```

[Federal Register Volume 78, Number 124 (Thursday, June 27, 2013)]
[Proposed Rules]
[Pages 38608-38610]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-15425]

========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================


Federal Register / Vol. 78, No. 124 / Thursday, June 27, 2013 / 
Proposed Rules

[[Page 38608]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0538; Directorate Identifier 2012-NM-212-AD]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and 
-500 series airplanes. This proposed 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 proposed AD would 
require repetitive inspections for any cracking of stringer splices and 
butt straps, and related corrective and investigative actions if 
necessary. We are proposing 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: We must receive comments on this proposed AD by August 12, 2013.

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, WA 98057-3356; phone: (425) 917-6447; 
fax: (425) 917-6590; email: wayne.lockett@faa.gov.

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-2013-0538; 
Directorate Identifier 2012-NM-212-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 197 stringer splice cracks at body station 
(STA) 360 and STA 908, between stringer (S) S-10L and S-10R; 16 butt 
strap cracks between S-5L and S-3L, and S-3R and S-5R; and 12 vertical 
chem-mill fuselage skin cracks at certain butt joints. On one airplane, 
a maintenance inspection found that all three structural elements were 
cracked. Analysis indicates the cracking of the stringer splices is 
attributed to airplane fatigue loads. Cracking of the butt strap at STA 
360 and STA 908 is attributed to fatigue loading from the S-4 lap 
joint. This condition, if not corrected, could result in the airplane 
not being able to sustain limit load requirements and possibly result 
in uncontrolled decompression.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin 737-53A1322, dated 
November 5, 2012. For information on the procedures and compliance 
times, see this service information at http://www.regulations.gov by 
searching for Docket No. FAA-2013-0538.

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 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.''
    The phrase ``related investigative actions'' might be used in this 
proposed AD. ``Related investigative actions'' are follow-on actions 
that: (1) Are related to the primary actions, and (2) are actions that 
further investigate the nature of any condition found. Related 
investigative

[[Page 38609]]

actions in an AD could include, for example, inspections.
    In addition, the phrase ``corrective actions'' might be used in 
this proposed AD. ``Corrective actions'' are actions that correct or 
address any condition found. Corrective actions in an AD could include, 
for example, repairs.

Differences Between the Proposed AD and the Service Information

    Boeing Alert Service Bulletin 737-53A1322, dated November 5, 2012, 
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:
     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.
    Boeing Alert Service Bulletin 737-53A1322, dated November 5, 2012, 
specifies to contact the manufacturer for instructions on how to 
inspect airplanes having line number 1 through 291, but this proposed 
AD would require inspections in accordance with a method we approve.

Costs of Compliance

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

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

    We estimate the following costs to do any necessary replacements 
that would be required based on the results of the proposed 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

    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

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):

The Boeing Company: Docket No. FAA-2013-0538; Directorate Identifier 
2012-NM-212-AD.

(a) Comments Due Date

    We must receive comments by August 12, 2013.

[[Page 38610]]

(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

    Joint Aircraft System Component (JASC)/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 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.

(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 the Related Information 
section of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (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

    (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, WA 98057-3356; 
phone: (425) 917-6447; fax: (425) 917-6590; email: 
wayne.lockett@faa.gov.
    (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 June 13, 2013.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-15425 Filed 6-26-13; 8:45 am]
BILLING CODE 4910-13-P
```