[Federal Register Volume 78, Number 45 (Thursday, March 7, 2013)]
[Proposed Rules]
[Pages 14734-14737]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-05328]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2012-0268; Directorate Identifier 2011-NM-129-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Supplemental notice of proposed rulemaking (NPRM); reopening of 
comment period.

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SUMMARY: We are revising an earlier proposed airworthiness directive 
(AD) for certain The Boeing Company Model 737-600, -700, -700C, -800, -
900 and -900ER series airplanes. That NPRM proposed to require 
inspecting for a serial number that starts with the letters ``SAIC'' on 
the left- and right-side horizontal stabilizer identification plate; a 
detailed inspection for correct bolt protrusion and chamfer of the 
termination fitting bolts of the horizontal stabilizer rear spar, if 
necessary; inspecting to determine if certain bolts are installed, if 
necessary; and doing related investigative and corrective actions if 
necessary. That NPRM was prompted by reports of incorrectly installed 
bolts common to the rear spar termination fitting on the horizontal 
stabilizer. This action revises that NPRM by adding airplanes to the 
applicability. We are proposing this supplemental NPRM to prevent loss 
of structural integrity of the horizontal stabilizer attachment and 
loss of control of the airplane. Since these actions impose an 
additional burden over that proposed in the NPRM, we are reopening the 
comment period to allow the public the chance to comment on these 
proposed changes.

DATES: We must receive comments on this supplemental NPRM by April 22, 
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: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590, 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; 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: Nancy Marsh, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue SW., Renton, Washington 98057-3356; phone: 425-
917-6440; fax: 425-917-6590; 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-2012-0268; 
Directorate Identifier 2011-NM-129-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 issued an NPRM to amend 14 CFR part 39 to include an AD that 
would apply to certain The Boeing Company Model 737-600, -700, -700C, -
800, and -900 series airplanes. That NPRM published in the Federal 
Register on March 20, 2012 (77 FR 16188). That NPRM proposed to require 
inspecting for a serial number that starts with the letters ``SAIC'' on 
the left- and right-side horizontal stabilizer identification plate; a 
detailed inspection for correct bolt protrusion and chamfer of the 
termination fitting bolts of the horizontal stabilizer rear spar, if 
necessary; inspecting to determine if certain bolts are installed, if 
necessary; and doing related investigative and corrective actions if 
necessary.

Actions Since Previous NPRM (77 FR 16188, March 20, 2012) Was Issued

    Since we issued the previous NPRM (77 FR 16188, March 20, 2012), we 
have determined that horizontal stabilizers are frequently rotated on 
the fleet and could be installed on any Model 737-600, -700, -700C, -
800, and -900 airplane, including airplanes outside the applicability 
of the NPRM. Therefore, we have determined that the identified unsafe 
condition may exist on all Model 737-600, -700, -700C, -800, -900, and 
-900ER series airplanes.

Comments

    We gave the public the opportunity to comment on the previous NPRM 
(77 FR 16188, March 20, 2012). The following presents the comments 
received on the NPRM and the FAA's response to each comment.

Support for the Previous NPRM (77 FR 16188, March 20, 2012)

    United Airlines stated it supports the previous NPRM (77 FR 16188, 
March 20, 2012).

[[Page 14735]]

Request To Revise Applicability

    Southwest Airlines (Southwest) requested that we revise the 
applicability of the previous NPRM (77 FR 16188, March 20, 2012). 
Southwest suggested revising the applicability of the NPRM to identify 
serial numbers of the affected horizontal stabilizers, or to open the 
applicability of the NPRM to all airplanes, since the applicability 
listed in the previous NPRM and the effectivity of the service 
information do not account for horizontal stabilizers interchanged 
between airplanes.
    We agree with the commenter's request for the reasons described in 
``Actions Since Previous NPRM (77 FR 16188, March 20, 2012) was 
Issued.'' We have revised paragraph (c) of this supplemental NPRM to 
include all The Boeing Company Model 737-600, -700, -700C, -800, -900, 
and -900ER series airplanes, because the horizontal stabilizers can be 
rotated among airplanes. This change has been coordinated with Boeing.
    We also have added new paragraph (k) to this supplemental NPRM (and 
re-identified subsequent paragraphs) to prohibit installation of a 
horizontal stabilizer on any airplane included in the applicability of 
this AD unless the horizontal stabilizer has been inspected and 
applicable corrective actions have been done and no incorrect bolt 
protrusion and no incorrect chamfer of the termination fitting 
fasteners have been found.

Request To Improve Inspection Procedures

    Southwest and TUIfly Fluggesellschaft mbH requested we revise the 
previous NPRM (77 FR 16188, March 20, 2012) to permit operators to 
demonstrate compliance for inspecting the horizontal stabilizer to 
determine the serial number by means of a review of the manufacturer's 
delivery documentation for the accomplishment of Boeing Service 
Bulletin 737-55-1090, dated March 30, 2011. TUIfly Fluggesellschaft 
said that the delivery paperwork received with the airplane includes 
the serial number of the stabilizers installed on the airplane at the 
time of delivery.
    We agree that the manufacturer's delivery documentation identifies 
the serial number of the horizontal stabilizer assembly installed on 
the airplane at the time of delivery. However, as discussed in the 
previous comment, horizontal stabilizers are rotable parts, so in 
addition to the delivery records, the airplane maintenance records must 
also be used to positively identify the current stabilizer installed on 
the airplane. We have added wording to paragraph (g) of this 
supplemental NPRM to state that a review of manufacturer delivery and 
operator maintenance records is acceptable if that review conclusively 
determines the serial number of the horizontal stabilizer.

STC Winglet Comment

    Aviation Partners Boeing stated that the installation of winglets 
per Supplemental Type Certificate (STC) ST00830SE does not affect 
accomplishment of the proposed requirements.
    We have added paragraph (c)(2) to this supplemental NPRM to state 
that installation of STC ST00830SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/408E012E008616A7862578880060456C?OpenDocument&Highlight=st00830se) does 
not affect the ability to accomplish the actions proposed by this 
supplemental NPRM. 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). For all other AMOC requests, the operator must request 
approval of an AMOC in accordance with the procedures specified in 
paragraph (l) of this supplemental NPRM.

Request To Revise Applicability To Include Bolt Type BACB30XL

    American Airlines (American) requested that the inspections and 
corrective actions specified in Boeing Service Bulletin 737-55-1090, 
dated March 30, 2011, be used to address the inspections and corrective 
actions for the alternative bolt type part number (P/N) BACB30XL that 
may be installed at the same locations as bolt type P/N BACB30US14K() 
or BACB30US16K(). American indicated the existing service information 
does not provide corrective actions for the alternative bolt type P/N 
BACB30XL that may be installed in the locations requiring bolt 
inspection.
    We disagree with the request because Boeing Service Bulletin 737-
55-1090, dated March 30, 2011, provides specific inspection criteria 
and measurements that are applicable only to the bolt type P/N 
BACB30US. Those criteria cannot be directly applied to the alternative 
bolt types. The manufacturer plans to revise that service bulletin to 
include corrective actions for the alternative bolt type P/N BACB30XL. 
We will review the service bulletin and may approve the revised service 
instructions as an AMOC to the AD, when the revised service bulletin is 
available. We have not changed the supplemental NPRM in this regard.

Request To Allow Alternative Service Information

    Oman Air (Oman) requested that credit for prior accomplishment of 
Boeing Service Letters 737-SL-55-027, dated April 12, 2007, and 737-SL-
55-028, dated April 26, 2007, be given as an alternative to the 
accomplishment of the inspections and corrective actions specified in 
Boeing Service Bulletin 737-55-1090, dated March 30, 2011, which are 
required by paragraphs (g), (h), and (k) of the previous NPRM (77 FR 
16188, March 20, 2012).
    We disagree. Boeing Service Letter 737-SL-55-027, dated April 12, 
2007, and Boeing Service Letter 737-SL-55-028, dated April 26, 2007, 
were published prior to the identification of the safety issues created 
by the missing washers. Although these service letters provide 
instructions for the replacement of any missing washers, they do not 
address the potential durability issues created by the unclamped joint 
that are addressed by the repetitive inspections of the structure, as 
specified in Boeing Service Bulletin 737-55-1090, dated March 30, 2011. 
The commenter did not provide any data to substantiate the durability 
of the corrective actions specified in those service letters. This 
proposal could be considered if data were provided to substantiate the 
request, using the procedures defined in paragraph (l) of this 
supplemental NPRM for requesting approval of an AMOC. We have not 
changed the supplemental NPRM in this regard.

Revision to Service Bulletin

    The Boeing Company (Boeing) stated it will revise Boeing Service 
Bulletin 737-55-1090, dated March 30, 2011, to instruct operators to 
inspect for bolt types other than BACB30US, to provide repair methods 
for bolt configurations other than BACB30US, and to revise Figure 1 of 
that service bulletin to correctly identify the serial number location 
in lieu of the part number location.
    Boeing did not request a specific change to the previous NPRM (77 
FR 16188, March 20, 2012). We already specified the correct location of 
the serial number in paragraph (j) of the previous NPRM. We also 
already specified that an inspection for bolt types other than part 
number BACB30US14K() or BACB30US16K() is required for paragraph (g) of 
the previous NPRM.

[[Page 14736]]

FAA's Determination

    We are proposing this supplemental NPRM 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. Certain changes described above expand the scope of 
the original NPRM (77 FR 16188, March 20, 2012). As a result, we have 
determined that it is necessary to reopen the comment period to provide 
additional opportunity for the public to comment on this supplemental 
NPRM.

Proposed Requirements of the Supplemental NPRM

    This supplemental NPRM would require inspecting for a serial number 
that starts with the letters ``SAIC'' on the left- and right-side 
horizontal stabilizer identification plate; a detailed inspection for 
correct bolt protrusion and chamfer of the termination fitting bolts of 
the horizontal stabilizer rear spar, if necessary; inspecting to 
determine if certain bolts are installed, if necessary; and doing 
related investigative and corrective actions if necessary.

Costs of Compliance

    We estimate that this proposed AD affects 1,147 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
               Action                         Labor cost            Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Inspection.........................  1 work-hour x $85 per hour               $0             $85         $97,495
                                      = $85 per inspection cycle.
Replacement of bolts...............  17 work-hours x $85 per               1,530           2,975       3,412,325
                                      hour = $1,445.
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    We have received no definitive data that would enable us to provide 
a cost estimate for the on-condition actions (contacting Boeing and 
repairing cracks or damage) specified in this supplemental NPRM.
    According to the manufacturer, some of the costs of this proposed 
AD may be covered under warranty, thereby reducing the cost impact on 
affected individuals. We do not control warranty coverage for affected 
individuals. As a result, we have included all costs in our cost 
estimate.

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-2012-0268; Directorate Identifier 
2011-NM-129-AD.

(a) Comments Due Date

    We must receive comments by April 22, 2013.

(b) Affected ADs

    None.

(c) Applicability

    (1) This AD applies to all The Boeing Company Model 737-600, -
700, -700C, -800, -900, and -900ER series airplanes, certificated in 
any category.
    (2) Installation of Supplemental Type Certificate (STC) 
ST00830SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/408E012E008616A7862578880060456C?OpenDocument&Highlight=st00830se) 
does not affect the ability to accomplish the actions required by 
this AD. 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 14 CFR 39.17.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 55: Stabilizer.

(e) Unsafe Condition

    This AD was prompted by reports of incorrectly installed bolts 
common to the rear spar termination fitting of the horizontal 
stabilizer. We are issuing this AD to prevent loss of structural 
integrity of the horizontal stabilizer attachment and loss of 
control of the airplane.

(f) Compliance

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

(g) Inspecting the Horizontal Stabilizer and Corrective Actions

    Except as provided by paragraph (i) of this AD, at the 
applicable times specified in paragraph 1.E., ``Compliance,'' of 
Boeing Service Bulletin 737-55-1090, dated March

[[Page 14737]]

30, 2011: Do an inspection for a serial number that starts with the 
letters ``SAIC'' on the identification plates of the left- and 
right-side horizontal stabilizers, in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 737-55-1090, 
dated March 30, 2011. A review of manufacturer delivery and operator 
maintenance records is acceptable to make the determination 
specified in this paragraph if the serial number can be conclusively 
identified from that review.
    (1) If a serial number starting with the letters ``SAIC'' is 
found on a horizontal stabilizer identification plate: Except as 
provided by paragraph (i) of this AD, at the applicable times 
specified in paragraph 1.E., ``Compliance,'' of Boeing Service 
Bulletin 737-55-1090, dated March 30, 2011, do a detailed inspection 
for correct bolt protrusion and correct chamfer of the termination 
fitting bolts of the horizontal stabilizer rear spar, in accordance 
with the Accomplishment Instructions of Boeing Service Bulletin 737-
55-1090, dated March 30, 2011. Concurrently with the detailed 
inspection, inspect to determine if bolts other than part number (P/
N) BACB30US14K() or BACB30US16K(), as applicable, are installed. 
Before further flight, do all applicable related investigative and 
corrective actions, in accordance with the Accomplishment 
Instructions of Boeing Service Bulletin 737-55-1090, dated March 30, 
2011.
    (2) If no SAIC serial number is found, no further action is 
required by this AD.

(h) High Frequency Eddy Current (HFEC) and Ultrasonic Inspections of 
Termination Fitting and Repair

    For any location where a new bolt having a P/N BACB30US14K() is 
installed due to damage found during any inspection required by 
paragraph (g) of this AD: Except as provided by paragraph (i) of 
this AD, at the times specified in paragraph 1.E., ``Compliance,'' 
of Boeing Service Bulletin 737-55-1090, dated March 30, 2011, do 
HFEC and ultrasonic inspections for cracking of the forward and aft 
sides of the termination fitting, in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 737-55-1090, 
dated March 30, 2011. If any crack is found in any termination 
fitting: Before further flight, repair in accordance with the 
procedures specified in paragraph (l) of this AD. Repeat the HFEC 
and ultrasonic inspections thereafter at intervals not to exceed 
3,500 flight cycles.

(i) Exception to Compliance Time

    Where Boeing Service Bulletin 737-55-1090, dated March 30, 2011, 
specifies a compliance time ``after the original issue date on the 
service bulletin,'' this AD requires compliance within the specified 
compliance time after the effective date of this AD.

(j) Exceptions to Service Bulletin

    (1) Where Figure 1 of Boeing Service Bulletin 737-55-1090, dated 
March 30, 2011, points to the location of a part number rather than 
the serial number, this AD requires an inspection for an 
identification plate with a serial number that starts with the 
letters ``SAIC.''
    (2) If, during any inspection required by paragraphs (g) and (h) 
of this AD, any bolt other than P/N BACB30US14K() or BACB30US16K(), 
as applicable, is found: Before further flight, repair using a 
method approved in accordance with the procedures specified in 
paragraph (l) of this AD.

(k) Parts Installation Limitation

    As of the effective date of this AD, no person may install a 
horizontal stabilizer on any airplane included in the applicability 
of this AD unless it has been inspected and any applicable 
corrective actions done using the procedures specified in paragraph 
(g) of this AD.

(l) 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: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD if it is approved by the 
Boeing Commercial Airplanes Organization Designation Authorization 
(ODA) that has been authorized by the Manager, Seattle ACO, to make 
those findings. For a repair method to be approved, the repair must 
meet the certification basis of the airplane, and the approval must 
specifically refer to this AD.

(m) Related Information

    (1) For more information about this AD, contact Nancy Marsh, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office (ACO), 1601 Lind Avenue SW., Renton, Washington 
98057-3356; phone: 425-917-6440; fax: 425-917-6590; email: 
[email protected].
    (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; 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 February 26, 2013.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-05328 Filed 3-6-13; 8:45 am]
BILLING CODE 4910-13-P