AD 2000-11-09

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A319, A320, and A321 series airplanes, that requires 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 amendment also eventually requires a more extensive, one-time inspection of the same area and corrective actions, if necessary; which terminates the repetitive inspections. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent cracking of the MLG sliding tube subassembly, which could result in collapse of the MLG.

Final rule.

2000-11-09 AIRBUS: Amendment 39-11757. 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 been accomplished; and except those on which it can be shown that one of the following conditions has been met (also see NOTE 1):

(1) The main landing gear (MLG) sliding tubes have never been removed from the airplane;

(2) A magnetic particle non-destructive test (NDT2) inspection has never been accomplished on any of the MLG sliding tubes installed on the airplane; or

(3) If an NDT2 inspection has been accomplished on any of the MLG sliding tubes installed on the airplane, it was accomplished only after removal of the attaching hardware and bushings.

NOTE 1: Operators should note that complete maintenance records for the life of each MLG sliding tube are necessaryin order to make a definitive determination of whether any condition specified in the Applicability of the AD has been met.

NOTE 2: 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:

Inspections

(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.

NOTE 3: 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 terminatingaction 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 G n rale 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. 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 4: 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 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.

Incorporation by Reference

(e) Except as required by paragraph (b)(2), the actions shall be done in accordance with Airbus Service Bulletin A320-32-1189, dated December 23, 1998. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 5: The subject of this AD is addressed in French airworthiness directive 1999-358-137(B) R1, dated October 20, 1999.

(f) This amendment becomes effective on July 6, 2000.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Airbus Model A319, A320, and A321 series airplanes was published in the Federal Register on February 15, 2000 (65 FR 7465). That action proposed to 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. That action also proposed to eventually require a more extensive, one-time inspection of the same area and corrective actions, if necessary; which would terminate the repetitive inspections.

Comments Received
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Previous Inspections of MLG Sliding Tubes
Two commenters request that the applicability of the proposed ADbe revised to exclude airplanes on which certain conditions regarding the MLG sliding tubes are met. Specifically, the commenters request that airplanes be excluded if it can be determined that (1) the MLG sliding tubes have never been removed; (2) a magnetic particle non-destructive test (NDT2) inspection has never been accomplished on the installed MLG sliding tubes; or, (3) an NDT2 inspection has been accomplished on the installed MLG sliding tubes only after removal of attaching hardware and bushings. One commenter states that, contrary to the assertion in the proposed AD that these conditions cannot be easily determined, each operator is required to track such information for its airplanes. The commenter notes that, since an MLG sliding tube is a safe life-limited item, operators are required to maintain complete records of maintenance and overhaul. And, since the NDT2 inspection can be performed only in a shop environment, there should be no concern that such an inspection could have occurred "on-wing," without generation of proper maintenance records.

The FAA acknowledges that operators are required to maintain status records for each safe life-limited part with regard to the life limits of that part, i.e., hours or cycles of operation. However, not all operators maintain complete maintenance records for the life of the part, and such records would be necessary in order to make a definitive determination of the conditions defined above. The FAA has no objection to revising the applicability of the AD to exclude those airplanes on which one of these conditions can be definitively shown. The FAA has revised the applicability accordingly, and has added a "NOTE" to the final rule to specify that complete maintenance records are considered necessary in order to determine whether one of the above conditions has been met.

Exemption from Requirements of AD
One commenter, an operator, states that its airplanes have never been subjected to an NDT2 inspection (as referenced in Airbus Service Bulletin A320-32-1189, dated December 23, 1998), and hence are exempt from the repetitive inspections required by the proposed AD.

The FAA considers that reiteration of the requirements of the specified applicability of the proposed AD is necessary. The commenter is referring to a determination that an NDT2 inspection has never been accomplished [as described in condition (2) above] on its airplanes. All operators should be aware that the applicability of this AD (or any other AD) takes precedence over the effectivity listed in the referenced service bulletin. The exemption declared by the commenter, based on the information in the service bulletin, was NOT included in the applicability of the proposed AD, for reasons described in the "Differences" section of the preamble of the proposed AD. Therefore, the commenter was indeed subject to the requirements of the AD with the applicability as proposed. However, since the applicability of thefinal rule has been revised, as discussed above, the commenter may now reevaluate its determination of affected airplanes based on the applicability specified in the final rule.

Revision to Applicability of AD
One commenter states that the applicability of the proposed AD is confusing, and suggests that it be revised to include airplanes "only if the initial issue of Messier-Dowty SB 200-32-250 has been accomplished." (The original Messier-Dowty service bulletin called for an NDT2 inspection without specifying removal of the jacking dome bushings. If the jacking dome bushings were not removed, high temperature damage could have occurred to the MLG bore and bushings.) The commenter states that Airbus Service Bulletin A320-32-1189, dated December 23, 1998, was issued to alert operators of potential cracking that can occur if the NDT2 inspection procedures in the original Messier-Dowty service bulletin were used.

The FAA does not concur with limiting the applicability as suggested, due to potential difficulties in determining the complete inspection history of installed MLG sliding tubes, as described previously. However, the FAA has determined that an inadvertent error in the proposed applicability may have created confusion. The applicability of the proposed AD includes airplanes "...except those on which Airbus Service Bulletin A320-32-1189, dated December 23, 1998, has not been accomplished." Since the actions described in Airbus Service Bulletin A320-32-1189 are actually required by this AD, the FAA's intent in the proposed applicability was to exclude airplanes on which all actions described in Service Bulletin A320-32-1189 have been accomplished. Therefore, the FAA has determined that the applicability should have read "...except those on which Airbus Service Bulletin A320-32-1189, dated December 23, 1998, has been accomplished." The final rule has been revised accordingly.

Conclusion
After careful review of the available data, includingthe comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the change described previously. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact
The FAA estimates that 179 airplanes of U.S. registry will be affected by this AD.

It will take approximately 1 work hour per airplane to accomplish the required "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" (repetitive) inspection on U.S. operators is estimated to be $10,740, or $60 per airplane, per inspection cycle.

It will take approximately 6 work hours per airplane to accomplish the required "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" (one-time) inspection on U.S. operators is estimatedto 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 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 adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, ona substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: