AD 98-18-02

This amendment supersedes an existing airworthiness directive (AD), applicable to all Airbus Industrie Model A300-600 series airplanes, that currently requires inspections to detect cracks in the center spar sealing angles adjacent to the pylon rear attachment and in the adjacent butt strap and skin panel, and correction of discrepancies. This amendment requires that the initial inspections be accomplished at reduced thresholds. This action also limits the applicability of the existing AD. This amendment is prompted by reports of cracking in the vertical web of the center spar sealing angles of the wing. The actions specified by this AD are intended to prevent crack formation in the sealing angles; such cracks could rupture and lead to subsequent crack formation in the bottom skin of the wing, and resultant reduced structural integrity of the center spar section of the wing.

Final rule.

98-18-02 AIRBUS INDUSTRIE: Amendment 39-10718. Docket 95-NM-200-AD. Supersedes AD 93-23-07, Amendment 39-8741.

Applicability: Model A300-600 series airplanes, as listed in Airbus Service Bulletin A300-57-6027, Revision 2, dated September 13, 1994; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been 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 (g) 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.

NOTE 2: Paragraphs (a) and (b) of this AD restate the requirements for initial and repetitive inspections contained in paragraphs (a) and (c) of AD 93-23-07. Therefore, for operators that have previously accomplished at least the initial inspection in accordance with AD 93-23-07, paragraphs (c) and (d) of this AD require that the next scheduled inspection be performed within 6,000 landings or 12,600 flight hours, whichever occurs first, after the last inspection performed in accordance with paragraph (a) or (c) of AD 93-23-07, or within 500 landings after the effective date of this AD, whichever occurs later.

To prevent crack formation in the sealing angles, which could rupture and lead to subsequent crack formation in the bottom skin of the wing, and resultant reduced structural integrity of the center spar section of the wing, accomplish the following:

RESTATEMENT OF CERTAIN REQUIREMENTS OF AD 93-23-07:
(a) For those airplanes on which the modification described in Airbus Repair Drawing R571-40588 has not been accomplished: Perform high frequency eddy current (HFEC) inspections to detect cracks in the center spar sealing angles adjacent to Rib 8, in accordance with Airbus Industrie Service Bulletin No. A300-57-6027, dated October 8, 1991, or Revision 2, dated September 13, 1994, at the time specified in paragraph (a)(1), (a)(2), or (a)(3) of this AD, as applicable. After the effective date of this AD, only Revision 2 of the service bulletin shall be used.

(1) For airplanes that have accumulated less than 12,000 total landings as of January 5, 1994 (the effective date of AD 93-23-07, amendment 39-8741): Prior to the accumulation of 12,000 total landings or within 2,000 landings after January 5, 1994, whichever occurs later; and thereafter at intervals not to exceed 6,000 landings until the inspections required by paragraph (c) of this AD are accomplished.

(2) For airplanes that have accumulated 12,000 total landings or more, but less than 14,000 total landings as of January 5, 1994: Prior to the accumulation of 14,000 total landings or within 2,000 landings after January 5, 1994, whichever occurs later; and thereafter at intervals not to exceed 6,000 landings until the inspections required by paragraph (c) of this AD are accomplished.

(3) For airplanes that have accumulated 14,000 total landings or more as of January 5, 1994: Prior to the accumulation of 500 landings after January 5, 1994; and thereafter at intervals not to exceed 6,000 landings until the inspections required by paragraph (c) of this AD are accomplished.

(b) For those airplanes on which the modification specified in Airbus Repair Drawing R571-40588 has been accomplished: Prior to the accumulation of 15,000 landings after accomplishing the modification, or within 500 landings after January 5, 1994, whichever occurs later, perform a HFEC inspection to detect cracks in the center spar sealing angles adjacent to Rib 8, in accordance with Airbus Industrie Service Bulletin No. A300-57-6027, dated October 8, 1991, or Revision 2, dated September 13, 1994. Thereafter, repeat this inspection at intervals not to exceed 6,000 landings until the inspection required by paragraph (d) of this AD is accomplished.

NEW REQUIREMENTS OF THIS AD:
(c) For those airplanes on which Airbus Modification 08609H5276 (Airbus Service Bulletin A300-57-6033), or the modification specified in Airbus Repair Drawing R571-40588 or R571-40942, has not been accomplished: Perform HFEC inspections to detect cracks in the center spar sealing angles adjacent to Rib 8, in accordance with Airbus Industrie Service Bulletin A300-57-6027, Revision 2, dated September 13, 1994, at the later of the times specified in paragraph (c)(1) or (c)(2), as applicable, and paragraph (c)(3) of this AD. Repeat the inspection thereafter at intervals not to exceed 6,000 landings or 12,600 flight hours, whichever occurs first. Accomplishment of these inspections terminates the requirements of paragraph (a) of this AD.

(1) For airplanes on which HFEC inspections have not been accomplished in accordance with AD 93-23-07: Prior to the accumulation of 10,600 total landings or 22,260 total flight hours, whichever occurs first.

(2) For airplanes on which HFEC inspections have been accomplished in accordance with AD 93-23-07: Within 6,000 landings or 12,600 flight hours, whichever occurs first, after accomplishment of the last inspection performed in accordance with the requirements of paragraph (a) of this AD.

(3) Within 500 landings after the effective date of this AD.

(d) For those airplanes on which Airbus Modification 08609H5276 (Airbus Service Bulletin A300-57-6033) or the modification specified in Airbus Repair Drawing R571-40588 or R571-40942 has been accomplished: Perform a HFEC inspection to detect cracks in the centerspar sealing angles adjacent to Rib 8, in accordance with Airbus Industrie Service Bulletin No. A300-57-6027, Revision 2, dated September 13, 1994, at the later of the times specified in paragraph (d)(1) or (d)(2), as applicable, and paragraph (d)(3) of this AD. Repeat the inspection thereafter at intervals not to exceed 6,000 landings or 12,600 flight hours, whichever occurs first. Accomplishment of this inspection terminates the requirements of paragraph (b) of this AD.

(1) For airplanes on which HFEC inspections have not been accomplished in accordance with AD 93-23-07: Prior to the accumulation of 13,200 landings or 27,720 flight hours, whichever occurs first, after accomplishing the modification.

(2) For airplanes on which HFEC inspections have been accomplished in accordance with AD 93-23-07: Within 6,000 landings or 12,600 flight hours, whichever occurs first, after accomplishment of the last inspection performed in accordance with the requirements of paragraph (b) of this AD.

(3) Within 500 landings after the effective date of this AD.

(e) If any crack is found in the center spar sealing angles, including cracking entirely through the sealing angle, during the inspections required by paragraph (a), (b), (c), or (d) of this AD: Prior to further flight, replace the pair of sealing angles on the affected wing and cold work the attachment holes, in accordance with Airbus Repair Drawing R571-40589 or R571-40942; and perform the repetitive inspections required by paragraph (c) or (d) of this AD, as applicable.

(f) If any sealing angle is found to be cracked through entirely during the inspections required by paragraph (a), (b), (c), or (d) of this AD: Prior to further flight, perform additional inspections to detect cracks in the adjacent butt strap and skin panel, in accordance with paragraph 2.B.(5) of Airbus Industrie Service Bulletin A300-57-6027, Revision 2, dated September 13, 1994. If any crack is found in the adjacent buttstrap and skin panel, prior to further flight, repair in accordance with Airbus Repair Drawing R571-40611.

(g) (1) 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.

(g) (2) Operators may request an extension of the compliance times of this AD in accordance with the "adjustment for range" formula found in paragraph 1(d) of Airbus Industrie Service Bulletin A300-57-6027, Revision 2, dated September 13, 1994. The average flight time per flight cycle in hours used in this formula should be for an individual airplane. Average flight time for a group of airplanes may be used if all airplanes in the group have flight times differing by no more than 10 percent. If compliance times are based on the average flight time for a group of airplanes, the individual airplane flight times of the group must be submitted to the Manager, International Branch, ANM-116, for review.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

(h) 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.

(i) The inspections shall be done in accordance with Airbus Industrie Service Bulletin No. A300-57-6027, dated October 8, 1991; and Airbus Industrie Service Bulletin A300-57-6027, Revision 2, dated September 13, 1994. Revision 2 of Airbus Industrie Service Bulletin A300-57-6027 contains the following list of effective pages:Page Number
REVISION LEVEL
Shown on Page

Date Shown on Page
1-7
2
September 13, 1994
8-12
1
November 24, 1993

The incorporation by reference of Airbus Industrie Service Bulletin A300-57-6027, Revision 2, dated September 13, 1994, was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. The incorporation by reference of Airbus Industrie Service Bulletin No. A300-57-6027, including Appendix 1, dated October 8, 1991, was approved previously by the Director of the Federal Register as of January 5, 1994 (58 FR 64112, December 6, 1993). 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 4: The subject of this AD is addressed in French airworthiness directive 91-253-128(B)R1, dated March 1, 1995.

(j) This amendment becomes effective on October 1, 1998.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 93-23-07, amendment 39-8741 (58 FR 64112, December 6, 1993), which is applicable to all Airbus Industrie Model A300-600 series airplanes, was published in the Federal Register on June 18, 1997 (62 FR 33040). The action proposed to supersede AD 93-23-07 to continue to require inspections to detect cracks in the center spar sealing angles adjacent to the pylon rear attachment and in the adjacent butt strap and skin panel, and correction of any discrepancies. The action proposed to require that the initial inspections be accomplished at reduced thresholds, and proposed to limit the applicability of the existing AD.

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

Request to Adopt "Adjustment for Range" Compliance Times
One commenter,the manufacturer, requests that the proposed AD be revised to utilize the "adjustment for range" concept for required compliance thresholds as recommended by Airbus Industrie. The commenter states that, in comparison to the compliance times specified in the related French airworthiness directive, the compliance thresholds specified for paragraphs (c) and (d) of the proposed AD would significantly reduce compliance time for U.S. operators. The commenter considers this difference in the planned compliance intervals to be a change in the FAA s policy regarding inspections, which is not linked to the need to address the unsafe condition, since no technical reason is provided for the difference. Such a deviation is a departure from previously stated FAA policy, which mentions a preference for identical compliance times between the FAA and other airworthiness authorities such as the Direction G n rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France. The commenter further states that the proposed AD, if adopted, would unduly penalize U.S. operators of affected Airbus Industrie Model A300-600 series airplanes.

The FAA does not concur. As stated in the preamble of the proposed AD, utilization of "adjustment for range" calculations may present difficulties in determining if the applicable actions have been accomplished within the appropriate compliance time. While such adjustable compliance times are utilized as part of the Maintenance Review Board program, they do not fit practically into the AD tracking process for operators or for Principal Maintenance Inspectors attempting to ascertain compliance with AD s. Based on reviews of the "adjustment for range" calculations with the FAA Aircraft Evaluation Group, and in further consultation with the manufacturer, the FAA has determined that fixed compliance times should continue to be specified for accomplishment of the actions required by this AD. However, operators may request an extension of the compliance times of this AD in accordance with the "adjustment for range" formula, under the provisions of paragraph (g)(2) of the final rule.

Additionally, the FAA acknowledges that a conservative estimate of the average flight time per flight cycle (landing) was used in development of the compliance times for the actions required by paragraphs (c) and (d) of the AD. Therefore, after additional review of the average flight utilization of the U.S. fleet, the FAA has determined that the fixed compliance thresholds may be extended somewhat, and that these compliance thresholds also should be specified in flight hours, as well as flight cycles. Accordingly, paragraphs (c) and (d) of the final rule have been revised to increase the compliance threshold specified in flight cycles, and to add a compliance threshold specified in flight hours. The extension of the flight cycle threshold is expected to provide additional flexibility for operators in planning for accomplishment of the required actions of this AD, and the addition of flight hours will not be restrictive to any U.S. operator. The cost impact information and NOTE 2 of the AD also have been revised to reflect these changes to the compliance thresholds and intervals of the final rule.

Request to Increase Grace Period
One commenter requests that the grace period for accomplishment of the actions required by paragraph (c) of the proposed AD be increased from 500 to 1,000 flight cycles. This commenter states that the rule, as proposed, lowers the inspection threshold to 4,638 total flight cycles. Because its fleet of affected airplanes has already passed this threshold, the required actions would need to be accomplished within 500 flight cycles after the effective date of the AD, and those actions cannot be accomplished in this timeframe at a line station. However, an increase in the grace period to 1,000 flight cycles would allow this operator to accomplish the required actions at a main maintenance base.

The FAA does not concur with the request to extend the grace period. As discussed previously, the FAA has determined that the compliance threshold and intervals may be extended for accomplishment of the actions required by paragraphs (c) and (d) of this AD. The initial compliance threshold required by paragraph (c) has been revised from 4,638 total flight cycles to require accomplishment of the required actions "Prior to accumulation of 10,600 total flight cycles or 22,600 total flight hours, whichever occurs first." With this extension of the compliance threshold, the FAA considers that operators will have adequate time to accomplish the required actions, and has determined that no further changes to the compliance times of the AD are necessary.

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

Cost Impact
There are approximately 34 Model A300-600 series airplanes of U.S. registry that will be affected by this AD.

The requirements of this AD will not add any new additional economic burden on affected operators, other than the costs that are associated with the initial inspection being required earlier than would have been required by AD 93-23-07 (inspection is now required within 10,600 total landings or 22,260 total flight hours, rather than 12,000 total landings, for certain airplanes; and within 13,200 total landings or 27,720 total flight hours, rather than 15,000 total landings, for certain other airplanes). The current costs associated with AD 93-23-07 are reiterated in their entirety (as follows) for the convenience of affected operators.

The costs associated with the currently required inspections entail 8 work hoursper airplane, per inspection, at an average labor rate of $60 per work hour. (This figure does not include the time necessary for gaining access and closing up.) Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $16,320, or $480 per airplane, per inspection cycle.

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 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 removing amendment 39-8741 (58 FR 64112, December 6, 1993), and by adding a new airworthiness directive (AD), amendment 39-10718, to read as follows: