
[Federal Register Volume 78, Number 221 (Friday, November 15, 2013)]
[Rules and Regulations]
[Pages 68693-68697]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-27091]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2012-0426; Directorate Identifier 2011-NM-087-AD; 
Amendment 39-17659; AD 2013-23-04]
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 737-600, -700, -800, -900, and -900ER series 
airplanes. This AD was prompted by reports that certain seat track 
bolts were found with severed head bolts due to fatigue. This AD 
requires replacing titanium seat track bolts with corrosion resistant 
steel (CRES) bolts, repetitive inspections for cracking of the splice 
strap and forward seat track holes, and related investigative and 
corrective actions if necessary. This AD also provides an optional 
terminating action for the repetitive inspections. We are issuing this 
AD to detect and correct missing or severed bolt heads, which, if not 
corrected, could result in the inability of the seat track to carry 
passenger loads, which could cause the seats to detach from the seat 
track, resulting in possible injury to passengers during an emergency 
landing or survivable crash.

DATES: This AD is effective December 20, 2013.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of December 20, 
2013.

ADDRESSES: For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, Washington 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, 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

[[Page 68694]]

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 Document Management Facility, U.S. Department 
of Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Sarah Piccola, Aerospace Engineer, 
Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle 
Aircraft Certification Office (ACO), 1601 Lind Avenue SW., Renton, WA 
98057-3356; phone: 425-917-6483; fax: 425-917-6590; email: 
sarah.piccola@faa.gov.

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an AD that would apply to the specified products. 
The NPRM published in the Federal Register on May 8, 2012 (77 FR 
26993). The NPRM proposed to require replacing titanium seat track 
bolts with CRES bolts, repetitive inspections for cracking of the 
splice strap and forward seat track holes, and related investigative 
and corrective actions if necessary. The NPRM also proposed to provide 
an optional terminating action for the repetitive inspections.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
(77 FR 26993, May 8, 2012), and the FAA's response to each comment. 
Boeing and United Airlines supported the NPRM.

Request To Revise Costs of Compliance Section

    American Airlines (American) requested that we revise the Costs of 
Compliance section of the NPRM (77 FR 26993, May 8, 2012). American 
explained that, since it alone operates 113 airplanes that are affected 
by the NPRM, several hundred airplanes should be affected.
    We agree with the request to revise the Costs of Compliance section 
of this final rule because there was an error in the number of affected 
airplanes identified in the Costs of Compliance section of NPRM (77 FR 
26993, May 8, 2012). We have updated the number of airplanes from 168 
to 973 in the Costs of Compliance section of this final rule 
accordingly.
    Although we have revised the cost calculation, there is no change 
to the actual number of airplanes affected by this final rule. This 
final rule refers to Boeing Special Attention Service Bulletin 737-53-
1296, dated January 11, 2011, for affected airplanes. The effectivity 
of Boeing Special Attention Service Bulletin 737-53-1296, dated January 
11, 2011, is correct. The number of affected airplanes identified in 
the Costs of Compliance section of this final rule now reflects the 
number of airplanes of U.S. registry listed in the effectivity of 
Boeing Special Attention Service Bulletin 737-53-1296, dated January 
11, 2011.

Request To Revise Compliance Time

    American requested that we revise the initial compliance time for 
replacing titanium seat track bolts with CRES bolts from 7,000 total 
flight cycles or within 24 months, to 8,000 total flight cycles or 
within 60 months (whichever occurs later) after the effective date of 
this AD. American stated that extending this compliance time would 
enable operators who have extended their maintenance program in 
accordance with Boeing maintenance planning documents to accomplish the 
replacement during the first heavy maintenance visit.
    American also asked that, if the compliance time cannot be extended 
for all airplanes, then the compliance time should be extended for 
certain airplanes. For example, American has found and replaced sheared 
bolts with new bolts on airplanes having between 13,000 and 15,000 
total flight cycles. Therefore, American concluded that the inspection 
interval could be extended to 7,000 flight cycles from ``bolt 
replacement'' for airplanes for which maintenance records show the seat 
track bolts were replaced previously. In addition, American stated that 
the fact it is finding and replacing severed seat track bolts proves 
that this condition will be detected and corrected by operators during 
routine maintenance.
    We disagree with extending the initial compliance time to 8,000 
total flight cycles or 60 months. The inspection threshold of 7,000 
total flight cycles was established by the manufacturer at 
approximately 90 percent of fatigue life. In developing an appropriate 
compliance time for this action, we considered the manufacturer's 
recommendation, the safety implications, parts availability, and 
maintenance schedules for the timely accomplishment of the inspection.
    Affected operators may request approval of an alternative method of 
compliance (AMOC) for an extension of the compliance times under the 
provisions of paragraph (j) of this final rule by submitting data 
substantiating that the change would provide an acceptable level of 
safety. We have not changed the final rule in regard to this issue.

Request To Allow Re-Sequencing of Steps

    American requested that we remove or reword the Differences Between 
Proposed AD and Service Bulletin section of the preamble of the NPRM 
(77 FR 26993, May 8, 2012) regarding the sentence that refers to the 
sequence of the steps in Boeing Special Attention Service Bulletin 737-
53-1296, dated January 11, 2011. American stated that the sentence 
specifies operators would be required to perform the repair using the 
sequence of steps in Boeing Special Attention Service Bulletin 737-53-
1296, dated January 11, 2011. American stated that this language is 
``ambiguous'' as no sections or figures in that service bulletin are 
titled ``Repair.'' Therefore, it is unclear if the NPRM refers to the 
entire service bulletin or only one portion.
    American stated that the sequence of removing and installing bolts, 
angles, or splice straps from the right side before the left side (or 
from forward to aft instead of aft to forward) has no impact on safety 
as long as the final installation of all parts is done in accordance 
with Boeing Special Attention Service Bulletin 737-53-1296, dated 
January 11, 2011. American requested that this exception to Boeing 
Special Attention Service Bulletin 737-53-1296, dated January 11, 2011, 
be removed or, at a minimum, re-worded to specifically state which 
sections must be accomplished in the sequence specified in Boeing 
Special Attention Service Bulletin 737-53-1296, dated January 11, 2011.
    We agree that clarification is necessary. Note 1. in paragraph 
3.A., ``General Information,'' of Boeing Special Attention Service 
Bulletin 737-53-1296, dated January 11, 2011, specifies that ``the 
instructions identified in Paragraph 3.B., Work Instructions, and the 
Figure(s) give the recommended sequence of steps. The sequence of steps 
to do this service bulletin can be changed.'' We agree that 
accomplishing the left side before the right side or accomplishing 
forward before aft does not have an impact on safety.
    However, Note 1. in paragraph 3.A., ``General Information'' of 
Boeing Special Attention Service Bulletin 737-53-1296, dated January 
11, 2011, suggests this applies to the sequence of steps in

[[Page 68695]]

the figure(s), which clearly state ``in accordance with,'' in the 
Accomplishment Instructions. When the words ``in accordance with'' are 
included in a step in the Accomplishment Instructions, the operator 
must follow the corresponding sequence of steps that are provided. For 
example, if a step specifies to do a replacement ``in accordance with 
Figure 1,'' then the steps within Figure 1 must be done in sequence. 
This final rule does not dictate the order in which other steps are 
performed.

Statement Regarding Installation of Winglets

    Aviation Partners Boeing (APB) stated that the installation of 
winglets per supplemental type certificate (STC) ST00830SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/408E012E008616A7862578880060456C?OpenDocument&Highlight=st00830se) does 
not affect the actions specified in the NPRM (77 FR 26993, May 8, 
2012).
    We concur. STC ST00830SE does not affect the ability to accomplish 
the actions required by this final rule. Therefore, for airplanes on 
which STC ST00830SE is installed, a ``change in product'' alternative 
method of compliance (AMOC) approval request is not necessary to comply 
with the requirements of section 39.17 of the Federal Aviation 
Regulations (14 CFR 39.17).

Request To Include Note Regarding Access

    American requested the following note be added to the NPRM (77 FR 
26993, May 8, 2012): ``If it is necessary to remove more parts for 
access, you can remove those parts. If you can get access without 
removing identified parts, it is not necessary to remove all of the 
identified parts. Jacking and shoring limitations must be observed.'' 
American stated that this general information note is needed to remove 
the ambiguity relating to access required to accomplish the service 
information, and that it would provide operators additional 
flexibility.
    We agree that clarification is necessary. This general information 
note was one recently added to Boeing service information to remove the 
ambiguity. However, Boeing Special Attention Service Bulletin 737-53-
1296, dated January 11, 2011, does not contain this note. We 
acknowledge this information is helpful to remove the ambiguity related 
to access required to accomplish the actions specified in Boeing 
Special Attention Service Bulletin 737-53-1296, dated January 11, 2011. 
We have added similar information in paragraph (g) of this final rule.

Request To Revise Paragraphs (g) and (h)(2) of the NPRM (77 FR 26993, 
May 8, 2012)

    AirTran/Southwest Airlines (AirTran/Southwest) requested that we 
revise the wording in paragraphs (g) and (h)(2) of the NPRM (77 FR 
26993, May 8, 2012) that reads ``. . . repair in accordance with a 
method approved by the Manager, Seattle Aircraft Certification Office 
(ACO), FAA. 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'' to ``. . . repair the seat track using 
a method approved in accordance with the procedures specified in 
paragraph (j) of this AD.'' Southwest stated that this change would 
allow the ACO or Boeing Commercial Airplanes Organization Designation 
Authorization (ODA) to approve the repair.
    We agree. Paragraph (j)(3) of this AD already allows Boeing 
Commercial Airplanes ODA to approve repairs if authorized by the 
Seattle ACO. We have changed paragraphs (g) and (h)(2) of this final 
rule to refer to paragraph (j) of this final rule, as requested by the 
commenter.

Request To Clarify Installation Location in Paragraphs (g) and (h)(2) 
of the NPRM (77 FR 26993, May 8, 2012)

    AirTran/Southwest requested a note be added to paragraph (i) of the 
NPRM (77 FR 26993, May 8, 2012) to clarify the location of a splice 
strap installation. The commenter noted an error in Boeing Special 
Attention Service Bulletin 737-53-1296, dated January 11, 2011, in Step 
1, ``Move,'' of Figure 10, Sheet 5 of 7; and in Step 1, ``Move,'' of 
Figure 12, Sheet 5 of 7. AirTran/Southwest stated the splice strap 
needs to be centered with left buttock line (LBL) 45.50 and right 
buttock line (RBL) 45.50, respectively--not LBL 24.75.
    We agree that clarification is necessary. The errors noted by 
AirTran/Southwest are present in Boeing Special Attention Service 
Bulletin 737-53-1296, dated January 11, 2011. We acknowledge that the 
splice strap needs to be centered with LBL 45.50 and RBL 45.50, 
respectively--not LBL 24.75. Therefore, we have added Note 1 to 
paragraph (i) of this AD to clarify the location of a splice strap 
installation.

Request To Delay Issuance of AD

    AirTran/Southwest requested a delay in the issuance of this final 
rule until Boeing has had time to build up an adequate stock of seat 
track bolt and splice part kits when frame replacements are required. 
The commenter stated that Boeing currently has no kits in stock and has 
a reorder time of 558 days. AirTran/Southwest stated that there would 
be an economic and operational impact if Boeing has no stock of seat 
track bolt and splice kits, or if it takes Boeing 558 days to re-stock 
a kit.
    We disagree with the request to delay release of this final rule. 
Boeing has confirmed that the required kits are available to support of 
the compliance times specified in this final rule. Should adequate 
parts not be available approaching the end of the compliance period, 
paragraph (j) of this final rule provides operators the opportunity to 
request approval of an alternative compliance time if data are 
presented that prove the alternative compliance time will provide an 
acceptable level of safety. 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 changes:
     [Agr]re consistent with the intent that was proposed in 
the NPRM (77 FR 26993, May 8, 2012), for correcting the unsafe 
condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM (77 FR 26993, May 8, 2012).
    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 973 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

[[Page 68696]]



                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
               Action                         Labor cost            Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Replacement of bolts and             18 work-hours x $85 per              $1,991          $3,521      $3,425,933
 installation of new splice strap.    hour = $1,530.
Repetitive inspection..............  3 work-hours x $85 per hour               0             255         248,115
                                      = $255.
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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 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

    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):

2013-23-04 The Boeing Company: Amendment 39-17659; Docket No. FAA-
2012-0426; Directorate Identifier 2011-NM-087-AD.

(a) Effective Date

    This AD is effective December 20, 2013.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-600, -700, -800, 
-900, and -900ER series airplanes, with passenger seats installed; 
certificated in any category; as identified in Boeing Special 
Attention Service Bulletin 737-53-1296, dated January 11, 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 that certain seat track bolts 
were found with severed bolt heads due to fatigue. We are issuing 
this AD to detect and correct missing or severed bolt heads, which, 
if not corrected, could result in the inability of the seat track to 
carry passenger loads, which could cause the seats to detach from 
the seat track, resulting in possible injury to passengers during an 
emergency landing or survivable crash.

(f) Compliance

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

(g) Seat Track Bolt Replacement and Splice Strap Installation

    Before the accumulation of 7,000 total flight cycles, or within 
24 months after the effective date of this AD, whichever occurs 
later: Replace titanium seat track bolts with corrosion resistant 
steel (CRES) bolts at both the left and right sides of buttock lines 
24.75 and 45.50, in accordance with the Accomplishment Instructions 
of Boeing Special Attention Service Bulletin 737-53-1296, dated 
January 11, 2011. If a titanium seat track bolt is found missing 
from the structure during the accomplishment of the tasks required 
by paragraph (g) of this AD: Before further flight, do a high 
frequency eddy current (HFEC) inspection for cracking in the 
fastener holes and a general visual inspection of the area, 
including the splice strap and forward seat track for damage, and 
replace missing bolts with new or serviceable CRES bolts, in 
accordance with the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-53-1296, dated January 11, 2011. If 
cracking or damage is found: Before further flight, repair the seat 
track using a method approved in accordance with the procedures 
specified in paragraph (j) of this AD. If it is necessary to remove 
more parts for access, those parts may be removed. If access can be 
obtained without removing identified parts, it is not necessary to 
remove all identified parts. Jacking and shoring limitations should 
be observed.

(h) Detailed and HFEC Inspections

    Before the accumulation of 7,000 total flight cycles, or within 
24 months after the effective date of this AD, whichever occurs 
later: Do a detailed inspection and an HFEC inspection for cracking 
in the holes common to the splice strap and forward seat track at 
both the left and right sides of buttock lines 24.75 and 45.50, in 
accordance with the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-53-1296, dated January 11, 2011. 
Repeat the inspections thereafter at intervals not to exceed 7,000 
flight cycles, until the actions specified in paragraph (i) of this 
AD have been done.
    (1) If a crack is found in the splice strap during any 
inspection required by paragraph (h) of this AD: Before further 
flight, replace the seat track bolts and install a new splice strap 
part number (P/N) 146A5342-26 and retained angle at the affected 
location, in accordance with the Accomplishment Instructions of 
Boeing Special Attention Service Bulletin 737-53-1296, dated January 
11, 2011.
    (2) If a crack is found in the seat track during any inspection 
required by paragraph (h) of this AD, and Boeing Special Attention 
Service Bulletin 737-53-1296, dated January 11, 2011, specifies to 
contact Boeing for appropriate action: Before further flight, repair 
the seat track using a method approved

[[Page 68697]]

in accordance with the procedures specified in paragraph (j) of this 
AD.

(i) Optional Terminating Action

    Replacing the titanium seat track bolts with CRES bolts on both 
the left and right sides of buttock lines 24.75 and 45.50 at station 
727B, and installing a new splice strap P/N 146A5342-26, in 
accordance with the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-53-1296, dated January 11, 2011, 
terminates the repetitive inspections required by paragraph (h) of 
this AD.

    Note 1 to paragraph (i) of this AD: Boeing Special Attention 
Service Bulletin 737-53-1296, dated January 11, 2011, contains an 
error in Step 1, ``Move,'' of Figure 10, Sheet 5 of 7; and in Step 
1, ``Move,'' of Figure 12, Sheet 5 of 7. The splice strap needs to 
be centered with left buttock line 45.50 and right buttock line 
45.50, respectively-- not left buttock line 24.75, as stated in that 
service bulletin.

(j) 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 (k) 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 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.

(k) Related Information

    For more information about this AD, contact Sarah Piccola, 
Aerospace Engineer, Cabin Safety and Environmental Systems Branch, 
ANM-150S, FAA, Seattle Aircraft Certification Office (ACO), 1601 
Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6483; fax: 
425-917-6590; email: sarah.piccola@faa.gov.

(l) 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 Special Attention Service Bulletin 737-53-1296, dated 
January 11, 2011.
    (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, Washington 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, Transport 
Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington. 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 November 4, 2013.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-27091 Filed 11-14-13; 8:45 am]
BILLING CODE 4910-13-P


