Airworthiness Directives; Airbus Model A319, A320, and A321 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Airbus Model A319, A320, and A321 series airplanes. This proposal would require repetitive inspections of the sliding tube subassembly on the main landing gear (MLG) to detect cracks, and replacement of a cracked subassembly with a new subassembly. This proposal also would eventually require a more extensive, one-time inspection of the same area and corrective actions, if necessary; which would terminate 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 cracking of the MLG sliding tube subassembly, which could result in collapse of the MLG.

DATES:

Comments must be received by March 16, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-343-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 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 99-NM-343-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. 99-NM-343-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 A319, A320, and A321 series airplanes. The DGAC advises that, during a scheduled inspection of the main landing gear (MLG) on one airplane, two cracks were found in the base of the sliding tube. The cracks originated from the bore of the jacking dome bushing. The DGAC advises that a nondestructive test inspection may have been improperly performed causing local overheating between the jacking dome bushing and the sliding tube bore. This overheating increases the possibility of crack initiation. This condition, if not corrected, could result in collapse of the MLG.

Explanation of Relevant Service Information

Airbus has issued Service Bulletin A320-32-1189, dated December 23, 1998, which describes procedures for visual inspections of the MLG sliding tube subassembly for cracks, and corrective action, if necessary. Two separate inspections are described. The service bulletin describes procedures for repetitive visual inspections of the sliding tube subassembly around the area between the jacking dome bushing and the high pressure inflation valve, and between the jacking dome bushing and the hole for the lower electrical harness assembly; and procedures for replacing a cracked sliding tube subassembly with a new subassembly. The service bulletin also describes procedures for removal of the jacking dome, bushing, and harness supports, and a one-time visual inspection to detect cracking of the sliding tube subassembly in the area where the jacking dome bushing was removed.

Airbus has also revised the Aircraft Maintenance Manual to include cautions during accomplishment of the MLG nondestructive test inspection.

Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition. The DGAC classified the Airbus service bulletin as mandatory and issued French airworthiness directive 1999-358-137(B) R1, dated October 20, 1999, in order to ensure the continued airworthiness of these airplanes in France.

FAA's Conclusions

These airplane models are manufactured in France and are type certificated for operation in the United States under the provisions of § 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 Airbus service bulletins described previously, except as discussed below.

Differences Between NPRM and Service Bulletin/French Airworthiness Directive

The proposed compliance times and repetitive intervals (stated in flight hours) differ from those recommended by the manufacturer's service bulletin (stated to coincide with operators' “A” and “C” checks). However, because regularly scheduled maintenance intervals such as “A” checks and “C” checks may vary from operator to operator, there would be no assurance that the inspections would be accomplished during the maximum intervals proposed by this AD designed to maintain an adequate level of safety within the fleet. The compliance times in the proposed AD and the French airworthiness directive agree.

In addition, operators should note that, although the service bulletin 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.

Further, the applicability of this proposed AD differs from that of the French airworthiness directive, which excludes airplanes on which (1) the MLG sliding tubes have never been removed, (2) the MLG sliding tubes have never received an NDT (NDT2) inspection, and (3) the MLG sliding tubes have received an NDT (NDT2) inspection with the attaching hardware and bushing removed from the sliding tube. Because these conditions may not be easily determined, the applicability of this proposed AD would be limited to airplanes on which Airbus Service Bulletin A320-32-1189 has not been accomplished.

Cost Impact

The FAA estimates that 179 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 “Part A” (repetitive) inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the Part A inspection proposed by this AD on U.S. operators is estimated to be $10,740, or $60 per airplane, per inspection cycle.

It would take approximately 6 work hours per airplane to accomplish the proposed “Part B” (one-time) inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the Part B inspection proposed by this AD on U.S. operators is estimated to be $64,440, or $360 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 a substantial direct effect 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, it is determined that this proposal would not have federalism implications under Executive Order 13132.

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.