
[Federal Register Volume 76, Number 14 (Friday, January 21, 2011)]
[Proposed Rules]
[Pages 3856-3859]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-1226]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0028; Directorate Identifier 2009-NM-228-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model 737-100, -200, 
-200C, -300, -400, and -500 Series 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 Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes. This proposed AD would result in all airplanes having new 
relays with a ground fault interrupter (GFI) feature. This proposed AD 
would require, depending on airplane configuration, doing certain 
wiring changes, replacing the fuel pump power control relays for the 
main, center and auxiliary tanks, as applicable, with new relays having 
a GFI feature, performing certain bonding resistance measurements, and 
modifying relay module assemblies. The proposed AD also would require 
revising the maintenance program to incorporate Airworthiness 
Limitations (AWLs) 28-AWL-23 (for Model 737-100, 737-200, and 737-200C 
series airplanes), and 28-AWL-22 (for Model 737-300, 737-400, and 737-
500 series airplanes). This proposed AD results from fuel system 
reviews conducted by the manufacturer. We are proposing this AD to 
prevent damage to the fuel pumps caused by electrical arcing that could 
introduce an ignition source in the fuel tank, 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 March 7, 2011.

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.

[[Page 3857]]

     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; e-mail 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 or 
425-227-1152.

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 (telephone 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 (ACO), 1601 Lind Avenue, SW., Renton, Washington 
98057-3356; telephone (425) 917-6482; fax (425) 917-6590.

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-2011-0028; 
Directorate Identifier 2009-NM-228-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

    The FAA has examined the underlying safety issues involved in fuel 
tank explosions on several large transport airplanes, including the 
adequacy of existing regulations, the service history of airplanes 
subject to those regulations, and existing maintenance practices for 
fuel tank systems. As a result of those findings, we issued a 
regulation titled ``Transport Airplane Fuel Tank System Design Review, 
Flammability Reduction and Maintenance and Inspection Requirements'' 
(66 FR 23086, May 7, 2001). In addition to new airworthiness standards 
for transport airplanes and new maintenance requirements, this rule 
included Special Federal Aviation Regulation No. 88 (``SFAR 88,'' 
Amendment 21-78, and subsequent Amendments 21-82 and 21-83).
    Among other actions, SFAR 88 requires certain type design (i.e., 
type certificate (TC) and supplemental type certificate (STC)) holders 
to substantiate that their fuel tank systems can prevent ignition 
sources in the fuel tanks. This requirement applies to type design 
holders for large turbine-powered transport airplanes and for 
subsequent modifications to those airplanes. It requires them to 
perform design reviews and to develop design changes and maintenance 
procedures if their designs do not meet the new fuel tank safety 
standards. As explained in the preamble to the rule, we intended to 
adopt airworthiness directives to mandate any changes found necessary 
to address unsafe conditions identified as a result of these reviews.
    In evaluating these design reviews, we have established four 
criteria intended to define the unsafe conditions associated with fuel 
tank systems that require corrective actions. The percentage of 
operating time during which fuel tanks are exposed to flammable 
conditions is one of these criteria. The other three criteria address 
the failure types under evaluation: Single failures, single failures in 
combination with a latent condition(s), and in-service failure 
experience. For all four criteria, the evaluations included 
consideration of previous actions taken that may mitigate the need for 
further action.
    We have determined that the actions identified in this AD are 
necessary to reduce the potential of ignition sources inside fuel 
tanks, which, in combination with flammable fuel vapors, could result 
in a fuel tank explosion and consequent loss of the airplane.
    As part of an SFAR88 analysis, Boeing determined that the power 
control relays for the main tank fuel boost pumps, the center tank fuel 
boost pumps, and for certain airplanes, the auxiliary tank fuel boost 
pumps should be replaced with new relays having a ground fault 
interrupter (GFI) feature. The relays are located in the P6 circuit 
breaker panel in the flight compartment. The GFI relay feature is 
intended to protect the fuel boost pumps from damage caused from 
electrical arcing by removing electrical power from the pump if a 
ground fault is detected. Electrical arcing, if not prevented could 
introduce an ignition source in the fuel tank which, in combination 
with flammable fuel vapors, could result in a fuel tank explosion and 
consequent loss of the airplane.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 737-28A1212, 
Revision 1, dated August 27, 2010. Depending on airplane configuration 
and on whether the actions in Boeing Alert Service Bulletin 737-
28A1212, dated July 23, 2009, were accomplished, Boeing Alert Service 
Bulletin 737-28A1212, Revision 1, dated August 27, 2010, describes 
procedures for the following actions, depending on airplane 
configurations:
     Doing wiring changes,
     Replacing the fuel pump power control relays for the main, 
center and auxiliary tanks with new relays having a GFI feature,
     Doing certain bonding resistance measurements to verify 
certain bonding requirements are met, and
     Modifying the M181, M182, M183 relay module assemblies.
    Boeing Alert Service Bulletin 737-28A1212, Revision 1, dated August 
27, 2010, specifies a compliance time of 60 months for replacing the 
power control relays.
    For certain airplanes, Boeing Alert Service Bulletin 737-28A1212, 
Revision 1, dated August 27, 2010, refers to BAE Systems Service 
Bulletin 65-49808-24-01, Revision 1, dated July 19, 2010, as an 
additional source of guidance for doing the modification of the relay 
module assemblies and bond resistance measurements.
    In addition, we have reviewed Section 9 of Boeing 737-100/200/200C/
300/400/500 Airworthiness Limitations (AWLs) and Certification 
Maintenance

[[Page 3858]]

Requirements, D6-38278-CMR, Revision May 2009 (hereafter referred to as 
``Document D6-38278-CMR''). Document D6-38278-CMR describes, among 
other actions, new AWLs for the applicable fuel boost pumps that 
incorporate ground fault interrupter relays for certain Model 737-100, 
-200, and -200C airplanes (i.e., AWL 28-AWL-23), and for certain other 
Model 737-300, -400, and -500 airplanes (i.e., AWL 28-AWL-22). The AWL 
reference to boost pumps applies also to all pumps where the GFI has 
been installed by incorporating Boeing Alert Service Bulletin 737-
28A1212.

FAA's Determination and Requirements of This Proposed AD

    We are proposing this AD because we evaluated all relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design. 
This proposed AD would require accomplishing the actions specified in 
the service information described previously, except as described under 
``Difference Between the Proposed AD and Service Information.''

Difference Between the Proposed AD and Service Information

    AWL 28-AWL-23 of Section 9 of Boeing 737-100/200/200C/300/400/500 
Airworthiness Limitations (AWLs) and Certification Maintenance 
Requirements (CMRs), Document D6-38278-CMR, Revision May 2009, is 
applicable to Model 737-100, -200, and -200C airplanes, although it 
specifies only the Model 737-100 and -200 airplanes.

Costs of Compliance

    We estimate that this proposed AD would affect 750 airplanes of 
U.S. registry. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

                                                                 Table--Estimated Costs
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                                                                                                                   Number of U.S.-
               Action                     Work hours        Average labor       Parts         Cost per product       registered          Fleet cost
                                                            rate per hour                                             airplanes
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Replacement of power control relays  4 to 9 \1\..........             $85         $14,500  $14,840 to $15,265 \1\             750  $11,130,000 to
                                                                                                                                    $11,448,750.\1\
Modification.......................  5...................              85               0  $425..................             750  $318,750.
Maintenance program revision.......  1...................              85               0  $85...................             750  $63,750.
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\1\ Depending on airplane configuration.

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), and
    3. 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

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 AD:

The Boeing Company: Docket No. FAA-2011-0028; Directorate Identifier 
2009-NM-228-AD.

Comments Due Date

    (a) We must receive comments by March 7, 2011.

Affected ADs

    (b) None.

Applicability

    (c) 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-
28A1212, Revision 1, dated August 27, 2010.

    Note 1: This AD requires revisions to certain operator 
maintenance documents to include new inspections. Compliance with 
these inspections is required by 14 CFR 91.403(c). For airplanes 
that have been previously modified, altered, or repaired in the 
areas addressed by these inspections, the operator may not be able 
to accomplish the inspections described in the revisions. In this 
situation, to comply with 14 CFR 91.403(c), the operator must 
request approval for an alternative method of compliance according 
to paragraph (m) of this AD. The request should include a 
description of changes to the required inspections that will ensure 
the continued operational safety of the airplane.

Subject

    (d) Air Transport Association (ATA) of America Code 28: Fuel.

[[Page 3859]]

Unsafe Condition

    (e) This AD results from fuel system reviews conducted by the 
manufacturer. The Federal Aviation Administration is issuing this AD 
to prevent the damage to the fuel pumps caused by electrical arcing 
that could introduce an ignition source in the fuel tank, which, in 
combination with flammable fuel vapors, could result in a fuel tank 
explosion and consequent loss of the airplane.

Compliance

    (f) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Part 1: Wiring Changes, Relay Replacements, and Certain Bonding 
Resistance Measurements for Certain Airplanes

    (g) For airplanes on which Boeing Alert Service Bulletin 737-
28A1212, dated July 23, 2009, has not been incorporated as of the 
effective date of this AD: Within 60 months after the effective date 
of this AD, do the applicable action required by paragraph (g)(1) or 
(g)(2) of this AD.
    (1) Airplanes without the M181, M182, and M183 supplier relay 
modules installed: Do the wiring changes; replace the fuel pump 
power control relays for the main, center, and auxiliary tanks, as 
applicable, with new relays having a ground fault interrupter (GFI) 
feature; and do certain bonding resistance measurements to verify 
that certain bonding requirements are met; in accordance with Part 1 
of the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-28A1212, Revision 1, dated August 27, 2010.
    (2) Airplanes with the M181, M182, and M183 supplier relay 
modules installed: Modify the M181, M182, and M183 relay module 
assemblies, and do certain bonding resistance measurements to verify 
that certain bonding requirements are met, in accordance with Part 1 
of the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-28A1212, Revision 1, dated August 27, 2010.

    Note 2:  Boeing Alert Service Bulletin 737-28A1212, Revision 1, 
dated August 27, 2010, refers to BAE Systems Service Bulletin 65-
49808-24-01, Revision 1, dated July 19, 2010, as an additional 
source of guidance for doing the modification and certain bonding 
resistance measurements.

Part 2: Wiring Changes and Certain Bonding Measurements for Certain 
Airplanes

    (h) For airplanes on which Boeing Alert Service Bulletin 737-
28A1212, dated July 23, 2009, has been incorporated as of the 
effective date of this AD, and on which the M181, M182, and M183 
supplier relay modules have not been installed: Within 60 months 
after the effective date of this AD, do the wiring changes and 
certain bonding measurements to verify that certain bonding 
requirements are met, in accordance with Part 2 of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
28A1212, Revision 1, dated August 27, 2010.

Part 3: Certain Bonding Measurements for Certain Airplanes

    (i) For airplanes on which Boeing Alert Service Bulletin 737-
28A1212, dated July 23, 2009, has been incorporated as of the 
effective date of this AD, and that the M181, M182, and M183 
supplier relay modules are installed: Within 60 months after the 
effective date of this AD, do certain bonding measurements to verify 
that certain bonding requirements are met, in accordance with Part 3 
of the Accomplishment Instructions of Boeing Alert Service Bulletin 
737-28A1212, Revision 1, dated August 27, 2010.

    Note 3:  Boeing Alert Service Bulletin 737-28A1212, Revision 1, 
dated August 27, 2010, refers to BAE Systems Service Bulletin 65-
49808-24-01, Revision 1, dated July 19, 2010, as an additional 
source of guidance for doing the modification and certain bonding 
resistance measurements.

Maintenance Program Revisions

    (j) Concurrently with accomplishing the actions required by 
paragraph (g), (h), or (i) of this AD, as applicable, or within 30 
days after the effective date of this AD, whichever occurs later, 
revise the maintenance program by incorporating the applicable 
airworthiness limitation (AWL) specified in paragraph (j)(1) or 
(j)(2) of this AD.
    (1) For Model 737-100, -200, and -200C series airplanes: 
Airworthiness Limitation 28-AWL-23 of Section 9 of Boeing 737-100/
200/200C/300/400/500 AWL and Certification Maintenance Requirements 
(CMRs), Document D6-38278-CMR, Revision May 2009. The initial 
compliance time for the actions specified in AWL 28-AWL-23 is within 
1 year after accomplishing the installation required by paragraph 
(g), (h), or (i) of this AD, or within 1 year after the effective 
date of this AD, whichever occurs later.
    (2) For Model 737-300, -400, and -500 series airplanes: AWL 28-
AWL-22 of Section 9 of Boeing 737-100/200/200C/300/400/500 
Airworthiness Limitation (AWL) and Certification Maintenance 
Requirements (CMRs), Document D6-38278-CMR, Revision May 2009. The 
initial compliance time for the actions specified in AWL 28-AWL-22 
is within 1 year after accomplishing the installation required by 
paragraph (g), (h), or (i) of this AD, or within 1 year after the 
effective date of this AD, whichever occurs later.

No Alternative Inspections or Inspection Interval

    (k) After accomplishment of the action required by paragraph 
(g), (h), or (i) of this AD, as applicable, no alternative 
inspections or inspection intervals may be used, unless the 
inspections or intervals are approved as an alternative means of 
compliance in accordance with the procedures specified in paragraph 
(m) of this AD.

Credit for Actions Accomplished in Accordance With Earlier Revisions of 
AWLs

    (l) Revising the maintenance program to incorporate AWLs 28-AWL-
22 (for Model 737-300, -400, and -500 airplanes) and 28-AWL-23 (for 
Model 737-100, -200, and -200C airplanes) in accordance with 
paragraphs (g)(1) and (g)(2) of AD 2008-10-09 R1, amendment 39-
16148, terminates the requirements of paragraph (j) of this AD.

Alternative Methods of Compliance (AMOCs)

    (m)(1) The Manager, Seattle Aircraft Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested using 
the procedures found in 14 CFR 39.19. Send information to ATTN: 
Georgios Roussos, Aerospace Engineer, Systems and Equipment Branch, 
ANM-130S, FAA, Seattle Aircraft Certification Office (ACO), 1601 
Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6482; fax (425) 917-6590. Or, e-mail information 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.

    Issued in Renton, Washington, on January 12, 2011.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-1226 Filed 1-20-11; 8:45 am]
BILLING CODE 4910-13-P


