[Federal Register Volume 63, Number 165 (Wednesday, August 26, 1998)]
[Proposed Rules]
[Pages 45423-45425]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-22819]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-29-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 adoption of a new airworthiness 
directive (AD) that is applicable to certain Airbus Model A320 series 
airplanes. This proposal would require repetitive inspections to detect 
fatigue cracking of the lower surface panel on the wing center box; and 
repair, if necessary. This proposal also would require modification of 
the lower surface panel on the wing center box, which constitutes 
terminating action for the repetitive inspections. This proposal is 
prompted by issuance of mandatory continuing airworthiness information 
by a foreign civil airworthiness authority. The actions specified by 
the proposed AD are intended to prevent fatigue cracking of the lower 
surface panel on the wing center box, which could result in reduced 
structural integrity of the airplane.

DATES: Comments must be received by September 25, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-29-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 the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2110; fax (425) 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 98-NM-29-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. 98-NM-29-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Direction Generale de l'Aviation Civile (DGAC), which is the 
airworthiness authority for France, notified the FAA that an unsafe 
condition may exist on certain Airbus Model A320 series airplanes. The 
DGAC advises that, during full-scale fatigue testing on a Model A320 
test article, fatigue cracking occurred at 109,217 simulated flights 
between frames 41 and 42 on the right and left sides of the lower 
surface panel on the wing center box. Such fatigue cracking, if not 
corrected, could result in reduced structural integrity of the 
airplane.

Explanation of Relevant Service Information

    Airbus has issued Service Bulletin A320-57-1082, Revision 01, dated 
December 10, 1997, which describes procedures for performing repetitive 
high frequency eddy current inspections to detect fatigue cracking of 
the lower surface panel on the wing center box; and repair, if 
necessary. Accomplishment of the repair would eliminate the need for 
the repetitive inspections of the repaired area.
    In addition, Airbus has issued Service Bulletin A320-57-1043, 
Revision 2, dated May 14, 1997, which describes procedures for 
modification of the lower surface panel on the wing center box. The 
modification involves shot peening of the external side of the lower 
surface panel near the fuel pump aperture where the thickness changes. 
Accomplishment of this modification also would eliminate the need for 
the repetitive inspections described in Airbus Service Bulletin A320-
57-1082, Revision 01.
    Accomplishment of the actions specified in these service bulletins 
is intended to adequately address the identified unsafe condition. The 
DGAC classified Airbus Service Bulletin A320-57-1082, Revision 01, as 
mandatory and issued French airworthiness directive 97-309-104(B), 
dated October 22, 1997, 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 
Sec. 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 require accomplishment of 
the actions specified in the service bulletins, except as discussed 
below. Accomplishment of the modification of the lower surface panel on 
the wing center box constitutes terminating action for the repetitive 
inspections.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, although Airbus Service Bulletin A320-
57-1082,

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Revision 01, dated December 10, 1997, specifies that the manufacturer 
may be contacted for disposition of certain repair conditions, this 
proposal would require the repair of those conditions to be 
accomplished in accordance with a method approved by either the FAA or 
the DGAC (or its delegated agent). In light of the type of repair that 
would be required to address the identified unsafe condition, and in 
consonance with existing bilateral airworthiness agreements, the FAA 
has determined that, for this proposed AD, a repair approved by either 
the FAA or the DGAC would be acceptable for compliance with this 
proposed AD.

Differences Between Proposed Rule and Foreign AD

    Operators should note that, unlike the procedures described in 
French airworthiness directive 97-309-104(B), dated October 22, 1997, 
this proposed AD would not permit further flight if fatigue cracks are 
detected on the lower surface panel of the wing center box. The FAA has 
determined that, because of the safety implications and consequences 
associated with such fatigue cracking, any subject lower surface panel 
that is found to be cracked must be repaired prior to further flight in 
accordance with a method approved by the FAA or the DGAC (or its 
delegated agent).
    In addition, the proposed AD would differ from the parallel French 
airworthiness directive in that it would mandate the accomplishment of 
the terminating action for the repetitive inspections. The French 
airworthiness directive provides for that action as optional.
    Mandating the terminating action is based on the FAA's 
determination 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 continual 
inspections, has led the FAA to consider placing less emphasis on 
inspections and more emphasis on design improvements. The proposed 
modification requirement is in consonance with these conditions.

Cost Impact

    The FAA estimates that 60 airplanes of U.S. registry would be 
affected by this proposed AD. It would take approximately 2 work hours 
per airplane to accomplish the proposed inspection, at an average labor 
rate of $60 per work hour. Based on these figures, the cost impact of 
the inspection proposed by this AD on U.S. operators is estimated to be 
$7,200, or $120 per airplane, per inspection cycle.
    It would take approximately 2 work hours per airplane to accomplish 
the modification, at an average labor rate of $60 per work hour. There 
are no parts necessary to accomplish the modification. Based on these 
figures, the cost impact of the modification proposed by this AD on 
U.S. operators is estimated to be $7,200, or $120 per airplane.
    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 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 adding the following new 
airworthiness directive:

    Airbus Industrie: Docket 98-NM-29-AD.

    Applicability: Model A320 series airplanes on which Airbus 
Modification 22418 (reference Airbus Service Bulletin A320-57-1043, 
Revision 2, dated May 14, 1997) 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 (f) 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 fatigue cracking of the lower surface panel on the 
wing center box, which could result in reduced structural integrity 
of the airplane, accomplish the following:
    (a) Except as provided by paragraph (e) of this AD: Prior to the 
accumulation of 20,000 total flight cycles, or within 60 days after 
the effective date of this AD, whichever occurs later, perform a 
high frequency eddy current inspection to detect fatigue cracking of 
the lower surface panel on the wing center box, in accordance with 
Airbus Service Bulletin A320-57-1082, Revision 01, dated December 
10, 1997. Repeat the eddy current inspection thereafter at intervals 
not to exceed 7,500 flight cycles until the actions required by 
paragraph (c) of this AD are accomplished.
    (b) Except as provided by paragraph (d) of this AD: If any 
cracking is detected during any inspection required by paragraph (a) 
of this AD, prior to further flight, repair in accordance with 
Airbus Service Bulletin A320-57-1082, Revision 01, dated December 
10, 1997. Accomplishment of the repair constitutes terminating 
action for the repetitive inspections for the repaired area only.
    (c) Prior to the accumulation of 25,000 total flight cycles, or 
within 60 days after the effective date of this AD, whichever occurs 
later: Perform a high frequency eddy current inspection to detect 
fatigue cracking of the lower surface panel on the wing center box, 
in accordance with Airbus Service Bulletin A320-57-1082, Revision 
01, dated December 10, 1997.
    (1) If no cracking is detected: Prior to further flight, modify 
the lower surface panel

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on the wing center box, in accordance with Airbus Service Bulletin 
A320-57-1043, Revision 2, dated May 14, 1997. Accomplishment of the 
modification constitutes terminating action for the requirements of 
this AD.
    (2) Except as provided by paragraph (d) of this AD, if any 
cracking is detected: Prior to further flight, repair in accordance 
with Airbus Service Bulletin A320-57-1082, Revision 01, dated 
December 10, 1997; and modify any uncracked area in accordance with 
Airbus Service Bulletin A320-57-1043, Revision 2, dated May 14, 
1997. Accomplishment of the repair of cracked area(s) and 
modification of uncracked area(s) constitutes terminating action for 
the requirements of this AD.
    (d) If any cracking is detected during any inspection required 
by paragraph (b) or (c)(2) of this AD, and the applicable service 
bulletin specifies to contact Airbus for an appropriate action: 
Prior to further flight, repair in accordance with a method approved 
by either the Manager, International Branch, ANM-116, FAA, Transport 
Airplane Directorate; or the Direction Generale de l'Aviation Civile 
(or its delegated agent).
    (e) The actions required by paragraph (a) of this AD are not 
required to be accomplished if the requirements of paragraph (c) of 
this AD are accomplished at the time specified in paragraph (a) of 
this AD.
    (f) 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, International Branch, ANM-116. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, International Branch, ANM-116.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.

    (g) 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.

    Note 3: The subject of this AD is addressed in French 
airworthiness directive 97-309-104(B), dated October 22, 1997.

    Issued in Renton, Washington, on August 19, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-22819 Filed 8-25-98; 8:45 am]
BILLING CODE 4910-13-P