Document ID: FAA-2007-28348-0013
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes
Posted Date: 2009-03-23T04:00Z

[Federal Register: March 23, 2009 (Volume 74, Number 54)]
[Proposed Rules]               
[Page 12094-12096]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr23mr09-13]                         

========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

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[[Page 12094]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28348; Directorate Identifier 2007-NM-060-AD]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, and -900 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

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

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

SUMMARY: We are revising an earlier proposed airworthiness directive 
(AD) for certain Boeing Model 737-600, -700, -700C, -800 and -900 
series airplanes. The original NPRM would have required sealing the 
fasteners on the front and rear spars inside the main fuel tank and on 
the lower panel of the center fuel tank, inspecting the wire bundle 
support installation in the equipment cooling system bays to identify 
the type of clamp installed and determine whether the Teflon sleeve is 
installed, and doing related corrective actions if necessary. We 
subsequently issued a supplemental NPRM to revise the compliance time 
for the corrective actions specified in the original NPRM. This action 
resulted from a design review of fuel tank systems. This second 
supplemental revises the original NPRM by clarifying the applicability 
of certain actions for certain airplanes. We are proposing this second 
supplemental NPRM to prevent arcing at certain fuel tank fasteners in 
the event of a lightning strike or fault current event, 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 supplemental NPRM by April 17, 
2009.

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.
     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: Samuel Spitzer, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 
(425) 917-6510; 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-2007-
28348; Directorate Identifier 2007-NM-060-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 a supplemental notice of proposed rulemaking (NPRM) (the 
``first supplemental NPRM'') to amend 14 CFR part 39 to include an 
airworthiness directive (AD) that would apply to certain Boeing Model 
737-600, -700, -700C, -800 and -900 series airplanes. The first 
supplemental NPRM was published in the Federal Register on January 2, 
2008 (73 FR 73). That first supplemental NPRM proposed to require 
sealing the fasteners on the front and rear spars inside the main fuel 
tank and on the lower panel of the center fuel tank, inspecting the 
wire bundle support installation in the equipment cooling system bays 
to identify the type of clamp installed and determine whether the 
Teflon sleeve is installed, and doing related corrective actions if 
necessary.

Actions Since Supplemental NPRM Was Issued

    Since we issued the first supplemental NPRM, Boeing has revised 
Boeing Alert Service Bulletin 737-57A1279, dated January 24, 2007, 
(which we referred to as the appropriate source of service information 
in the first supplemental NPRM), because certain airplanes were 
assigned to an incorrect group number. Additional work is necessary for 
the mis-assigned airplanes. The additional work includes sealing the 
fuel tank fastener and general visual inspections of the wire bundle 
support installation, as applicable. We have reviewed Boeing Alert 
Service Bulletin 737-57A1279, Revision 1, dated September 25, 2008

[[Page 12095]]

(``Revision 1 of the service bulletin''). Revision 1 of the service 
bulletin includes a change to the service bulletin effectivity as well 
as changes to the access instructions for the Krueger flap operation.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We considered the comment received.

Request for More Detailed Information in Airplane Maintenance Manuals 
(AMMs)

    Continental Airlines (CAL) is concerned that not enough attention 
has been given in the proposed AD to ensure that the specific detailed 
inspections are preserved for the long-term operation of the CAL fleet. 
CAL notes that the AMM includes only generic information. CAL states 
that including information detailed by the airplane's production 
drawings must be available in manuals that are routinely used by 
maintenance personnel. Including this information will prevent 
inadvertent reversal of the design configuration that can lead to 
creating potential ignition sources.
    We infer that CAL would like us to revise the first supplemental 
NPRM to include an action to revise maintenance documents that are 
routinely used by maintenance personnel. We partially agree. We agree 
that ensuring that the requirements of the proposed AD are maintained 
throughout the life of the airplane maintains the required level of 
safety for this design. We disagree with delaying the issuance of the 
AD while the manufacturer works through its processes to develop 
revisions to the maintenance documents. We have determined that an 
unsafe condition exists and that the actions proposed in this second 
supplemental NPRM must be mandated in a timely fashion to ensure 
continued operational safety. If the revised maintenance documents are 
available and approved, we might consider further rulemaking at that 
time.
    In addition, we note that as a result of CAL's comment, we have 
initiated discussions with Boeing about including more detail in the 
Instructions for Continued Airworthiness (ICA) to ensure that the 
proposed requirements are maintained throughout the life of the 
airplane. We have not changed the supplemental NPRM regarding this 
issue.

Explanation of Additional Change

    We have added a new paragraph (d) to this second supplemental NPRM 
to identify the Air Transport Association (ATA) of America code for the 
unsafe condition. We have re-lettered subsequent paragraphs 
accordingly.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

    We are proposing this supplemental NPRM because we evaluated all 
pertinent information and determined an unsafe condition exists and is 
likely to exist or develop on other products of the same type design. 
Certain changes described above expand the scope of the original NPRM. 
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 second supplemental NPRM.

Costs of Compliance

    There are about 1,754 airplanes of the affected design in the 
worldwide fleet; of these, 645 airplanes are U.S. registered. The 
following table provides the estimated costs for U.S. operators to 
comply with this second supplemental NPRM, at an average hourly labor 
rate of $80.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                  Number of U.S.-
             Action                    Group        Work hours       Cost per       registered      Fleet cost
                                                                     airplane        airplanes
----------------------------------------------------------------------------------------------------------------
Sealant application.............               1              62          $4,960             586      $2,906,560
                                               2              28           2,240              44          98,560
                                               3              28           2,240              15          33,600
Inspection......................               1               4             320             586         187,520
                                               2               4             320              44          14,080
                                               3               2             160              15           2,400
----------------------------------------------------------------------------------------------------------------

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,

[[Page 12096]]

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:

Boeing: Docket No. FAA-2007-28348; Directorate Identifier 2007-NM-
060-AD.

Comments Due Date

    (a) We must receive comments by April 17, 2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Model 737-600, -700, -700C, -800 and -900 
series airplanes, certificated in any category; as identified in 
Boeing Alert Service Bulletin 737-57A1279, Revision 1, dated 
September 25, 2008.

Subject

    (d) Air Transport Association (ATA) of America Code 57: Wings.

Unsafe Condition

    (e) This AD results from a design review of the fuel tank 
systems. The Federal Aviation Administration is issuing this AD to 
prevent arcing at certain fuel tank fasteners in the event of a 
lightning strike or fault current event, 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.

Fastener Sealant

    (g) Within 60 months after the effective date of this AD: Seal 
the fasteners on the front and rear spars inside the main fuel tank 
and on the lower panel of the center fuel tank, as applicable, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-57A1279, Revision 1, dated September 25, 2008.

Inspection

    (h) Within 60 months after the effective date of this AD: 
Perform a general visual inspection of the wire bundle support 
installation in the equipment cooling system bays to identify the 
type of clamp installed, and determine whether the Teflon sleeve is 
installed. Do these actions in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-57A1279, Revision 
1, dated September 25, 2008 (``the service bulletin''). Do all 
applicable corrective actions before further flight in accordance 
with the service bulletin.

Actions Accomplished Previously

    (i) Actions done before the effective date of this AD in 
accordance with Boeing Alert Service Bulletin 737-57A1279, dated 
January 24, 2007, are acceptable for compliance with the 
corresponding requirements of this AD only for the following line 
numbers (L/Ns): LNs 1 through 570 inclusive, and L/Ns 1692 through 
1754 inclusive.

Alternative Methods of Compliance (AMOCs)

    (j)(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. Send information to 
Attn: Samuel Spitzer, Aerospace Engineer, Propulsion Branch, ANM-
140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, 
SW., Renton, Washington 98057-3356; telephone (425) 917-6510; fax 
(425) 917-6590.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your principal maintenance inspector (PMI) or 
principal avionics inspector (PAI), as appropriate, in the FAA 
Flight Standards District Office (FSDO), or lacking a principal 
inspector, your local FSDO. The AMOC approval letter must 
specifically reference this AD.

    Issued in Renton, Washington, on March 10, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E9-6217 Filed 3-20-09; 8:45 am]

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