AD 96-21597

[Federal Register Volume 61, Number 166 (Monday, August 26, 1996)] [Proposed Rules] [Pages 43687-43689] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 96-21597]

======================================================================== Proposed Rules Federal Register ________________________________________________________________________ This section of the FEDERAL REGISTER contains notices to the public of the proposed issuance of rules and regulations. The purpose of these notices is to give interested persons an opportunity to participate in the rule making prior to the adoption of the final rules. ========================================================================

Federal Register / Vol. 61, No. 166 / Monday, August 26, 1996 / Proposed Rules

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-47-AD] RIN 2120-AA64

Airworthiness Directives; Airbus Model A320-111, -211, -212, and -231 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 A320-111, - 211, -212, and -231 series airplanes. This proposal would require repetitive inspections to detect cracks of the rear bracket attached to the outboard rib of the shroud boxes and the surfaces of the lugs adjacent to the bushes, and replacement, if necessary. This proposal also would require replacement of the outboard aft brackets of the shroud boxes with modified brackets that have floating boxes, which would terminate the repetitive inspections. This proposal is prompted by a report that the lug of the rear outboard bracket failed due to fatigue. The actions specified by the proposed AD are intended to prevent fatigue-related cracking in the subject lug, and the consequent failure of this lug; this condition could result in the loss of the shroud box, and, consequently, lead to reduced controllability of the airplane.

DATES: Comments must be received by October 4, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 96-NM-47-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: Charles Huber, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-2589; 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-47-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-47-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, recently notified the FAA that an unsafe condition may exist on certain Airbus Model A320-111, -211, - 212, and -231 series airplanes. The DGAC advises that it has received a report indicating that, during major fatigue testing on a Model A320 fatigue test wing, the lug of the rear outboard bracket failed at 85,714 simulated flights. This failure was caused by the movement between the shroud box, overwing panel, and the torque box. Such movement applied a longitudinal load to the outboard aft bracket, which resulted in the failure of the lug. Fatigue-related cracking in the subject lug could cause its failure. If the lug fails, the resultant loss of the shroud box could result in reduced controllability of the airplane.

Explanation of Relevant Service Information

Airbus has issued Service Bulletin A320-57-1034, Revision 2, dated September 8, 1995. The service bulletin describes procedures for repetitive visual inspections to detect cracks of the rear bracket attached to the outboard rib of the shroud boxes and the surfaces of the lugs adjacent to the bushes, and replacement of the bracket with a modified bracket, if any crack is detected. The DGAC classified this service bulletin as mandatory and issued French airworthiness directive 95-100-068(B), dated May 24, 1995, in order to assure the continued airworthiness of these airplanes in France. In addition, Airbus has issued Service Bulletin A320-57-1035, Revision 4, dated February 22, 1994, which describes procedures for replacement of the outboard aft brackets of the shroud boxes with modified brackets that have floating boxes. The modified brackets will eliminate the longitudinal loads being applied to the outboard aft brackets. Accomplishment of this replacement would eliminate the need for repetitive inspections.

FAA's Conclusions

This airplane model is manufactured in France and is type certificated for operation in the United States under the

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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 repetitive visual inspections to detect cracks of the rear bracket attached to the outboard rib of the shroud boxes and the surfaces of the lugs adjacent to the bushes, and replacement, if necessary. The proposed AD also would require replacement of the outboard aft brackets of the shroud boxes with modified brackets with floating boxes, which would constitute terminating action for the repetitive inspection requirements. The actions would be required to be accomplished in accordance with the service bulletins described previously.

Differences Between the Proposal and the Related French AD

This proposed rule would differ from the parallel French airworthiness directive 95-100-068(B), in that it would mandate the accomplishment of the terminating action for the repetitive inspections. The French airworthiness directive provides 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 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 requirement to accomplish the terminating action is in consonance with these considerations. The proposed rule also would differ from the parallel French airworthiness directive in that its applicability would include, in addition to other airplanes, Model A320-212 series airplanes. Since issuance of the French airworthiness directive, Airbus has issued Revision 2 of Service Bulletin A320-57-1034 (described above), which revises the effectivity listing of Revision 1 of that service bulletin by including Model A320-212 series airplanes. (The French AD references this service bulletin as the appropriate source of service information; however, does not reference any particular revision level.) The FAA has determined that Model A320-212 series airplanes are subject to the addressed unsafe condition.

Cost Impact

The FAA estimates that 70 Airbus Model A320-111, -211, -212, and - 231 series airplanes of U.S. registry would be affected by this proposed AD. It would take approximately 1 work hour 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 $4,200, or $60 per airplane, per inspection cycle. It would take approximately 35 work hours per airplane to accomplish the proposed modification, at an average labor rate of $60 per work hour. Required parts would cost approximately $2,170 per airplane. Based on these figures, the cost impact of the modification proposed by this AD on U.S. operators is estimated to be $298,900, or $4,270 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 USC 106(g), 40113, 44701.

Sec. 39.13 [Amended]

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

Airbus Industrie: Docket 96-NM-47-AD.

Applicability: Model A320-111, -211, -212, and -231 series airplanes, as listed in Airbus Service Bulletin A320-57-1034, Revision 2, dated September 8, 1995; 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 otherwise 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 (c) 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-related cracking in the shroud box attachment lug, which could result in the loss of the shroud box, and, consequently, lead to reduced controllability of the airplane, accomplish the following: (a) Prior to the accumulation of 17,000 total landings, or within 12 months after the effective date of this AD, whichever occurs later, perform a detailed visual inspection to detect cracks of the rear bracket attached to the outboard rib of the shroud boxes and the surfaces of the lugs adjacent to the bushes, in accordance with Airbus Service Bulletin

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A320-57-1034, Revision 2, dated September, 8, 1995.

Note 2: Inspections accomplished prior to the effective date of this amendment in accordance with Airbus Service Bulletin A320-57- 1034, Revision 1, dated August 24, 1992, are considered acceptable for compliance with the requirements of paragraph (a) of this AD.

(1) If no crack is detected, repeat the visual inspection thereafter at intervals specified in paragraph (a)(1)(i) or (a)(1)(ii), as applicable. (i) For Model A320-100 series airplanes: Repeat at intervals not to exceed 6,000 landings. (ii) For Model A320-200 series airplanes: Repeat at intervals not to exceed 4,800 landings. (2) If any crack is detected, prior to further flight, replace the bracket with a modified bracket, in accordance with Airbus Service Bulletin A320-57-1035, Revision 4, dated February 22, 1994. Accomplishment of this replacement terminates the requirements of this AD for that bracket. (b) Within 4 years following accomplishment of paragraph (a) of this AD, replace the outboard aft brackets of the shroud boxes with modified brackets that have floating boxes, in accordance with Airbus Service Bulletin A320-57-1035, Revision 4, dated February 22, 1994. Accomplishment of this replacement constitutes terminating action for the repetitive inspections requirements of paragraph (a) of this AD. (c) 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.

(d) 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 August 19, 1996. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 96-21597 Filed 8-23-96; 8:45 am] BILLING CODE 4910-13-U