[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]


-----------------------------------------------------------------------


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).

-----------------------------------------------------------------------

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