD.

(j) Exceptions to the Service Information

    (1) Where Boeing Alert Service Bulletin 737-53A1322, dated 
November 5, 2012, specifies to contact Boeing for appropriate 
action: Before further flight, repair using a method approved in 
accordance with the procedures specified in paragraph (k) of this 
AD.
    (2) Where Boeing Alert Service Bulletin 737-53A1322, dated 
November 5, 2012, specifies a compliance time ``after the original 
issue date of this service bulletin,'' this AD requires compliance 
within the specified compliance time after the effective date of 
this AD.
    (3) Where General Information Note 12 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1322, dated 
November 5, 2012, specifies contacting Boeing, this AD does not 
require the actions specified in that note.

(k) 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 paragraph (l) 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.

(l) Related Information

    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, WA 98057-3356; 
phone: (425) 917-6447; fax: (425) 917-6590; email: 
[email protected].

(m) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Service Bulletin 737-53A1322, dated November 5, 
2012.
    (ii) Reserved.
    (3) 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.
    (4) You may view this service information at FAA, FAA, Transport 
Airplane Directorate; 1601 Lind Avenue SW., Renton, WA. For 
information on the availability of this material at the FAA, call 
425-227-1221.
    (5) You may view this service information that is incorporated 
by reference 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/cfr/ibr-locations.html.

    Issued in Renton, Washington, on January 7, 2014.
Jeffrey E. Duven,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2014-02419 Filed 2-6-14; 8:45 am]
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