[Federal Register Volume 67, Number 161 (Tuesday, August 20, 2002)]
[Proposed Rules]
[Pages 53893-53895]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-21053]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
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 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.
 
 ========================================================================
 

  Federal Register / Vol. 67, No. 161 / Tuesday, August 20, 2002 / 
Proposed Rules  

[[Page 53893]]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NM-44-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 737-600, -
700, -700C, -800, and -900 series airplanes. This proposal would 
require replacement of the existing fueling float switch and conduit 
assemblies in the main and center fuel tanks with new, improved 
assemblies. This action is necessary to prevent fluid contamination 
inside the fueling float switch or chafing of the wiring to the in-tank 
conduit, which could generate an ignition source and consequent fire 
and explosion in the fuel tank. This action is intended to address the 
identified unsafe condition.

DATES: Comments must be received by October 4, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2002-NM-44-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2002-NM-44-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Doug Pegors, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-1446; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2002-NM-44-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2002-NM-44-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On February 23, 1999, the FAA issued AD 99-05-12, amendment 39-
11060 (64 FR 10213, March 3, 1999), applicable to certain Boeing Model 
737-100, -200, -300, -400, and -500 series airplanes. That AD requires 
removal of the float switch and wiring and inspection of the float 
switch wiring in the center fuel tank to detect discrepancies, and 
either reinstallation of existing float switch and wiring, or 
replacement of the float switch and wiring with a new float switch and 
wiring. That action also requires installation of Teflon sleeving over 
the wiring of the float switch. In lieu of the above mentioned 
requirements, that AD requires deactivation of the float switch, 
accomplishment of specific fueling procedures, and installation of 
Caution signs. Any damaged components that were found during the 
inspections required by that AD were removed and returned to the 
airplane manufacturer for investigation. Examination of the returned 
components revealed that the potential for water and fuel contamination 
of the internal components of the float switch could provide a path for 
electrical current from the switch to ground. Such a path could 
generate an ignition source and consequent fire and explosion in the 
fuel tank.

Actions Since Issuance of AD 99-05-12

    Since the issuance of AD 99-05-12, the manufacturer has designed a 
new, improved fueling float switch and conduit assemblies. The new 
float switch is more resistant to fuel and moisture contamination. The 
new electrical cable conduit for the float switch eliminates sharp 
bends within

[[Page 53894]]

the conduit and includes a liner system installed inside the conduit to 
provide added protection against chafing of the float switch wiring. 
These improvements are designed to eliminate a potential ignition 
source in the fuel tanks.
    AD 99-05-12 did not include Model 737-600, -700, -700C, -800, and -
900 series airplanes in the applicability in anticipation of the 
availability of redesigned components for those airplanes; therefore, 
those models are addressed in this proposed AD. The FAA is currently 
considering replacement of the fueling float switch and conduit 
assemblies for Model 737-100, -200, -300, -400, and -500 series 
airplanes, once the redesigned components are available for those 
models.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
737-28A1142, dated February 7, 2002, which describes procedures for 
replacement of the existing fueling float switch and conduit assemblies 
in the main and center fuel tanks with new, improved assemblies. Each 
assembly includes a new, improved float switch, and a new conduit 
assembly with a liner system inside the conduit. Accomplishment of the 
actions specified in the service bulletin is intended to adequately 
address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require accomplishment of the actions specified in 
the service bulletin described previously.

Cost Impact

    There are approximately 478 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 392 airplanes of U.S. registry 
would be affected by this proposed AD.
    It would take approximately 56 work hours per airplane to 
accomplish the proposed replacement in the 2 main fuel tanks, as 
specified in Work Package I, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of the work hours for 
this proposed replacement on U.S. operators is estimated to be 
$1,317,120, or $3,360 per airplane.
    It would take approximately 23 work hours per airplane to 
accomplish the proposed replacement in the center fuel tank, as 
specified in Work Package II, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of the work hours for 
this proposed replacement on U.S. operators is estimated to be 
$540,960, or $1,380 per airplane.
    The kit required to accomplish the proposed replacement in all 
three fuel tanks would cost approximately $5,116 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed requirements 
of this AD action, and that no operator would accomplish those actions 
in the future if this proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

Regulatory Impact

    The regulations proposed herein 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. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that 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) if promulgated, 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. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new 
airworthiness directive:

    Boeing: Docket 2002-NM-44-AD.

    Applicability: Model 737-600, -700, -700C, -800, and -900 series 
airplanes, certificated in any category, as listed in Boeing Alert 
Service Bulletin 737-28A1142, dated February 7, 2002.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (b) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent fluid contamination inside the fueling float switch 
or chafing of the wiring to the in-tank conduit, which could 
generate an ignition source and consequent fire and explosion in the 
fuel tank, accomplish the following:

Replacement

    (a) Replace the existing fueling float switch and conduit 
assemblies in the main and center fuel tanks with new, improved 
assemblies (includes a new float switch and a new conduit assembly 
with a liner system inside the conduit), at the applicable time 
specified in paragraph (a)(1), (a)(2), or (a)(3) of this AD, per 
Work Packages I and II of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-28A1142, dated February 7, 2002.

    Note 2: Due to the lack of sleeving on the existing electrical 
wire installations of the center fuel tank, it is recommended that 
Work Package II be completed before Work Package I.

    (1) For airplanes that have accumulated fewer than 5,000 total 
flight cycles as of the effective date of this AD: Within 2 years 
after the effective date of this AD.
    (2) For airplanes that have accumulated 5,000 total flight 
cycles or more, but fewer than 10,000 total flight cycles as of the 
effective date of this AD: Within 1 year after the effective date of 
this AD.
    (3) For airplanes that have accumulated 10,000 total flight 
cycles or more as of the effective date of this AD: Within 180 days 
after the effective date of this AD.

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Alternative Methods of Compliance

    (b) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Seattle ACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permit

    (c) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

    Issued in Renton, Washington, on August 13, 2002.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-21053 Filed 8-19-02; 8:45 am]
BILLING CODE 4910-13-P