[Federal Register Volume 61, Number 177 (Wednesday, September 11, 1996)]
[Proposed Rules]
[Pages 47835-47838]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-23241]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-176-AD]
RIN 2120-AA64
Airworthiness Directives; Airbus Model A320 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the supersedure of an existing
airworthiness directive (AD), applicable to certain Airbus Model A320
series airplanes, that currently requires inspections to detect chafing
of the wire looms (bundles) in the wing and the horizontal stabilizer;
and repair or replacement, protection, and realignment, if necessary.
This proposal would require that those actions also be accomplished in
certain areas of the main landing gear (MLG) bays. This proposal also
would require installation of protective sleeves around the wire
bundles, and realignment of bundles that are not guided centrally into
the conduit end fittings, which constitutes terminating action for the
repetitive inspections. This proposal is prompted by a report that
electrical short circuiting could occur in the wire bundles in the MLG
bays. The actions specified by the proposed AD are intended to prevent
such electrical short circuiting due to chafing of the wire bundles in
the wing, horizontal stabilizer, or MLG bays.
DATES: Comments must be received by October 21, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-176-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.
The service information referenced in the proposed rule may be
obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707
Blagnac Cedex, France. This information may be examined at
[[Page 47836]]
the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: Tim Backman, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-2797; fax (206) 227-1149.
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.
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 95-NM-176-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-103, Attention: Rules
Docket No. 95-NM-176-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On September 30, 1992, the FAA issued AD 92-22-02, amendment 39-
8388 (57 FR 48957, October 29, 1992), applicable to certain Airbus
Model A320 series airplanes, to require inspections to detect chafing
of the wire looms (bundles) in the wing and the horizontal stabilizer;
and repair or replacement, protection, and realignment, if necessary.
That action was prompted by an incident in which short circuiting of a
wire bundle caused fire extinguishant to discharge and pop the circuit
breaker for a brake fan. The requirements of that AD are intended to
prevent electrical short circuiting due to chafing of the wire bundles
in the wing and the horizontal stabilizer.
Actions Since Issuance of Previous Rule
Since the issuance of that AD, the Direction Generale de l'Aviation
Civile (DGAC), which is the airworthiness authority for France, has
advised the FAA that chafing of the wire bundles and subsequent
electrical short circuiting also could occur in the main landing gear
(MLG) bays. This condition presents the same unsafe condition that was
addressed by AD92-22-02.
Additionally, the DGAC has advised that protection of the wire
bundle is necessary following any repair or replacement of a wire to
prevent further wire damage.
Explanation of Relevant Service Information
Airbus has issued Service Bulletin A320-24-1044, Revision 3, dated
March 12, 1993. Although Revision 3 of the service bulletin is
essentially the same as Revision 2, it adds procedures for repetitive
visual inspections of the wire bundles to detect damage, contact with
the end fittings of the protective conduit, and misalignment with
conduit end fittings in the MLG bays. The service bulletin recommends
that any damaged wire be repaired or replaced in accordance with
procedures described in the Aircraft Wiring Manual or the Aircraft
Maintenance Manual.
Airbus also has issued Service Bulletin A320-24-1045, Revision 3,
dated June 10, 1993. Among other things, this service bulletin
describes procedures for installation of protective sleeves around the
wire bundles, and realignment of bundles that are not guided centrally
into the conduit end fittings. Revision 3 of the service bulletin adds
procedures for accomplishment of these actions in the MLG bays.
Accomplishment of the protection and realignment in accordance with
Revision 3 of the service bulletin eliminates the need for the
repetitive visual inspections.
The DGAC classified these service bulletins as mandatory and issued
French airworthiness directive 91-182-020(B)R2, dated December 7, 1994,
in order to assure the continued airworthiness of these airplanes in
France.
FAA's Conclusions
This airplane model is manufactured in France and is type
certificated for operation in the United States under the provisions of
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and
the applicable bilateral airworthiness agreement. Pursuant to this
bilateral airworthiness agreement, the DGAC has kept the FAA informed
of the situation described above. The FAA has examined the findings of
the DGAC, reviewed all available information, and determined that AD
action is necessary for products of this type design that are
certificated for operation in the United States.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other airplanes of the same type design registered
in the United States, the proposed AD would supersede AD 92-22-02 to
continue to require inspections to detect chafing of the wire bundles
in the wing and the horizontal stabilizer; and repair or replacement,
protection, and realignment, if necessary. The proposed AD also would
require that these actions be accomplished in certain areas of the MLG
bays. Additionally, the proposed AD would require installation of
protective sleeves around the wire bundles, and realignment of bundles
that are not guided centrally into the conduit end fittings, which
constitutes terminating action for the repetitive inspections. The
actions would be required to be accomplished in accordance with the
service bulletins described previously.
Explanation of Requirement for Terminating Action
While the French AD and service bulletins allow flight to continue
as long as the wire bundles are inspected repetitively, this proposed
AD would require that protection and, if necessary, realignment of the
wire bundles be accomplished as terminating action for the repetitive
inspections. The FAA has determined that long term continued
operational safety will be better assured by modifications or design
changes to remove the source of the problem, rather than by repetitive
inspections. Long term inspections may not be providing the degree of
safety assurance necessary for the transport airplane fleet. This,
coupled with a better understanding of the human factors associated
with numerous repetitive inspections, has led the FAA to consider
placing less emphasis on special procedures and
[[Page 47837]]
more emphasis on design improvements. The proposed requirement for
realignment and protection of the wire bundles is in consonance with
these considerations.
In developing an appropriate compliance time for the proposed
requirement to protect the wire bundles, the FAA's intent is that these
actions be accomplished during a regularly scheduled maintenance visit
for the majority of the affected fleet, when the airplanes would be
located at a base where special equipment and trained personnel would
be readily available, if necessary. The FAA finds that 7,000 hours
time-in-service corresponds closely to the interval representative of
most of the affected operators' normal maintenance schedules. The FAA
considers that this interval will provide an acceptable level of
safety.
Cost Impact
There are approximately 30 Model A320 series airplanes of U.S.
registry that would be affected by this proposed AD.
The actions that are required currently by AD 92-22-02 take
approximately 31 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the cost
impact on U.S. operators of the actions currently required is estimated
to be $55,800, or $1,860 per airplane.
The inspections that are proposed in this AD action would take
approximately 31 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Based on these figures, the cost
impact on U.S. operators of the proposed inspection is estimated to be
$55,800, or $1,860 per airplane.
The installation that is proposed in this AD action would take
approximately 59 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. The cost for required parts would be
negligible. Based on these figures, the cost impact on U.S. operators
of the proposed installation is estimated to be $106,200, or $3,540 per
airplane.
The cost impact figures discussed above are based on assumptions
that no operator has yet accomplished any of the current or proposed
requirements of this AD action, and that no operator would accomplish
those actions in the future if this AD were not adopted.
Regulatory Impact
The regulations proposed herein would 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
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
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 removing amendment 39-8388 (57 FR
48957, October 29, 1992), and by adding a new airworthiness directive
(AD), to read as follows:
Airbus Industrie: Docket 95-NM-176-AD. Supersedes AD 92-22-02,
Amendment 39-8388.
Applicability: Model A320 series airplanes on which Airbus
Modification No. 22109 (Airbus Service Bulletin A320-24-1045,
Revision 3, dated June 10, 1993) has not been accomplished;
certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
otherwise 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 (h) 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 electrical short circuiting due to chafing of the
wire bundles in the wing, horizontal stabilizer, or main landing
gear (MLG) bay, accomplish the following:
Restatement of Requirements of AD 92-22-02
(a) For airplanes having manufacturer's serial numbers through
169 inclusive: Prior to the accumulation of 450 hours time-in-
service after December 3, 1992 (the effective date of AD 92-22-02,
amendment 39-8388), inspect the wire bundles in wing zones 574 and
674 through panels 574AB and 674AB to detect chafing or contact with
the end fittings of the protective conduit, in accordance with
Airbus Service Bulletin A320-24-1044, Revision 2, dated March 3,
1992, or Revision 3, dated March 12, 1993. Thereafter, repeat this
inspection at intervals not to exceed 450 hours time-in-service
until the inspection required by paragraph (c) of this AD is
accomplished.
(1) If any chafed or damaged wire is found, prior to further
flight, repair or replace it in accordance with the Airplane
Maintenance Manual or the Aircraft Wiring Manual.
(2) If any wire bundle is found in contact with the edge of the
conduit end fitting, or which might come in contact with the edge of
the conduit end fitting due to vibration in flight, prior to further
flight, realign and protect the bundle in accordance with Airbus
Service Bulletin A320-24-1045, Revision 2, dated April 12, 1992, or
Revision 3, dated June 10, 1993; or in accordance with the temporary
repair described in paragraph 2.B.(2)(b) of Airbus Service Bulletin
A320-24-1044, Revision 2, dated March 3, 1992, or Revision 3, dated
March 12, 1993.
(b) For airplanes having manufacturer's serial numbers through
169 inclusive: Prior to the accumulation of 1,500 hours time-in-
service after December 3, 1992, inspect the wire bundles in the wing
and horizontal stabilizer, excluding wing zones 574 and 674 through
panels 574AB and 674AB, to detect chafing or contact with the ending
fittings of the protective conduit, in accordance with Airbus
Service Bulletin A320-24-1044, Revision 2, dated March 3, 1992, or
Revision 3, dated March 12, 1993. Thereafter, repeat this inspection
at intervals not to exceed 3,500 hours time-in-service until the
inspection required by paragraph (d) of this AD is accomplished.
(1) If any chafed or damaged wire is found, prior to further
flight, repair or replace it in accordance with the Airplane
Maintenance Manual or the Aircraft Wiring Manual.
(2) If any wire bundle is found in contact with the edge of the
conduit end fitting, or which might come in contact with the edge of
the conduit end fitting due to vibration in flight, prior to further
flight, realign and protect the bundle in accordance with Airbus
Service Bulletin A320-24-1045, Revision 2,
[[Page 47838]]
dated April 12, 1992, or Revision 3, dated June 10, 1993; or in
accordance with the temporary repair described in paragraph
2.B.(6)(b) of Airbus Service Bulletin A320-24-1044, Revision 2,
dated March 3, 1992, or Revision 3, dated March 12, 1993.
New Requirements of This AD
(c) For all airplanes: Prior to the accumulation of 450 hours
time-in-service after the effective date of this AD, inspect the
wire bundles in wing zones 574 and 674 through panels 574AB and
674AB to detect damage, contact chafing, or contact with the end
fittings of the protective conduit, in accordance with Airbus
Service Bulletin A320-24-1044, Revision 2, dated March 3, 1992, or
Revision 3, dated March 12, 1993. Thereafter, repeat this inspection
at intervals not to exceed 450 hours time-in-service. Accomplishment
of this inspection terminates the inspections required by paragraph
(a) of this AD.
(1) If any chafed or damaged wire is found, prior to further
flight, accomplish the requirements of paragraphs (c)(1)(i) and
(c)(1)(ii) of this AD.
(i) Repair or replace the wire in accordance with the Airplane
Maintenance Manual or the Aircraft Wiring Manual. And
(ii) Protect the wire bundle in accordance with Airbus Service
Bulletin A320-24-1045, Revision 2, dated April 12, 1992, or Revision
3, dated June 10, 1993; or in accordance with the temporary repair
described in paragraph 2.B.(2)(b) of Airbus Service Bulletin A320-
24-1044, Revision 2, dated March 3, 1992, or Revision 3, dated March
12, 1993.
(2) If any wire bundle is found in contact with the edge of the
conduit end fitting, or which might come in contact with the edge of
the conduit end fitting due to vibration in flight, prior to further
flight, realign and protect the bundle in accordance with Airbus
Service Bulletin A320-24-1045, Revision 2, dated April 12, 1992, or
Revision 3, dated June 10, 1993; or in accordance with the temporary
repair described in paragraph 2.B.(2)(b) of Airbus Service Bulletin
A320-24-1044, Revision 2, dated March 3, 1992, or Revision 3, dated
March 12, 1993.
(d) For all airplanes: Prior to the accumulation of 1,500 hours
time-in-service after the effective date of this AD, inspect the
wire bundles in the wing and horizontal stabilizer, excluding wing
zones 574 and 674 through panels 574AB and 674AB, to detect chafing
or contact with the ending fittings of the protective conduit, in
accordance with Airbus Service Bulletin A320-24-1044, Revision 2,
dated March 3, 1992, or Revision 3, dated March 12, 1993.
Thereafter, repeat this inspection at intervals not to exceed 3,500
hours time-in-service. Accomplishment of this paragraph terminates
the inspections required by paragraph (b) of this AD.
(1) If any chafed or damaged wire is found, prior to further
flight, accomplish the requirements of paragraphs (d)(1)(i) and
(d)(1)(ii) of this AD.
(i) Repair or replace the wire in accordance with the Airplane
Maintenance Manual or the Aircraft Wiring Manual. And
(ii) Protect the wire bundle in accordance with Airbus Service
Bulletin A320-24-1045, Revision 2, dated April 12, 1992, or Revision
3, dated June 10, 1993; or in accordance with the temporary repair
described in paragraph 2.B.(6)(b) of Airbus Service Bulletin A320-
24-1044, Revision 2, dated March 3, 1992, or Revision 3, dated March
12, 1993.
(2) If any wire bundle is found in contact with the edge of the
conduit end fitting, or which might come in contact with the edge of
the conduit end fitting due to vibration in flight, prior to further
flight, realign and protect the bundle in accordance with Airbus
Service Bulletin A320-24-1045, Revision 2, dated April 12, 1992, or
Revision 3, dated June 10, 1993; or in accordance with the temporary
repair described in paragraph 2.B.(6)(b) of Airbus Service Bulletin
A320-24-1044, Revision 2, dated March 3, 1992, or Revision 3, dated
March 12, 1993.
(e) For all airplanes: Prior to the accumulation of 1,500 hours
time-in-service after the effective date of this AD, inspect the
wire bundles in the MLG bays to detect chafing or contact with the
end fittings of the protective conduit, in accordance with Airbus
Service Bulletin A320-24-1044, Revision 3, dated March 12, 1993.
Thereafter, repeat this inspection at intervals not to exceed 3,500
hours time-in-service.
(1) If any chafed or damaged wire is found, prior to further
flight, accomplish the requirements of paragraphs (e)(1)(i) and
(e)(1)(ii) of this AD.
(i) Repair or replace the wire in accordance with the Airplane
Maintenance Manual or the Aircraft Wiring Manual. And
(ii) Protect the wire bundle in accordance with Airbus Service
Bulletin A320-24-1045, Revision 3, dated June 10, 1993; or in
accordance with the temporary repair described in paragraph
2.B.(6)(b) of Airbus Service Bulletin A320-24-1044, Revision 3,
dated March 12, 1993.
(2) If any wire bundle is found in contact with the edge of the
conduit end fitting, or which might come in contact with the edge of
the conduit end fitting due to vibration in flight, prior to further
flight, realign and protect the bundle in accordance with Airbus
Service Bulletin A320-24-1045, Revision 3, dated June 10, 1993; or
in accordance with the temporary repair described in paragraph
2.B.(6)(b) of Airbus Service Bulletin A320-24-1044, Revision 3,
dated March 12, 1993.
(f) If a temporary repair over a damaged length of wire bundle
is accomplished in accordance with paragraph (a)(2), (b)(2), (c)(2),
(d)(2), or (e)(2) of this AD: Prior to the accumulation of 450 hours
time-in-service, replace the temporary repair with a protective
sleeve around the wire bundle, and realign the bundle if it is not
guided centrally into the conduit end fittings. Accomplish these
actions in accordance with Airbus Service Bulletin A320-24-1045,
Revision 3, dated June 10, 1993. Accomplishment of these actions
terminates the repetitive inspections required by paragraph (c),
(d), or (e) of this AD, as applicable.
Note 2: Accomplishment of the actions in accordance with Airbus
Service Bulletin A320-24-1045, Revision 2, dated April 12, 1992, is
acceptable for compliance with the requirements of paragraph (f) of
this AD for the areas specified in paragraphs (c) and (d) of this
AD.
(g) For all airplanes: Prior to the accumulation of 7,000 hours
time-in-service after the effective date of this AD, install
protective sleeves around the wire bundles, and realign any bundle
that is not guided centrally into the conduit end fittings, in wing
zones 574 and 674 through panels 574AB and 674AB, in the wing and
horizontal stabilizer, excluding wing zones 574 and 674 through
panels 574AB and 674AB, and in the MLG bays, in accordance with
Airbus Service Bulletin A320-24-1045, Revision 3, dated June 10,
1993. Accomplishment of these actions constitutes terminating action
for the repetitive inspections required by this AD.
Note 3: Accomplishment of the actions in accordance with Airbus
Service Bulletin A320-24-1045, Revision 2, dated April 12, 1992, is
acceptable for compliance with the requirements of paragraph (g) of
this AD for the areas specified in paragraphs (c) and (d) of this
AD.
(h) 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, Standardization Branch, ANM-113,
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,
Standardization Branch, ANM-113.
Note 4: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(i) 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 5, 1996.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-23241 Filed 9-10-96; 8:45 am]
BILLING CODE 4910-13-U