
[Federal Register Volume 77, Number 54 (Tuesday, March 20, 2012)]
[Proposed Rules]
[Pages 16188-16191]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-6628]


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

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: Notice of proposed rulemaking (NPRM).

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

SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain The Boeing Company Model 737-600, -700, -700C, -800, and -900 
series airplanes. This proposed AD was prompted by reports of 
incorrectly installed bolts common to the rear spar termination fitting 
on the horizontal stabilizer. This proposed AD 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 related investigative and corrective actions if necessary. This 
proposed AD would also require

[[Page 16189]]

repetitive inspections for cracking of the termination fitting at 
certain bolt locations, and repair if necessary. We are proposing this 
AD to prevent loss of structural integrity of the horizontal stabilizer 
attachment and loss of control of the airplane.

DATES: We must receive comments on this proposed AD by May 4, 2012.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, P. 
O. Box 3707, MC 2H-65, Seattle, 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: 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: nancy.marsh@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-2012-0268; 
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 received reports of incorrectly installed bolts common to the 
rear spar terminal fitting of the horizontal stabilizer. During 
manufacturing, the termination fitting bolts were installed without 
proper thread protrusion due to missing washers. This resulted in an 
unclamped condition between the horizontal stabilizer rear spar and the 
termination fitting. Loose bolts attaching the horizontal stabilizer 
termination fitting can lead to premature cracking of the fitting. This 
condition, if not corrected, could result in the loss of structural 
integrity of the horizontal stabilizer attachment and loss of control 
of the airplane.

Relevant Service Information

    We reviewed Boeing Service Bulletin 737-55-1090, dated March 30, 
2011. This service information describes procedures for 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 fasteners of the horizontal stabilizer rear spar, if necessary; 
an inspection to determine if certain bolts are installed, if 
necessary, and related investigative and corrective actions if 
necessary. This service information also describes procedures for 
repetitive high frequency eddy current (HFEC) and ultrasonic (UT) 
inspections for cracking of the termination fitting at certain bolt 
locations, and repair if necessary.
    The related investigative action is a detailed inspection for 
damage (including chafing, galling, nicks, gouges, and exposed bare 
metal) of the bolt shank. The corrective action includes installing new 
hardware, replacing the bolt with a new bolt, and contacting The Boeing 
Company for repair instructions and doing the repair.
    The initial compliance time for certain airplanes is before 32,000 
total flight cycles or within 12 months after the original issue date 
of the service information. For certain other airplanes, the initial 
compliance time is before 36,000 total flight cycles or within 12 
months after the original issue date of the service information.

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 
under ``Differences Between the Proposed AD and the Service 
Information.''

Differences Between the Proposed AD and the Service Information

    Boeing Service Bulletin 737-55-1090, dated March 30, 2011, does not 
specify doing an inspection for bolt type. This proposed AD would 
require inspection for correct bolt type. If incorrect bolt type is 
found, paragraph (k) of this proposed AD would require repair using a 
method approved in accordance with paragraph (l).
    Figure 1 of Boeing Service Bulletin 737-55-1090, dated March 30, 
2011, contains an error. The illustration of an identification plate 
that points to the location of a part number should point to the serial 
number and the example ``SAIC 1234'' should be located on the serial 
number line. This proposed AD requires an inspection for an 
identification plate with a serial number that starts with the letters 
``SAIC.''
    Boeing Service Bulletin 737-55-1090, dated March 30, 2011, 
specifies to contact the manufacturer for instructions on how to repair 
certain conditions, but this proposed AD would require repairing those 
conditions in one of the following ways:
     In accordance with a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by the Boeing Commercial 
Airplanes Organization Designation Authorization (ODA) whom

[[Page 16190]]

we have authorized to make those findings.

Costs of Compliance

    We estimate that this proposed AD affects 373 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                 $0             $85         $31,705
                                         hour = $85 per
                                         inspection cycle.
Replacement of bolts..................  17 work-hours x $85 per            1,530           2,975       1,109,675
                                         hour = $1,445.
----------------------------------------------------------------------------------------------------------------

    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 AD.
    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

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

(a) Comments Due Date

    We must receive comments by May 4, 2012.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-600, -700, -
700C, -800, and -900 series airplanes, certificated in any category, 
as identified in Boeing Service Bulletin 737-55-1090, dated March 
30, 2011.

(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 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.
    (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 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.,

[[Page 16191]]

``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) Exception to Service Bulletin

    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.''

(k) Exceptions to Corrective Actions

    If, during any inspection required by paragraphs (g) and (h) of 
this AD, any bolts other than P/N BACB30US14K() or BACB30US16K(), as 
applicable, are found: Before further flight, repair using a method 
approved in accordance with the procedures specified in paragraph 
(l) 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: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD if it is approved by the 
Boeing Commercial Airplanes Organization Designation Authorization 
(ODA) that has been authorized by the Manager, Seattle ACO to make 
those findings. For a repair method to be approved, the repair must 
meet the certification basis of the airplane, and the approval must 
specifically refer to this AD.

(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: 
nancy.marsh@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 March 8, 2012.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-6628 Filed 3-19-12; 8:45 am]
BILLING CODE 4910-13-P


