[Federal Register Volume 65, Number 192 (Tuesday, October 3, 2000)]
[Proposed Rules]
[Pages 58966-58968]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-25327]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-313-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-300, -400, and -500 
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 all Boeing Model 737-300, -400, 
and -500 series airplanes. This proposal would require, among other 
actions, a one-time detailed visual inspection of the fuel quantity 
indicating system (FQIS) wiring and fuel tubing on the inboard side of 
the right wing rib wing buttock line (WBL) 227 and on the aft side of 
stringer No. 13 to determine if clearance exists between the FQIS wire 
harness and the refuel tube and tube coupling, and to detect any loose 
or broken refuel tube clamp or bracket or chafing of the FQIS wire 
harness; and corrective actions, if necessary. This action is necessary 
to detect and correct chafing and to prevent electrical contact between 
the FQIS wiring and the surrounding structure, which, in conjunction 
with another wiring failure outside the fuel tank, could result in fire 
or explosion of the fuel tank. This action is intended to address the 
identified unsafe condition.

DATES: Comments must be received by November 2, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-313-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. 2000-NM-313-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: Sherry Vevea, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 227-1360; 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 notice 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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-313-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. 2000-NM-313-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received two reports of chafing of the wire harness of 
the fuel quantity indicating system (FQIS) in the right main fuel tank 
inboard of right wing station wing buttock line (WBL) 227. Both of 
these reports indicated that wires were chafed down to the conductor. 
Investigation of one of those events revealed that the refuel tube 
clamp broke due to a preload on the clamp. The refuel tube shifted 
position, and the refuel tube coupling chafed against the FQIS wire 
harness. The tube coupling has a knurled surface and a lockwire that, 
if not located correctly, can chafe the FQIS wiring. A chafed or bare 
FQIS wire normally operates at five volts and does not constitute an 
in-tank ignition source without an additional failure condition such as 
wire bundle shorts outside the fuel tank.
    Chafing and arcing between the FQIS wiring and the surrounding 
structure, in conjunction with another wiring failure outside the fuel 
tank, could result in fire or explosion of the fuel tank.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
737-28A1168, dated September 26, 2000. The service bulletin describes 
procedures for a one-time detailed visual inspection of the FQIS wiring 
and fuel tubing on the inboard side of the right wing rib WBL 227 and 
on the aft side of stringer No. 13 to determine if a \3/8\-inch 
clearance exists between the FQIS wire harness and the refuel tube and 
tube coupling, and to detect any loose or broken refuel tube clamp or 
bracket or chafing of the FQIS wire harness; and corrective actions, if 
necessary. The corrective actions, if necessary, involve the following:
     Readjusting the refuel tube;
     Relocating the bonding jumper away from the FQIS wiring;
     Replacing the broken clamp with a new clamp;
     Repairing the broken bracket or replacing the broken 
bracket with a new bracket;
     Securing the loose clamp or bracket;
     Replacing the wire harness with a new wire harness;
     Repairing the wire harness;
     Splicing the wires; and
     Installing a teflon sleeve.

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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, except as discussed below. 
The proposed AD also would require that operators submit a plan to the 
FAA that identifies a schedule for compliance with the requirements of 
the proposed AD and report results of inspection findings to the 
manufacturer.

Difference Between This Proposed AD and the Service Bulletin

    The FAA recognizes that this proposed AD would require entry into 
the fuel tank, which would require taking the airplane out of service 
for as much as two days. This lengthy shop visit, as well as the 
relatively short compliance time (six months) required to accomplish 
this proposed AD, make it necessary for operators to engage in 
compliance planning to ensure that, when the deadline for compliance 
arrives, all of the required actions have been completed on all 
affected airplanes. Therefore, paragraph (a) of this proposed AD would 
require that operators submit to the FAA a compliance plan within 15 
days after the effective date. This will enable the FAA to verify that 
all operators will be able to meet the deadlines imposed by this 
proposed AD.

Interim Action

    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.

Cost Impact

    There are approximately 1,974 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 796 airplanes of U.S. 
registry would be affected by this proposed AD.
    It would take approximately 1 work hour per airplane to accomplish 
the proposed inspection, at an average labor rate of $60 per work hour. 
Based on the figures, the cost impact of the inspection proposed by 
this AD on U.S. operators is estimated to be $47,760, or $60 per 
airplane.
    It would take approximately 16 work hours to accomplish the 
proposed compliance plan, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of the compliance plan 
proposed by this AD on U.S. operators is estimated to be $960.
    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 2000-NM-313-AD.

    Applicability: All Model 737-300, -400, and -500 series 
airplanes, certificated in any category.

    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 (d) 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 detect and correct chafing and to prevent electrical contact 
between the fuel quantity indicating system (FQIS) wiring and the 
surrounding structure, which, in conjunction with another wiring 
failure outside the fuel tank, could result in fire or explosion of 
the fuel tank, accomplish the following:

Compliance Plan

    (a) Within 15 days after the effective date of this AD, submit a 
plan to the FAA that identifies a schedule for compliance with 
paragraph (b) of this AD. This schedule must include, for each of 
the operator's affected airplanes, the dates and maintenance events 
(e.g., letter checks) when the required actions will be 
accomplished. For purposes of this paragraph, ``FAA'' means the 
Principal Maintenance Inspector (PMI) for operators that are 
assigned a PMI, or the cognizant Flight Standards District Office 
for other operators. Information collection requirements contained 
in this regulation have been approved by the Office of Management 
and Budget (OMB) under the provisions of the Paperwork Reduction Act 
of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control 
Number 2120-0056.

Inspection and Corrective Actions

    (b) Within 6 months after the effective date of this AD, perform 
a one-time detailed visual inspection of the FQIS wiring and fuel 
tubing on the inboard side of the right wing rib wing buttock line 
(WBL) 227 and on the aft side of stringer No. 13 to determine if a 
\3/8\-inch clearance exists between the FQIS wire harness and the 
refuel tube and tube coupling, and to detect any loose or broken 
refuel tube clamp or bracket or chafing of the FQIS wire harness, in 
accordance with Boeing Alert Service Bulletin 737-28A1168, dated 
September 26, 2000.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror,

[[Page 58968]]

magnifying lenses, etc., may be used. Surface cleaning and elaborate 
access procedures may be required.''


    (1) If the clearance between the FQIS wire harness and the 
refuel tube is less than \3/8\-inch, prior to further flight, 
readjust the refuel tube, and relocate the bonding jumper away from 
the wiring, if necessary, in accordance with the service bulletin.
    (2) If any loose or broken refuel tube clamp or bracket is 
found, prior to further flight, replace the broken clamp with a new 
clamp; repair the broken bracket or replace the broken bracket with 
a new bracket; and secure the loose clamp or bracket; as applicable; 
in accordance with the service bulletin.
    (3) If any chafing of the FQIS wiring harness is found, prior to 
further flight, replace the wire harness with a new wire harness or 
accomplish the applicable action(s) specified in paragraph 
(b)(3)(i), (b)(3)(ii), or (b)(3)(iii) of this AD, in accordance with 
the service bulletin.
    (i) For jacket damage only that is less than 1-inch in length 
with no sign of abrasion to the wire insulation: Install a teflon 
sleeve over the wiring. At the next scheduled ``C'' Check, but no 
later than 15 months after the effective of this AD, repair the wire 
harness or replace the wire harness with a new wire harness.
    (ii) For jacket damage or a harness with an exposed shield or 
conductor and the insulation of the other wire is not damaged (there 
can be no broken shield strands if the shield wire is damaged or no 
broken wire strands if the unshielded wire is damaged): Install a 
teflon sleeve over the wiring terminal and along the wire to the 
damaged area.
    (iii) For wire harness damage to the wire shield of the shielded 
wire or to the conductor of the unshielded wire: Splice the wires 
and install a teflon sleeve over the splice.

Reporting Requirement

    (c) Submit a report of inspection findings to Service Bulletin 
Engineering, Boeing Commercial Airplane Group, P.O. Box 3707, Mail 
Stop 2H-37, Seattle, Washington 98124-2207; at the applicable time 
specified in paragraph (c)(1) or (c)(2) of this AD. The report must 
include all the information specified in paragraph K. of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
28A1168, dated September 26, 2000. Information collection 
requirements contained in this regulation have been approved by the 
Office of Management and Budget (OMB) under the provisions of the 
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have 
been assigned OMB Control Number 2120-0056.
    (1) For airplanes on which the inspection required by paragraph 
(b) of this AD is accomplished after the effective date of this AD: 
Submit the report within 10 days after performing the inspection.
    (2) For airplanes on which the inspection required by paragraph 
(b) of this AD has been accomplished prior to the effective date of 
this AD: Submit the report within 10 days after the effective date 
of this AD.

Alternative Methods of Compliance

    (d) 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. Operators shall submit their requests through an 
appropriate FAA PMI, 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 Permits

    (e) 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 September 26, 2000.
John J. Hickey,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-25327 Filed 10-2-00; 8:45 am]
BILLING CODE 4910-13-P