[Federal Register Volume 62, Number 13 (Tuesday, January 21, 1997)]
[Proposed Rules]
[Pages 2982-2984]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1352]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-105-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 modification of an area on the 
front spar of the wing center section by installing shims and new 
fasteners to reinforce pressure floor fittings. This proposal is 
prompted by a report from the manufacturer indicating that full-scale 
fatigue testing on the test model revealed fatigue cracking in this 
area. The actions specified by the proposed AD are intended to prevent 
fatigue cracking in this area, which can reduce the structural 
integrity of fuselage frame 36 and the wing center section.

DATES: Comments must be received by February 21, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-105-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

[[Page 2983]]

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: 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 96-NM-105-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. 96-NM-105-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Direction Generale de l'Aviation (DGAC), which is the 
airworthiness authority for France, recently notified the FAA that an 
unsafe condition may exist on certain Airbus Model A320 series 
airplanes. The DGAC advises that it has received a report from the 
manufacturer indicating that full-scale fatigue testing on the test 
model revealed fatigue cracking in the rib flange on the front spar 
side of the wing center section. This cracking, which occurred at 
83,550 simulated flights, was located perpendicular to vertical posts 
at fuselage frame 36, and began at the vertical fillets of the rib 
flange. Such fatigue cracking, if not prevented, could result in 
reduced structural integrity of fuselage frame 36 and the wing center 
section.

Explanation of Relevant Service Information

    Airbus has issued Service Bulletin A320-57-1013, Revision 1, dated 
September 29, 1992, which describes procedures for modification of an 
area on the front spar of the wing center section by installing shims 
and new fasteners to reinforce pressure floor fittings. The DGAC 
classified this service bulletin as mandatory and issued French 
airworthiness directive (C/N) 95-098-066(B), dated May 24, 1995, 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 require modification of an 
area on the front spar of the wing center section by installing shims 
and new fasteners to reinforce pressure floor fittings. The actions 
would be required to be accomplished in accordance with the service 
bulletin described previously.

Cost Impact

    The FAA estimates that 5 Airbus Model A320 series airplanes of U.S. 
registry would be affected by this proposed AD.
    It would take approximately 13 work hours per airplane to 
accomplish the proposed actions, at an average labor rate of $60 per 
work hour. Required parts would cost approximately $576 per airplane. 
Based on these figures, the cost impact of the proposed AD on U.S. 
operators is estimated to be $6,780, or $1,356 per airplane.
    The cost impact figure discussed above is 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.

[[Page 2984]]

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Airbus Industrie: Docket 96-NM-105-AD.

    Applicability: Model A320 airplanes as listed in Airbus Service 
Bulletin A320-57-1013, Revision 1, dated September 29, 1992; 
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 (b) 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 in the rib flange on the front spar 
side of the wing center section, and consequent reduced structural 
integrity of fuselage frame 36 and the wing center section, 
accomplish the following:
    (a) Prior to the accumulation of 16,000 total landings, or 
within 3 months after the effective date of this AD, whichever 
occurs later, modify the rib flange on the front spar of the wing 
center section by installing shims and new fasteners to reinforce 
pressure floor fittings, in accordance with Airbus Service Bulletin 
A320-57-1013, Revision 1, dated September 29, 1992.

    Note 2: Modification of the rib flange accomplished prior to the 
effective date of this AD in accordance with Airbus Service Bulletin 
A320-57-1013, dated April 12, 1989, is considered acceptable for 
compliance with the modification required by this AD.

    (b) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (c) 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 January 3, 1997.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-1352 Filed 1-17-97; 8:45 am]
BILLING CODE 4910-13-U