Federal Aviation Administration, DOT.
Notice of proposed rulemaking (NPRM).
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.
Comments must be received by March 16, 2000.
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.Start Further Info
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.End Further Info End Preamble Start Supplemental Information
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. Start Printed Page 7466
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.
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.
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.
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 Start Printed Page 7467contacting the Rules Docket at the location provided under the caption ADDRESSES.Start List of Subjects
List of Subjects in 14 CFR Part 39
- Air transportation
- Aviation 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:Start Part
PART 39—AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
2. Section 39.13 is amended by adding the following new airworthiness directive:
Airbus: Docket 99-NM-343-AD.
Applicability: Model A319, A320, and A321 series airplanes; manufacturer serial numbers through 0875 inclusive; certificated in any category; except those on which Airbus Service Bulletin A320-32-1189, dated December 23, 1998, has not been accomplished.
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 (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 cracking of the sliding tube subassembly of the main landing gear (MLG), which could result in collapse of the MLG, accomplish the following:
(a) Within 500 flight hours after the effective date of this AD, perform a detailed visual inspection to detect cracking of the left-hand and right-hand MLG sliding tube subassemblies, in accordance with paragraph 2.B.(1) of the Accomplishment Instructions of Airbus Service Bulletin A320-32-1189, dated December 23, 1998.
(1) If no crack is found, repeat the inspection at intervals not to exceed 500 flight hours, until the requirements of paragraph (b) of this AD have been accomplished.
(2) If any crack is found, prior to further flight, replace the sliding tube subassembly with a new subassembly, in accordance with the service bulletin. Thereafter, repeat the inspection at intervals not to exceed 500 flight hours, until the requirements of paragraph (b) of this AD have been accomplished.
For the purposes of this AD, a detailed visual inspection is defined as: “an intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
(b) Within 15 months after the effective date of this AD: Remove the jacking dome, the stop washer, the jacking dome bushing, and the harness supports; and perform detailed visual inspections to detect discrepancies (including cracking of the left and right MLG sliding tube subassemblies, and overheat damage of the jacking dome bushing), in accordance with paragraph 2.B.(2) of the Accomplishment Instructions of Airbus Service Bulletin A320-32-1189, dated December 23, 1998. Accomplishment of the requirements of this paragraph constitutes terminating action for the requirements of paragraph (a) of this AD.
(1) If no discrepancy is found, prior to further flight, install a new stop washer and jacking dome bushing, in accordance with the service bulletin. No further action is required by this AD.
(2) If any discrepancy is found, prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the Direction Generale de l'Aviation Civile (DGAC) (or its delegated agent). For a repair method to be approved by the Manager, International Branch, ANM-116, as required by this paragraph, the Manager's approval letter must specifically reference this AD.
Alternative Methods of Compliance
(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, International Branch, ANM-116, 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, International Branch, ANM-116.
Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.
Special Flight Permits
(d) Special flight permits may be issued in accordance with §§ 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.
The subject of this AD is addressed in French airworthiness directive 1999-358-137(B) R1, dated October 20, 1999.
Issued in Renton, Washington, on February 9, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 00-3533 Filed 2-14-00; 8:45 am]
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