[Federal Register Volume 77, Number 162 (Tuesday, August 21, 2012)]
[Proposed Rules]
[Pages 50414-50417]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-20476]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2012-0857; Directorate Identifier 2011-NM-244-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 737-100, -200, -200C, -300, -400, and 
-500 series airplanes. This proposed AD was prompted by a report of an 
approximate 8-inch crack found in the fuselage skin under the aft drain 
mast. This proposed AD would require a detailed inspection for cracking 
and corrosion of the channel and fillers adjacent to the drain mast 
bolts, an inspection to determine the location of the bonding strap, a 
measurement of the washers under the drain mast bolts, and related 
investigative actions and repair if necessary. We are proposing this AD 
to detect and correct cracking in the fuselage skin and internal 
support structure, which could result in uncontrolled decompression of 
the airplane.

DATES: We must receive comments on this proposed AD by October 5, 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.

[[Page 50415]]

     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, WA 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, WA. 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: Wayne Lockett, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6447; 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 proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2012-0857; 
Directorate Identifier 2011-NM-244-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 a report of an aft drain mast found loose on a Model 
737-400 series airplane with approximately 30,500 total flight cycles. 
Further investigation revealed the fuselage skin and surrounding back-
up structure were cracked. An 8-inch crack common to the fuselage skin 
was hidden under the drain mast. The crack was likely caused by 
incorrect installation of the drain mast. A drain mast that is not 
installed correctly can cause cracks in the fuselage skin and the 
internal support structure. The skin cracks cannot be seen because they 
are hidden by the drain mast. This condition, if not corrected, could 
result in uncontrolled decompression of the airplane.

Relevant Service Information

    We reviewed Boeing Alert Service Bulletin 737-53A1318, dated 
October 31, 2011.
    For airplanes identified as Group 1 in Boeing Alert Service 
Bulletin 737-53A1318, dated October 31, 2011, this service bulletin 
describes procedures for doing a detailed inspection for cracking and 
corrosion of the channel and fillers adjacent to the drain mast bolts, 
an inspection to determine the location of the bonding strap, a 
measurement of the washers under the drain mast bolts, and related 
investigative actions and repair if necessary. Related investigative 
actions include removing the drain mast and doing a high frequency eddy 
current (HFEC) and detailed inspection for cracking and corrosion of 
the skin, channel, and fillers. This service bulletin also specifies 
contacting Boeing for repair instructions and doing the repair.
    For airplanes identified as Group 2 in Boeing Alert Service 
Bulletin 737-53A1318, dated October 31, 2011, this service bulletin 
specifies contacting Boeing for inspection and repair instructions and 
doing the actions.
    The compliance time for the inspection is within 120 days, and 
before further flight for the repair.

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 Alert Service Bulletin 737-53A1318, dated October 31, 2011, 
specifies to contact the manufacturer for instructions on how to 
inspect and repair certain conditions, but this proposed AD would 
require that those actions be accomplished 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 we have 
authorized to make those findings.

Costs of Compliance

    We estimate that this proposed AD affects 612 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
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                                                                                    Cost per       Cost on U.S.
               Action                       Labor cost            Parts cost        product         operators
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Detailed inspection, bonding strap   4 work-hours x $85 per                $0             $340         $208,080
 inspection, washer measurement.      hour = $340.
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    We estimate the following costs to do certain necessary conditional 
actions that would be required based on the results of the proposed 
inspection. We have no way of determining the number of aircraft that 
might need these actions:

[[Page 50416]]



                                               On-condition Costs
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                                                                                                      Cost per
                   Action                                   Labor cost                 Parts cost      product
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Drain mast removal, HFEC and detailed        5 work-hours x $85 per hour = $425.....           $0          $425
 inspections, and drain mast installation.
----------------------------------------------------------------------------------------------------------------

    We have received no definitive data that would enable us to provide 
a cost estimate for the repair 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, 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-2012-0857; Directorate Identifier 
2011-NM-244-AD.

(a) Comments Due Date

    We must receive comments by October 5, 2012.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes, certificated in any 
category, as identified in Boeing Alert Service Bulletin 737-
53A1318, dated October 31, 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 a report of an approximate 8-inch crack 
found in the fuselage skin under the aft drain mast. We are issuing 
this AD to detect and correct cracking in the fuselage skin and 
internal support structure, which could result in uncontrolled 
decompression of the airplane.

(f) Compliance

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

(g) Inspection and Repair

    (1) For airplanes identified as Group 1 airplanes in Boeing 
Alert Service Bulletin 737-53A1318, dated October 31, 2011: At the 
times specified in paragraph 1.E. ``Compliance,'' of Boeing Alert 
Service Bulletin 737-53A1318, dated October 31, 2011, do the actions 
specified in paragraphs (g)(1)(i), (g)(1)(ii), and (g)(1)(iii) of 
this AD, and do all related investigative actions and repair, as 
applicable, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1318, dated October 31, 2011, 
except as required by paragraph (h) of this AD. Related 
investigative actions and repairs must be done before further 
flight. If the drain mast is found to be installed correctly, no 
further action is required by this paragraph.
    (i) Do a detailed inspection for cracking and signs of corrosion 
of the channel and the fillers adjacent to the drain mast bolts.
    (ii) Inspect the bonding strap for the correct location.
    (iii) Measure the diameter and thickness of the washers under 
the drain mast bolts.
    (2) For airplanes identified as Group 2 airplanes in Boeing 
Alert Service Bulletin 737-53A1318, dated October 31, 2011: Within 
120 days after the effective date of this AD, inspect and repair, as 
required, using a method approved in accordance with the procedures 
specified in paragraph (i) of this AD. Repairs must be done before 
further flight.

(h) Exception

    (1) Where Paragraph 1.E., ``Compliance,'' of Boeing Alert 
Service Bulletin 737-53A1318, dated October 31, 2011, specifies a 
compliance time after the original issue date of Boeing Alert 
Service Bulletin 737-53A1318, dated October 31, 2011, this AD 
requires compliance within the specified compliance time after the 
effective date of this AD.
    (2) For airplanes identified as Group 1 airplanes in Boeing 
Alert Service Bulletin 737-53A1318, dated October 31, 2011: If any 
cracking or sign of corrosion is found during any inspection 
required by this AD, and Boeing Alert Service Bulletin 737-53A1318, 
dated October 31, 2011, specifies to contact Boeing for appropriate 
action, before further flight, repair the crack or sign of corrosion 
using a method approved in accordance with the procedures specified 
in paragraph (i) of this AD.

(i) 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

[[Page 50417]]

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.

(j) Related Information

    (1) For more information about this AD, contact Wayne Lockett, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; 
phone: 425-917-6447; 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, WA 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, WA. For information on the availability of 
this material at the FAA, call 425-227-1221.

    Issued in Renton, Washington, on August 8, 2012.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-20476 Filed 8-20-12; 8:45 am]
BILLING CODE 4910-13-P