[Federal Register Volume 63, Number 91 (Tuesday, May 12, 1998)]
[Rules and Regulations]
[Pages 26063-26066]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-12512]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-111-AD; Amendment 39-10522; AD 98-10-10]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 and 767 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 747 and 767 series airplanes. 
This action requires a one-time inspection to confirm the installation 
of Teflon sleeves over certain electrical wires inside conduits 
installed in the fuel tanks; and corrective actions, if necessary. This 
amendment is prompted by a report of missing Teflon sleeves, which 
protect the wiring insulation from chafing. The actions specified in 
this AD are intended to prevent such chafing, which could eventually 
expose the electrical conductor creating the potential for arcing from 
the wire to the conduit, and consequent fuel tank fire/explosion.

DATES: Effective May 27, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 27, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before July 13, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114,

[[Page 26064]]

Attention: Rules Docket No. 98-NM-111-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    The service information referenced in this AD 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; or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Ed Hormel, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2681; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: On July 17, 1996, shortly after takeoff from 
John F. Kennedy International Airport in Jamaica, New York, a Boeing 
Model 747 series airplane was involved in an accident during which the 
center fuel tank exploded. Ensuing investigations of the cause of the 
accident have focused on the fuel tank explosion.
    A recent inspection of the main fuel tanks on a Model 747 series 
airplane indicated that the inner and outer Teflon sleeves were missing 
from wiring within the conduit of the aft boost pump to the number 4 
main fuel tank. The reason for the missing sleeves has not been 
determined. Missing Teflon sleeves could result in chafing of the wire 
insulation encasing the fuel pump wiring. These conditions, if not 
corrected, could eventually expose the electrical conductor creating 
the potential for arcing from the wire to the conduit, and consequent 
fuel tank fire/explosion.

Similar Airplanes

    The vibration environment and the conduit and wiring installations 
associated with fuel pumps in the wing fuel tanks of Model 747 and 767 
series airplanes are similar. Therefore, the FAA has determined that 
both models may be subject to the unsafe condition identified in this 
AD.

Related AD's

    The FAA has issued a number of AD's to address various fuel-tank 
related unsafe conditions on Boeing Model 747 series airplanes, 
including the following:
    <bullet> AD 79-05-04, amendment 39-3431 (44 FR 12636, March 8, 
1979). This AD was prompted by a report indicating that fuel pump wires 
had chafed through the insulation in an aluminum conduit inside an 
auxiliary fuel tank on a Model 747 series airplane. Electrical arcing 
from the chafed wire to the aluminum conduit had burned a hole in the 
conduit permitting fuel leakage; however, the arcing did not result in 
a fire or explosion. That AD requires discontinued use of the auxiliary 
fuel tanks unless Teflon sleeving is installed over the wire bundles in 
accordance with Boeing Alert Service Bulletin 747-28A2091, Revision 1, 
dated February 5, 1979.
    <bullet> AD 79-06-02, amendment 39-3439 (44 FR 16362, March 19, 
1979). Because the conduit and wiring installations for the auxiliary 
fuel tanks are similar to those of the number 1 and number 4 main fuel 
tanks on Model 747 series airplanes, an inspection of the boost pump 
wiring of the main fuel tank was conducted on other airplanes of this 
model. Although none of the wires inspected had worn completely through 
the insulation, chafing through 80 percent of the total insulation 
thickness was found on numerous wires. The reported chafing was 
attributed to vibration of the wires against the conduit wall. Based on 
these results, AD 79-26-02 was issued to require inspection, repair, 
and modification of the boost pump wires of the outboard main (number 1 
and number 4) fuel tanks on Model 747 series airplanes. Corrective 
actions involve replacing chafed wires, installing wire ties at equal 
intervals, and installing double-layer Teflon sleeves over the wires, 
in accordance with Boeing Alert Service Bulletin 747-28A2092, dated 
February 12, 1979.
    <bullet> AD 96-26-06, amendment 39-9870 (62 FR 304, January 1, 
1997). Following the 1996 accident, AD 96-26-06 was issued to require a 
one-time inspection in accordance with Boeing Alert Service Bulletin 
747-28A2201, dated December 19, 1996. The purpose of this inspection 
was to detect damage to the Teflon sleeving and wire bundles to the 
forward and aft boost pumps for the number 1 and number 4 main fuel 
tanks and to the auxiliary tank jettison pumps (if installed) on Model 
747 series airplanes equipped with aluminum conduits. At the time AD 
96-26-06 was issued, the FAA had determined that sleeving inside 
aluminum conduits was more susceptible to chafing and burn-through in 
the event of arcing than sleeving inside stainless steel conduits.
    <bullet> AD 97-26-07, amendment 39-10250 (62 FR 65352, December 12, 
1997). Based on damage reports from two operators that had replaced the 
aluminum conduits with stainless steel conduits and had found 
significant chafing on 48 percent of the airplanes checked, the FAA 
concluded that stainless steel conduit installations also should be 
inspected. Therefore, the FAA issued AD 97-26-07, which supersedes AD 
96-26-06 to expand the inspection requirements to include Model 747 
series airplanes having stainless steel conduits, and to add repetitive 
inspections of the Teflon sleeving on all Model 747 series airplanes to 
determine whether the sleeving would continue to provide a protective 
barrier after extended time in service.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Message M-7200-98-01080, 
dated March 18, 1998 (hereinafter refered to as the ``message''). The 
message describes procedures for a one-time inspection to confirm 
installation of Teflon sleeving over wiring in conduits in the boost 
pumps of the numbers 1 and 4 main fuel tanks on Boeing Model 747 series 
airplanes, and in the main and center wing tanks on Model 767 series 
airplanes; and corrective actions, if necessary. The corrective actions 
involve follow-on inspections, installation of Teflon sleeves, and 
replacement of damaged wiring and conduits. Accomplishment of the 
actions specified in the message is intended to adequately address the 
identified unsafe condition.
    The message refers to Boeing Alert Service Bulletin 747-28A2204 as 
an additional source of service information for accomplishment of the 
requirements of this AD.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design, this AD is 
being issued to prevent chafing of electrical wiring inside the 
conduits, which could eventually expose the electrical conductor 
creating the potential for arcing from the wire to the conduit, and 
consequent fuel tank fire/explosion. This AD requires accomplishment of 
the actions specified in the message described previously, except as 
described below. This AD also requires operators to send any damaged 
wires and conduits, and to submit a report to the FAA.

Differences Between the Rule and the Message

    Operators should note that, whereas the message provides a 
compliance time of 30 days, the rule requires compliance within 60 
days. Although the message recommends a 30-day compliance time,

[[Page 26065]]

the manufacturer, through a subsequent review of the number of affected 
airplanes, has advised the FAA that 30 days will be insufficient to 
accomplish the actions required by this AD on such a large fleet. The 
FAA has determined that a 60-day compliance time is appropriate in 
consideration of the safety implications of this AD, the size of the 
affected fleet, and the practical aspects of an orderly inspection 
within the allotted time.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 98-NM-111-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will not have substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

98-10-10 Boeing: Amendment 39-10522. Docket 98-NM-111-AD.

    Applicability: Model 747 series airplanes, line positions 0001 
through 1145 inclusive, that have not been inspected in accordance 
with AD 96-26-06, amendment 39-9870 (reference Boeing Alert Service 
Bulletin 747-28A2204, dated December 19, 1996), or AD 97-26-07, 
amendment 39-10250 (reference Boeing Alert Service Bulletin 747-
28A2204, Revision 1, dated October 30, 1997); and Model 767 series 
airplanes, line positions 001 through 689 inclusive, and 691; 
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 specific proposed actions to address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent chafing of the wire insulation inside conduits 
installed in the fuel tanks, which could eventually expose the 
electrical conductor creating the potential for arcing from the wire 
to the conduit, and consequent fuel tank fire/explosion, accomplish 
the following:
    (a) Within 60 days after the effective date of this AD, perform 
a one-time visual inspection to confirm installation of Teflon 
sleeves over the electrical wires to the boost pumps installed 
inside conduits in the numbers 1 and 4 main fuel tanks (for Model 
747 series airplanes), or in the main and center wing tanks (for 
Model 767 series airplanes), as applicable, in accordance with 
Boeing Message M-7200-98-01080, dated March 18, 1998.
    (b) If any Teflon sleeve is found to be missing during the 
inspection required by paragraph (a) of this AD, prior to further 
flight, inspect to detect damage to the wires, in accordance with 
Boeing Message M-7200-98-01080, dated March 18, 1998.
    (1) If no damage is found, prior to further flight, install a 
Teflon sleeve in accordance with the message.
    (2) If any damage is found, prior to further flight, inspect to 
detect damage to the conduits in accordance with the message.
    (i) If no damage is found, prior to further flight, replace any 
damaged wire and install a Teflon sleeve in accordance with the 
message.
    (ii) If any damage is found, prior to further flight, replace 
any damaged wire and conduit and install a Teflon sleeve, in 
accordance with the messsage.

    Note 2: Boeing Message M-7200-98-01080, dated March 18, 1998, 
refers to Boeing Alert Service Bulletin 747-28A2204 as an additional 
source of service information.

    (c) Within 10 days after finding any damage during any 
inspection required by paragraph (b) of this AD, send damaged wiring 
and conduits and submit a report to the Manager, Seattle Aircraft 
Certification Office (ACO), FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; fax (425) 227-
1181. The report must include the following:
    <bullet> The airplane model number;
    <bullet> The airplane line position;
    <bullet> The total number of hours time-in-service accumulated 
on the airplane;

[[Page 26066]]

    <bullet> The total number of flight cycles accumulated on the 
airplane;
    <bullet> A description of the area of the wiring where the 
sleeving was missing; and
    <bullet> A description of the damage found.

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.
    (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 ACO. 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.

    (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.
    (f) The actions shall be done in accordance with Boeing Message 
M-7200-98-01080, dated March 18, 1998. This incorporation by 
reference was approved by the Director of the Federal Register in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, 
Seattle, Washington 98124-2207. Copies may be inspected at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.
    (g) This amendment becomes effective on May 27, 1998.

    Issued in Renton, Washington, on May 5, 1998.
John J. Hickey,
 Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-12512 Filed 5-11-98; 8:45 am]
BILLING CODE 4910-13-U