82 FR 38637 - Airworthiness Directives; The Boeing Company Airplanes

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

Federal Register Volume 82, Issue 156 (August 15, 2017)

We propose to supersede Airworthiness Directive (AD) 2012-12- 05, which applies to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. AD 2012-12-05 currently requires repetitive inspections for cracking under the stop fittings and intercostal flanges and for cracking of the intercostal web, attachment clips, stringer splice channels, frame, reinforcement angle, shear web, frame outer chord and inner chord; a one-time inspection to detect missing fasteners; repetitive inspections of the cargo barrier net fitting for cracking; repetitive inspections for cracking of the stringer S-15L aft intercostal; and repair or corrective action if necessary. Since we issued AD 2012-12-05, we have received reports of additional cracking in locations not covered by the inspections in that AD. For certain airplanes, this proposed AD would add new repetitive inspections of certain areas of the frame inner chord, and applicable on-condition actions. We are proposing this AD to address the unsafe condition on these products.

[Federal Register Volume 82, Number 156 (Tuesday, August 15, 2017)]
[Proposed Rules]
[Pages 38637-38641]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2017-16776]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0774; Product Identifier 2017-NM-036-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 supersede Airworthiness Directive (AD) 2012-12-
05, which applies to all The Boeing Company Model 737-100, -200, -200C, 
-300, -400, and -500 series airplanes. AD 2012-12-05 currently requires 
repetitive inspections for cracking under the stop fittings and 
intercostal flanges and for cracking of the intercostal web, attachment 
clips, stringer splice channels, frame, reinforcement angle, shear web, 
frame outer chord and inner chord; a one-time inspection to detect 
missing fasteners; repetitive inspections of the cargo barrier net 
fitting for cracking; repetitive inspections for cracking of the 
stringer S-15L aft intercostal; and repair or corrective action if 
necessary. Since we issued AD 2012-12-05, we have received reports of 
additional cracking in locations not covered by the inspections in that 
AD. For certain airplanes, this proposed AD would add new repetitive 
inspections of certain areas of the frame inner chord, and applicable 
on-condition actions. We are proposing this AD to address the unsafe 
condition on these products.

DATES: We must receive comments on this proposed AD by September 29, 
2017.

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 NPRM, contact Boeing 
Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 
2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740; telephone 
562-797-1717; Internet https://www.myboeingfleet.com. You may view this 
referenced service information at the FAA, Transport Standards Branch, 
1601 Lind Avenue SW., Renton, WA. For information on the availability 
of this material at the FAA, call 425-227-1221. It is also available on 
the internet at http://www.regulations.gov by searching for and 
locating Docket No. FAA-2017-0774.

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-2017-
0774; 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: Galib Abumeri, Aerospace Engineer, 
Airframe Section, FAA, Los Angeles Aircraft Certification Office (ACO) 
Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-
627-5324; fax: 562-627-5210; email: [email protected].

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-2017-0774; 
Product Identifier 2017-NM-036-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://

[[Page 38638]]

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

    On June 4, 2012, we issued AD 2012-12-05, Amendment 39-17084 (77 FR 
36139, June 18, 2012) (``AD 2012-12-05''), for all The Boeing Company 
Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. AD 
2012-12-05 superseded AD 2004-09-09, Amendment 39-13598 (69 FR 23646, 
April 30, 2004); and AD 2009-16-14, Amendment 39-15987 (74 FR 38901, 
August 5, 2009). AD 2012-12-05 requires repetitive inspections for 
cracking under the stop fittings and intercostal flanges and for 
cracking of the intercostal web, attachment clips, stringer splice 
channels, frame, reinforcement angle, shear web, frame outer chord and 
inner chord; a one-time inspection to detect missing fasteners; 
repetitive inspections of the cargo barrier net fitting for cracking; 
repetitive inspections for cracking of the stringer S-15L aft 
intercostal; and repair or corrective action if necessary. AD 2012-12-
05 resulted from reports of cracking of the station (STA) 348.2 frame 
above the two outboard fasteners attaching the frame inner chord and 
door stop fittings, and in the outboard chord at stringer S-16L. AD 
2012-12-05 also resulted from reports of missing fasteners in the STA 
348.2 frame inner chord. We issued AD 2012-12-05 to detect and correct 
fatigue cracking of the intercostals on the forward and aft sides of 
the forward entry door cutout, which could result in loss of the 
forward entry door and rapid decompression of the airplane.

Actions Since AD 2012-12-05 Was Issued

    Since we issued AD 2012-12-05, we have received reports of 
additional cracking in the STA 351.2 frame inner chord at stringer S-
17L, at the fastener hole location common to the frame inner chord, 
door sill, and shear web. The cracks were reported on Model 737-300 and 
-500 airplanes that had accumulated between 40,600 and 65,500 total 
flight cycles. The STA 351.2 frame inner chord at stringer S-17L is 
hidden under the shear web and the door sill; therefore, any cracking 
at this location cannot be visually detected.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-53A1240, Revision 2, 
dated November 2, 2016. The service information describes procedures 
for, among other actions, repetitive inspections of the fastener holes 
in the STA 351.2 frame inner chord at stringer 17L, and applicable on-
condition actions. This service information is reasonably available 
because the interested parties have access to it through their normal 
course of business or by the means identified in the ADDRESSES section.

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 retain all requirements of AD 2012-12-05. 
Although this proposed AD does not explicitly restate the actions in 
Boeing Alert Service Bulletin 737-53A1240, Revision 1, dated June 29, 
2010, that are part of the requirements of AD 2012-12-05, this proposed 
AD would retain those requirements. Those requirements are referenced 
in the service information identified previously, which, in turn, is 
referenced in paragraph (p) of this proposed AD. Paragraph (p) of this 
proposed AD would require accomplishment of the actions identified as 
``RC'' (required for compliance) in the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1240, Revision 2, dated November 
2, 2016, except for any differences identified as exceptions in the 
regulatory text of this proposed AD.
    For information on the procedures and compliance times for Boeing 
Alert Service Bulletin 737-53A1240, Revision 2, dated November 2, 2016, 
see this service information at http://www.regulations.gov by searching 
for and locating Docket No. FAA-2017-0774.

Costs of Compliance

    We estimate that this proposed AD affects 411 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
            Action                   Labor cost         Parts cost    Cost per product   Cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
Inspections for cracking       18 work-hours x $85                $0  $1,530 per        $628,830 per inspection
 under the stop fittings and    per hour = $1,530                      inspection        cycle.
 intercostal flanges            per inspection cycle.                  cycle.
 [retained actions from AD
 2012-12-05] (411 airplanes).
Inspection of areas forward    2 work-hours x $85                  0  $170 per          $69,870 per inspection
 of the aft entry door          per hour = $170 per                    inspection        cycle.
 [retained actions from AD      inspection cycle.                      cycle.
 2012-12-05] (411 airplanes).
Inspection of areas aft of     1 work-hour x $85 per               0  $85 per           $34,935 per inspection
 the forward entry door         hour = $85 per                         inspection        cycle.
 [retained actions from AD      inspection cycle.                      cycle.
 2012-12-05] (411 airplanes).
Inspection for missing         1 work-hour x $85 per             476  $561............  $230,571.
 fasteners [retained actions    hour = $85.
 from AD 2012-12-05] (411
 airplanes).
Inspection of fastener holes   27 work[dash]hours x                0  $2,295 per        $367,200 per inspection
 (new proposed action) (160     $85 per hour =                         inspection        cycle.
 airplanes).                    $2,295 per                             cycle.
                                inspection cycle.
----------------------------------------------------------------------------------------------------------------

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

[[Page 38639]]



                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                   Action                                 Labor cost                Parts cost        product
----------------------------------------------------------------------------------------------------------------
Repair of cracking done in accordance with   24 work-hours x $85 per hour =              $11,856         $13,896
 Boeing Alert Service Bulletin 737-53A1240.   $2,040.
----------------------------------------------------------------------------------------------------------------

    We have received no definitive data that would enable us to provide 
cost estimates for the other on-condition corrective 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.
    This proposed AD is issued in accordance with authority delegated 
by the Executive Director, Aircraft Certification Service, as 
authorized by FAA Order 8000.51C. In accordance with that order, 
issuance of ADs is normally a function of the Compliance and 
Airworthiness Division, but during this transition period, the 
Executive Director has delegated the authority to issue ADs applicable 
to transport category airplanes to the Director of the System Oversight 
Division.

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 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),
    (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 removing Airworthiness Directive (AD) 
2012-12-05, Amendment 39-17084 (77 FR 36139, June 18, 2012), and adding 
the following new AD:

The Boeing Company: Docket No. FAA-2017-0774; Product Identifier 
2017-NM-036-AD.

(a) Comments Due Date

    The FAA must receive comments on this AD action by September 29, 
2017.

(b) Affected ADs

    This AD replaces AD 2012-12-05, Amendment 39-17084 (77 FR 36139, 
June 18, 2012) (``AD 2012-12-05'').

(c) Applicability

    This AD applies to all The Boeing Company Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes, certificated in any 
category.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of cracking of the station (STA) 
348.2 frame above the two outboard fasteners attaching the frame 
inner chord and door stop fittings, and in the outboard chord at 
stringer S-16L; missing fasteners in the STA 348.2 frame inner 
chord; and additional cracking in locations not covered by the 
inspections in AD 2012-12-05. We are issuing this AD to detect and 
correct fatigue cracking of the intercostals on the forward and aft 
sides of the forward entry door cutout, which could result in loss 
of the forward entry door and rapid decompression of the airplane.

(f) Compliance

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

(g) Retained Initial Compliance Time for Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes, With No Changes

    This paragraph restates the requirements of paragraph (i) of AD 
2012-12-05, with no changes. For all Model 737-100, -200, -200C, -
300, -400, and -500 series airplanes, as identified in Boeing Alert 
Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007: 
Before the accumulation of 15,000 total flight cycles, or within 
4,500 flight cycles after November 1, 2005 (the effective date of AD 
2005-20-03, Amendment 39-14296 (70 FR 56361, September 27, 2005) 
(``AD 2005-20-03'')), whichever occurs later: Do the inspections 
required by paragraphs (i) and (j) of this AD.

(h) Retained Initial Compliance Time for Model 737-200C Series 
Airplanes, With No Changes

    This paragraph restates the requirements of paragraph (j) of AD 
2012-12-05, with no changes. For all Model 737-200C series 
airplanes, as identified in Boeing Alert Service Bulletin 737-
53A1204, Revision 1, dated March 26, 2007: Before the accumulation 
of 15,000 total flight cycles, or within 4,500 flight cycles after 
September 9, 2009 (the effective date of AD 2009-16-14, Amendment 
39-15987 (74 FR 38901, August 5, 2009) (``AD 2009-16-14'')), 
whichever occurs later, do the inspection required by paragraph (k) 
of this AD.

(i) Retained Initial Inspection for Group 1 Configuration Airplanes, 
With No Changes

    This paragraph restates the requirements of paragraph (k) of AD 
2012-12-05, with no changes. For Group 1 airplanes identified in 
Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 
26, 2007: Perform a detailed inspection for cracking of the 
intercostal web, attachment clips, and stringer splice channels; and 
a high frequency eddy current (HFEC) inspection for cracking of the 
stringer splice channels located forward and aft of the forward 
entry door; and do all applicable corrective actions before further 
flight; in accordance with Parts

[[Page 38640]]

1 and 2 of the Work Instructions of Boeing Special Attention Service 
Bulletin 737-53-1204, dated June 19, 2003, or Boeing Alert Service 
Bulletin 737-53A1204, Revision 1, dated March 26, 2007; or in 
accordance with Parts 1, 2, 4, and 5 of the Work Instructions of 
Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 
24, 2010. After September 9, 2009 (the effective date of AD 2009-16-
14), and until July 23, 2012 (the effective date of AD 2012-12-05), 
Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 
26, 2007; or Boeing Alert Service Bulletin 737-53A1204, Revision 2, 
dated June 24, 2010; may be used to accomplish the actions required 
by this paragraph. As of July 23, 2012, only Boeing Alert Service 
Bulletin 737-53A1204, Revision 2, dated June 24, 2010, may be used 
to accomplish the actions required by this paragraph.

(j) Retained Initial Inspection for Cargo Configuration Airplanes 
(Forward of the Forward Entry Door), With No Changes

    This paragraph restates the requirements of paragraph (l) of AD 
2012-12-05, with no changes. For Group 2 cargo airplanes identified 
in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated 
March 26, 2007: Perform a detailed inspection for cracking of the 
intercostal webs and attachment clips located forward of the forward 
entry door, and do all applicable corrective actions before further 
flight, in accordance with Part 3 of the Work Instructions of Boeing 
Special Attention Service Bulletin 737-53-1204, dated June 19, 2003, 
or Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated 
March 26, 2007; or in accordance with Part 3 of Boeing Alert Service 
Bulletin 737-53A1204, Revision 2, dated June 24, 2010. After 
September 9, 2009 (the effective date of AD 2009-16-14), and until 
July 23, 2012 (the effective date of AD 2012-12-05), Boeing Alert 
Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007; or 
Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 
24, 2010; may be used to accomplish the actions required by this 
paragraph. As of July 23, 2012, only Boeing Alert Service Bulletin 
737-53A1204, Revision 2, dated June 24, 2010, may be used to 
accomplish the actions required by this paragraph.

(k) Retained Initial Inspection for Cargo Configuration Airplanes (Aft 
of the Forward Entry Door), With No Changes

    This paragraph restates the requirements of paragraph (m) of AD 
2012-12-05, with no changes. For Group 2 cargo airplanes identified 
in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated 
March 26, 2007: Perform a detailed inspection for cracking of the 
intercostal webs and attachment clips located aft of the forward 
entry door, and do all applicable corrective actions before further 
flight, in accordance with Part 4 of the Work Instructions of Boeing 
Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 
2007; or in accordance with Part 3 of Boeing Alert Service Bulletin 
737-53A1204, Revision 2, dated June 24, 2010. As of July 23, 2012 
(the effective date of AD 2012-12-05), only Boeing Alert Service 
Bulletin 737-53A1204, Revision 2, dated June 24, 2010, may be used 
to accomplish the actions required by this paragraph.

(l) Retained Repetitive Inspections, With No Changes

    This paragraph restates the requirements of paragraph (n) of AD 
2012-12-05, with no changes. Repeat the inspections required by 
paragraphs (i), (j), and (k) of this AD thereafter at intervals not 
to exceed 6,000 flight cycles after the previous inspection, or 
within 3,000 flight cycles after September 9, 2009, whichever occurs 
later.

(m) Retained Exceptions to Boeing Special Attention Service Bulletin 
737-53-1204, With No Changes

    This paragraph restates the requirements of paragraph (o) of AD 
2012-12-05, with no changes. Do the actions required by paragraphs 
(g), (h), (i), (j), (k), and (l) of this AD by accomplishing all the 
applicable actions specified in the Accomplishment Instructions of 
Boeing Special Attention Service Bulletin 737-53-1204, dated June 
19, 2003; Boeing Alert Service Bulletin 737-53A1204, Revision 1, 
dated March 26, 2007; or Boeing Alert Service Bulletin 737-53A1204, 
Revision 2, dated June 24, 2010; except as provided by paragraphs 
(m)(1) and (m)(2) of this AD. After September 9, 2009 (the effective 
date of AD 2009-16-14), and until July 23, 2012 (the effective date 
of AD 2012-12-05), Boeing Alert Service Bulletin 737-53A1204, 
Revision 1, dated March 26, 2007; or Boeing Alert Service Bulletin 
737-53A1204, Revision 2, dated June 24, 2010; may be used to 
accomplish the actions required by this paragraph. As of July 23, 
2012, only Boeing Alert Service Bulletin 737-53A1204, Revision 2, 
dated June 24, 2010, may be used to accomplish the actions required 
by this paragraph.
    (1) Where Boeing Special Attention Service Bulletin 737-53-1204, 
dated June 19, 2003; Boeing Alert Service Bulletin 737-53A1204, 
Revision 1, dated March 26, 2007; or Boeing Alert Service Bulletin 
737-53A1204, Revision 2, dated June 24, 2010, specifies to contact 
Boeing for repair instructions: Before further flight, repair using 
a method approved in accordance with the procedures specified in 
paragraph (s) of this AD.
    (2) Where Boeing Special Attention Service Bulletin 737-53-1204, 
dated June 19, 2003; or Boeing Alert Service Bulletin 737-53A1204, 
Revision 1, dated March 26, 2007; specifies a compliance time 
relative to the date of a service bulletin, this AD requires 
compliance relative to September 9, 2009 (the effective date of AD 
2009-16-14). Where Boeing Special Attention Service Bulletin 737-53-
1204, dated June 19, 2003; or Boeing Alert Service Bulletin 737-
53A1204, Revision 1, dated March 26, 2007; specifies a compliance 
time relative to the date of the initial release of a service 
bulletin, this AD requires compliance relative to November 1, 2005 
(the effective date of AD 2005-20-03).

(n) Retained Exceptions to Boeing Alert Service Bulletin 737-53A1204, 
With No Changes

    This paragraph restates exceptions to Boeing Alert Service 
Bulletin 737-53A1204 specified in paragraph (r) of AD 2012-12-05, 
with no changes.
    (1) The access and restoration instructions identified in the 
Work Instructions of Boeing Alert Service Bulletin 737-53A1204, 
Revision 2, dated June 24, 2010, are not required by this AD. 
Operators may perform those actions in accordance with approved 
maintenance procedures.
    (2) The use of Boeing Drawing 65-88700 is not allowed when 
accomplishing the actions required by this AD in accordance with the 
Work Instructions of Boeing Alert Service Bulletin 737-53A1204, 
Revision 2, dated June 24, 2010.

(o) Retained Initial and Repetitive Inspections of the S-15L Aft 
Intercostal and Cargo Barrier Net Fitting for Model 737-200C Series 
Airplanes, With No Changes

    This paragraph restates the requirements of paragraph (s) of AD 
2012-12-05, with no changes. For Group 2 airplanes identified in 
Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 
24, 2010: Before the accumulation of 15,000 total flight cycles, or 
within 4,500 flight cycles after July 23, 2012 (the effective date 
of AD 2012-12-05), whichever occurs later, do initial detailed and 
HFEC inspections for cracking of the S-15L aft intercostal between 
BS 348.2 and BS 360, and do a detailed inspection of the cargo 
barrier net fitting at the intercostal, in accordance with Figure 3 
of the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-53A1204, Revision 2, dated June 24, 2010. If any cracking is 
found, before further flight, repair using a method approved in 
accordance with the procedures specified in paragraph (s) of this 
AD. Repeat the inspections thereafter at intervals not to exceed 
6,000 flight cycles.

(p) Actions for Boeing Alert Service Bulletin 737-53A1240, Including 
New Repetitive Inspections of Certain Fastener Holes

    (1) For airplanes identified as Group 1 and Group 3 in Boeing 
Alert Service Bulletin 737-53A1240, Revision 2, dated November 2, 
2016: Except as required by paragraph (q) of this AD, at the 
applicable times specified in paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin 737-53A1240, Revision 2, dated 
November 2, 2016, do all applicable actions identified as ``RC'' 
(required for compliance) in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1240, Revision 2, dated November 2, 2016.
    (2) For airplanes identified as Group 2 in Boeing Alert Service 
Bulletin 737-53A1240, Revision 2, dated November 2, 2016: Within 120 
days after the effective date of this AD, do actions to correct the 
unsafe condition using a method approved in accordance with the 
procedures specified in paragraph (s) of this AD.

(q) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Service Bulletin 737-53A1240, Revision 2, 
dated November 2, 2016, uses the phrase ``after the Revision 2 date 
of this service bulletin,'' for purposes of determining compliance 
with the

[[Page 38641]]

requirements of this AD, the phrase ``after the effective date of 
this AD'' must be used.
    (2) Where Boeing Alert Service Bulletin 737-53A1240, Revision 2, 
dated November 2, 2016, specifies contacting Boeing, and specifies 
that action as RC: This AD requires using a method approved in 
accordance with the procedures specified in paragraph (s) of this 
AD.

(r) Credit for Previous Actions

    This paragraph provides credit for the actions specified in 
paragraph (p) of this AD, if those actions were performed before the 
effective date of this AD using Boeing Alert Service Bulletin 737-
53A1240, Revision 1, dated June 29, 2010, provided the conditions 
specified in paragraphs (r)(1) and (r)(2) of this AD are met and 
except as provided by paragraph (r)(3) of this AD. Boeing Alert 
Service Bulletin 737-53A1240, Revision 1, dated June 29, 2010, was 
incorporated by reference in AD 2012-12-05.
    (1) Note 1 of paragraph 3.A of the Accomplishment Instructions 
of Boeing Alert Service Bulletin 737-53A1240, Revision 1, dated June 
29, 2010, was disregarded when accomplishing the actions.
    (2) Boeing Drawing 65-88700 was not used when accomplishing the 
actions in accordance with the Work Instructions of Boeing Alert 
Service Bulletin 737-53A1240, Revision 1, dated June 29, 2010.
    (3) The access and restoration instructions identified in the 
Work Instructions of Boeing Alert Service Bulletin 737-53A1240, 
Revision 1, dated June 29, 2010, are not required. Operators are 
allowed to perform those actions in accordance with approved 
maintenance procedures.

(s) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles Aircraft Certification Office (ACO) 
Branch, 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 certification office, 
send it to the attention of the person identified in paragraph 
(t)(1) 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, modification, or alteration required by this AD 
if it is approved by the Boeing Commercial Airplanes Organization 
Designation Authorization (ODA) that has been authorized by the 
Manager, Los Angeles ACO Branch, to make those findings. To be 
approved, the repair method, modification deviation, or alteration 
deviation must meet the certification basis of the airplane, and the 
approval must specifically refer to this AD.
    (4) Except as required by paragraph (q)(2) of this AD: For 
service information that contains steps that are labeled as Required 
for Compliance (RC), the provisions of paragraphs (s)(4)(i) and 
(s)(4)(ii) of this AD apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. If a step or substep is labeled ``RC Exempt,'' then the 
RC requirement is removed from that step or substep. An AMOC is 
required for any deviations to RC steps, including substeps and 
identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(t) Related Information

    (1) For more information about this AD, contact Galib Abumeri, 
Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles 
Aircraft Certification Office (ACO) Branch, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5324; fax: 562-
627-5210; email: [email protected].
    (2) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Contractual & Data Services 
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740; 
telephone 562-797-1717; Internet https://www.myboeingfleet.com. You 
may view this referenced service information at the FAA, Transport 
Standards Branch, 1601 Lind Avenue SW., Renton, WA. For information 
on the availability of this material at the FAA, call 425-227-1221.

    Issued in Renton, Washington, on August 2, 2017.
Jeffrey E. Duven,
Director, System Oversight Division, Aircraft Certification Service.
[FR Doc. 2017-16776 Filed 8-14-17; 8:45 am]
 BILLING CODE 4910-13-P