AD 99-17-06

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A310 series airplanes, that requires repetitive inspections and tests to detect missing or damaged vespel bushes on the slat system universal joint assemblies of the left- and right-hand wings; and replacement of the universal joints with new joints, if necessary. This amendment also provides for an optional terminating modification for the repetitive inspection and test requirements. This amendment is prompted by a report of loose and migrated vespel bushes and partial cracking within unsupported bush areas found on the slat system universal joint assemblies. The actions specified by this AD are intended to prevent rupture of the universal joints, which could result in inadvertent movement of the slats, and consequent reduced controllability of the airplane.

Final rule.

99-17-06 AIRBUS INDUSTRIE: Amendment 39-11255. Docket 93-NM-125-AD.

Applicability: Model A310 series airplanes, except those on which Airbus Modification 10092 (Airbus Service Bulletin A310-27-2060, Revision 01, dated October 3, 1997) has been accomplished; 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 (d) 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 rupture of the universal joints, which could result in inadvertent movement of the slats, and consequent reduced controllability of the airplane, accomplish the following:

Inspections and Corrective Actions
(a) Prior to the accumulation of 15,000 total landings, or within 400 flight hours after the effective date of this AD, whichever occurs later, perform a visual inspection and an electrical continuity test to detect missing or damaged vespel bushes on the slat system universal joint assemblies of the left- and right-hand wings, in accordance with Airbus Service Bulletin A310-27-2061, dated November 4, 1992, or Revision 01, dated October 3, 1997. Repeat this inspection and test thereafter at intervals not to exceed 15,000 landings.

(b) If any vespel bushes are missing or damaged, prior to further flight, replace the universal joint with a newjoint in accordance with Airbus Industrie Service Bulletin A310-27- 2061, dated November 4, 1992, or Revision 01, dated October 3, 1997. After replacement, continue to repeat the inspection and test required by paragraph (a) of this AD at intervals not to exceed 15,000 landings.

Optional Terminating Modification
(c) Modification of the slat system universal joint and shaft assemblies in accordance with Airbus Service Bulletin A310-27-2060, Revision 01, dated October 3, 1997, constitutes terminating action for the repetitive inspection and test requirements of this AD.

Alternative Methods of Compliance
(d) 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.

NOTE 2: 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
(e) 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
(f) Except as provided by paragraph (c) of this AD, the actions shall be done in accordance with Airbus Service Bulletin A310-27-2061, dated November 4, 1992, or Airbus Service Bulletin A310-27-2061, Revision 01, dated October 3, 1997. 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 3: The subject of this AD is addressed in French airworthiness directive 92-275- 139(B)R1, dated December 17, 1997.

(g) This amendment becomes effective on September 22, 1999.

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 A310 series airplanes was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on October 14, 1998 (63 FR 55061). That action proposed to require repetitive inspections and tests to detect missing or damaged vespel bushes on the slat system universal joint assemblies of the left- and right-hand wings; and replacement of the universal joints with new joints, if necessary. That action also provided for an optional terminating modification for the repetitive inspection and test requirements.

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.

Support for the Proposal
One commenter supports the proposed rule.

Removal ofVisual Inspection (Manual Backlash Check) Requirement
In response to the original NPRM, two commenters request that paragraph (a) of the proposed AD be revised to remove the visual inspection, or "manual backlash check", to detect missing or damaged vespel bushes on the slat system universal joint assemblies of the left- and right-hand wings. One commenter states that the visual inspection is very unreliable and results are difficult to quantify. Further, the commenter states that the electrical continuity test that is also required by paragraph (a) of the proposed AD is sufficient in itself for ensuring the integrity of the universal joint and confirming the possibility of a missing vespel bushing.

Another commenter, the manufacturer, states that the manual backlash check is impractical and difficult to evaluate, thus the proposed AD requires inspecting in a way that is not feasible. This commenter states that the referenced Airbus and Lucas service bulletins are undergoingrevision to remove the procedures for the manual backlash check contained therein, and requests that the proposed AD refer to the later revisions, thus removing the requirement for the manual backlash check.

The FAA does not concur with the request to remove the requirement for visual inspection. The FAA acknowledges that results of the visual inspection may be difficult to assess reliably, as described in Lucas Service Bulletin 525A-27-618, dated October 5, 1992 (which is referenced in Airbus Service Bulletin A310-27-2061 as an additional source of service information). However, the visual inspection is intended to provide only an initial assessment for presence of vespel bushes and is to be followed by the electrical continuity test to finalize such a determination.

Since issuance of the original NPRM, Airbus Service Bulletin A310-27-2061, Revision 1, dated October 3, 1997, has been issued, and this revision was cited as an appropriate source of service information in the supplemental NPRM. This later revision still contains procedures for accomplishment of the visual inspection. Since no additional information has been provided by the manufacturer or vendor regarding the acceptability of eliminating the visual inspection, the FAA has determined that the visual inspection should be accomplished in addition to the electrical continuity test, as described in the Airbus service bulletin. No change is made to the final rule in this regard.

Correction of Typographical Error
One commenter notes that the preamble to the supplemental NPRM contains an incorrect reference to an Airbus Model A320 series airplane, rather than Model A310 series airplanes to which this proposed AD is applicable. The FAA acknowledges the error, however, because this section of the preamble to the supplemental NPRM is not restated in the final rule, no change to the AD is necessary.

Conclusion
After careful review of the available data, including the comments noted above, theFAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact
The FAA estimates that 41 airplanes of U.S. registry will be affected by this AD, that it will take approximately 20 work hours per airplane to accomplish the required inspection and test, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the inspection and test required by this AD on U.S. operators is estimated to be $49,200, or $1,200 per airplane, per inspection and test cycle.

The cost impact figure discussed above is 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.

Should an operator elect to accomplish the optional terminating modification provided by this AD action, it would take approximately 11 work hours to accomplish, at an average labor rate of $60 per work hour. Required parts would be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the optional terminating modification would be $660 per airplane.

Regulatory Impact
The regulations adopted herein will 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 final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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, on a 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: