
[Federal Register Volume 77, Number 166 (Monday, August 27, 2012)]
[Proposed Rules]
[Pages 51720-51722]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-20967]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2012-0860; Directorate Identifier 2012-NM-123-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, and -900ER series 
airplanes. This proposed AD was prompted by incorrect wire support 
clamps installed within the left environmental cooling systems (ECS) 
bay, which could allow wiring to come in contact with the exposed metal 
of the improper clamp. This proposed AD would require inspections to 
identify the part number of the wire support clamp, related 
investigative actions, and corrective actions if necessary. We are 
proposing this AD to prevent electrical arcing and a potential ignition 
source, which in combination with flammable fuel vapors could result in 
a fuel tank explosion, and consequent loss of the airplane.

DATES: We must receive comments on this proposed AD by October 11, 
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; Internet https://www.myboeingfleet.com. You may review copies of the referenced service 
information at the FAA, Transport Airplane Directorate, 1601

[[Page 51721]]

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: Georgios Roussos, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; 
phone: 425-917-6482; fax: 425-917-6590; email: 
georgios.roussos@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-2012-0860; 
Directorate Identifier 2012-NM-123-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 reviewed reports of incorrect wire support clamps installed 
within the left ECS bay, which is a flammable leakage zone. Use of 
incorrect wire support clamps that are not fully cushioned could allow 
electrical power wiring to come in contact with the exposed metal of 
the improper clamp. Power wiring shorts to the exposed metal of the 
wire support clamp could produce electrical arcing. We are proposing 
this AD to prevent electrical arcing and a potential ignition source, 
which in combination with flammable fuel vapors, could result in a fuel 
tank explosion, and consequent loss of the airplane.

Relevant Service Information

    We reviewed Boeing Special Attention Service Bulletin 737-28-1303, 
dated April 26, 2012. The service information describes procedures for 
a detailed inspection of certain wire support clamps to identify part 
number TA0930034-10 wire support clamp and related investigative 
actions to verify that the flange cushions completely surround the two 
metal strap sections of the wire support clamp and to detect any 
possible chafing of the wire bundle within the left side ECS bay, and 
corrective actions if necessary. Corrective actions include replacing 
the discrepant clamp with a new or serviceable TA0930034-10 wire 
support clamp if the part number is incorrect or if the flange cushions 
do not completely surround the two metal strap sections of the wire 
support clamp, and repairing or replacing chafed wiring.

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.

Costs of Compliance

    We estimate that this proposed AD affects 297 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                     Cost per        Number of     Cost on U.S.
            Action                 Labor cost       Parts cost        product        airplanes       operators
----------------------------------------------------------------------------------------------------------------
Inspection Group 1 airplanes..  10 work-hours x               $0            $850             185        $157,250
                                 $85 per hour =
                                 $850.
Inspection Group 2 airplanes..  2 work-hours x                 0             170             112          19,040
                                 $85 per hour =
                                 $170.
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary replacements 
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 replacements.

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                 Action                                Labor cost                  Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replacement of wire support clamp.......  1 work-hour x $85 per hour = $85....              $3              $88
----------------------------------------------------------------------------------------------------------------

    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.
    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition repair of chafed or damaged wiring 
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:

[[Page 51722]]

``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-2012-0860; Directorate Identifier 
2012-NM-123-AD.

(a) Comments Due Date

    We must receive comments by October 11, 2012.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-600, -700, -800, 
and -900ER series airplanes; certificated in any category; as 
identified in Boeing Special Attention Service Bulletin 737-28-1303, 
dated April 26, 2012.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 28, Fuel System.

(e) Unsafe Condition

    This AD was prompted by incorrect wire support clamps installed 
within the left environmental cooling systems (ECS) bay, which could 
allow wiring to come in contact with the exposed metal of the 
improper clamp. We are issuing this AD to prevent electrical arcing 
and a potential ignition source, which in combination with flammable 
fuel vapors could result in a fuel tank explosion, and consequent 
loss of the airplane.

(f) Compliance

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

(g) Inspection and Corrective Actions

    Within 60 months after the effective date of this AD, do a 
detailed inspection for part number TA0930034-10 wire support clamp, 
and do all applicable related investigative and corrective actions, 
in accordance with the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-28-1303, dated April 26, 2012. Do all 
applicable related investigative and corrective actions before 
further flight.

(h) Parts Installation Prohibition

    As of the effective date of this AD, no person may install a 
wire support clamp that is not part number (P/N) TA0930034-10 within 
the left ECS bay of any airplane.

(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: 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.

(j) Related Information

    (1) For more information about this AD, contact Georgios 
Roussos, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, 
FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., 
Renton, WA 98057-3356; phone: 425-917-6482; fax: 425-917-6590; 
email: georgios.roussos@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; 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 August 17, 2012.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-20967 Filed 8-24-12; 8:45 am]
BILLING CODE 4910-13-P


