[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:
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.
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.
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.
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:
The airplane model number;
The airplane line position;
The total number of hours time-in-service accumulated
on the airplane;
[[Page 26066]]
The total number of flight cycles accumulated on the
airplane;
A description of the area of the wiring where the
sleeving was missing; and
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
