
[Federal Register Volume 77, Number 89 (Tuesday, May 8, 2012)]
[Proposed Rules]
[Pages 26993-26996]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-11019]


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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]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain The Boeing Company Model 737-600, -700, -800, -900, and -900ER 
series airplanes. This proposed AD was prompted by reports that certain 
seat

[[Page 26994]]

track bolts were found with severed head bolts due to fatigue. This 
proposed AD would require 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 proposed AD 
also provides an optional terminating action for the repetitive 
inspections. We are proposing 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.

DATES: We must receive comments on this proposed AD by June 22, 2012.

ADDRESSES: You may send comments 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, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax 206-766-5680; email me.boecom@boeing.com; 
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: Patrick Gillespie, Aerospace Engineer, 
Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle 
Aircraft Certification Office (ACO), 1601 Lind Avenue SW., Renton, 
Washington 98057-3356; phone: 425-917-6429; fax: 425-917-6590; email: 
patrick.gillespie@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-2012-0426; 
Directorate Identifier 2011-NM-087-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 indicating that the seat track bolts at Station 
727B, buttock lines (BL) 24.75 and 45.50 left and right sides, were 
found with severed bolt heads due to fatigue. Missing or severed bolt 
heads, if not detected and 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.

Relevant Service Information

    We reviewed Boeing Special Attention Service Bulletin 737-53-1296, 
dated January 11, 2011. That service information describes procedures 
for 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.
    Related investigative action includes detailed inspection and high 
frequency eddy current (HFEC) inspections for cracking in holes common 
to the splice strap and forward seat track.
    Corrective actions include contacting Boeing for repair 
instructions, repairing, replacing missing or severed titanium seat 
track bolts with CRES bolts, and replacing a cracked splice strap with 
a new slice strap. Replacing the missing or severed seat track bolts 
and installing the new splice strap eliminates the need for the 
repetitive splice strap inspections at Station 727B, BL 24.75 and 
45.50, left and right sides, on all airplanes.
    For the inspections for cracking of the splice strap and forward 
seat track holes and replacement of missing or severed seat track 
bolts, the service information specifies an initial compliance time of 
before 7,000 total flight cycles or within 24 months after the issue 
date of the service bulletin, and a repetitive interval of 7,000 flight 
cycles.

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 these same type 
designs.

Proposed AD Requirements

    This proposed AD would require accomplishing the actions specified 
in the service information described previously, except as discussed 
below.

Differences Between Proposed AD and Service Bulletin

    Although Boeing Special Attention Service Bulletin 737-53-1296, 
dated January 11, 2011, specifies that operators may contact the 
manufacturer for disposition of certain repair conditions, this 
proposed AD would require operators to repair those conditions using a 
method approved by the FAA.
    Although Boeing Special Attention Service Bulletin 737-53-1296, 
dated January 11, 2011, specifies the sequence of steps performed in 
that service bulletin can be changed, this proposed AD would require 
operators to perform the repair using the sequence of steps in that 
service bulletin.

Costs of Compliance

    We estimate that this proposed AD affects 168 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

[[Page 26995]]



                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                       Cost per    Cost on U.S.
                Action                            Labor cost             Parts cost    product       operators
----------------------------------------------------------------------------------------------------------------
Replace bolts and install new splice    18 work-hours x $85 per hour =       $1,991       $3,521        $591,528
 strap.                                  $1,530.
Repetitive Inspection.................  3 work-hours x $85 per hour =             0          255          42,840
                                         $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 proposed 
AD.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would not 
have a substantial direct effect on the States, on the relationship 
between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

The Boeing Company: Docket No. FAA-2012-0426; Directorate Identifier 
2011-NM-087-AD.

(a) Comments Due Date

    We must receive comments by June 22, 2012.

(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.

(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 this paragraph: Before further flight, do a high frequency eddy 
current (HFEC) inspection for cracking in the fastener holes and do 
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 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.

(h) Detailed and High Frequency Eddy Current 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 in accordance with a method approved by the Manager, 
Seattle 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.

[[Page 26996]]

(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.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle 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 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

    (1) For more information about this AD, contact Patrick 
Gillespie, Aerospace Engineer, Cabin Safety and Environmental 
Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue SW., Renton, Washington 98057-3356; phone: 
425-917-6429; fax: 425-917-6590; email: patrick.gillespie@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, Washington 98124-2207; telephone 
206-544-5000, extension 1; fax 206-766-5680; email 
me.boecom@boeing.com; 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 April 29, 2012.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-11019 Filed 5-7-12; 8:45 am]
BILLING CODE 4910-13-P


