AD 98-13-23

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A300-600 series airplanes, that requires inspections to detect corrosion and cracking of the lower horizontal stabilizer cutout longeron, the corner fitting, the skin strap, and the outer skin; and repair, if necessary. This amendment is prompted by cracking found at the lower corner of the horizontal stabilizer cutout longeron during a full scale fatigue test. The actions specified by this AD are intended to prevent such cracking, which could result in reduced structural integrity of the horizontal-stabilizer cutout longeron.

Final rule.

98-13-23 AIRBUS INDUSTRIE: Amendment 39-10614. Docket 95-NM-78-AD.

Applicability: Model A300-600 series airplanes on which Airbus Modification No. 6146 has not been installed, 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 use the authority provided in paragraph (f) of this AD to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD.In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent reduced structural integrity of the horizontal stabilizer cutout longeron due to fatigue cracking, accomplish the following:

(a) Prior to the accumulation of 18,000 total landings, or within 2,000 landings after the effective date of this AD, whichever occurs later: Perform a visual and an eddy current inspection to detect cracks and/or corrosion of Areas 1 and 2 of the lower horizontal stabilizer cutout longeron, as defined in Airbus Service Bulletin A300-53-6042, Revision 1, dated February 20, 1995. Perform the inspections in accordance with the service bulletin.

(b) Perform a visual and an eddy current inspection to detect cracks and/or corrosion of Area 3 of the lower horizontal stabilizer cutout longeron, as defined in Airbus Service Bulletin A300-53-6042, Revision 1, dated February 20, 1995. Perform these inspections in accordance with the service bulletin, at the later of the times specified in paragraphs (b)(1) and (b)(2) of this AD.

(1) Prior to the accumulation of 24,000 total landings, but not before the accumulation of 18,000 total landings; or

(2) Prior to the accumulation of 2,000 landings after the effective date of this AD.

(c) If no cracking is detected during any inspection required by this AD: Prior to further flight, cold work and ream the vacated fastener holes, in accordance with Airbus Service Bulletin A300-53-6042, Revision 1, dated February 20, 1995; and perform the requirements of paragraph (c)(1) or (c)(2) of this AD, as applicable.

(1) For airplanes on which no cracking is found in Area 1 or 2: Repeat the inspections required by paragraph (a) of this AD thereafter at intervals not to exceed 6,000 flight cycles.

(2) For airplanes on which no cracking is found in Area 3: Perform the various follow-on actions in accordance with the service bulletin. (The follow-on actions include installing a new corner fitting, installing a new longeron, and performing a cold working procedure.) After accomplishment of these follow-on actions, no further action is required by this AD.

(d) If any cracking is detected during any inspection required by this AD, perform the requirements of paragraph (d)(1) or (d)(2) of this AD, as applicable.

(1) If any cracking is found in Area 1 or 3 that is within the limits specified in Airbus Service Bulletin A300-53-6042, Revision 1, dated February 20, 1995: Prior to further flight, repair in accordance with the service bulletin.

(2) If any cracking is found in Area 2, or if any cracking is found in any area and that cracking is beyond the limits described in Airbus Service Bulletin A300-53-6042, Revision 1, dated February 20, 1995: Prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate.

(e) If any corrosion is detected during any inspection required by this AD, prior to further flight, repair the corrosion in accordance with Airbus Service Bulletin A300-53-6042, Revision 1, dated February 20, 1995.

(f) 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 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Manager, International Branch, ANM-116.

(g) 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.

(h) Except as provided by paragraph (d)(2) of this AD, the actions shall be done in accordance with Airbus Service Bulletin A300-53-6042, Revision 1, dated February 20, 1995. 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 94-269- 171(B)R1, dated March 29, 1995.

(i) This amendment becomes effective on July 30, 1998.

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 A300-600 series airplanes was published in the Federal Register on December 12, 1995 (60 FR 63665). That action proposed to require repetitive visual and eddy current inspections to detect corrosion and fatigue cracking of the lower horizontal stabilizer cutout longeron, the corner fitting, the skin strap, and the skin between FR87 and FR89 and between STGR24 and STGR27, left-hand and right-hand. That action also proposed to require repetitive rotating probe inspections to detect cracks in the fastener holes at the same locations; and repair or certain follow-on actions, if necessary.

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 hasno objection to the proposed rule.

Request to Revise Compliance Time to Permit "Adjustment of Range"
One commenter, the manufacturer, requests that the compliance times for the inspection threshold and the repetitive intervals proposed be revised to follow the recommendations of the Airbus service bulletin specified in the proposed rule. That service bulletin specifies that inspection thresholds and intervals may be adjusted based on certain average flight operations of the airplane. The commenter states that this approach was approved by the Direction G n rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, in its approval of the service bulletin.

The FAA does not concur that the compliance times should be revised. As explained in the proposal, the FAA has determined that such adjustments may not address the unsafe condition in a timely manner. In developing appropriate compliance times for the proposed rule, the FAA considered not only the manufacturer s recommendation, but the safety implications involved with cracking of the horizontal stabilizer cutout longeron and the number of landings that had been accumulated when cracking was detected. Therefore, this AD does not permit such adjustments, and no change to the compliance times of the final rule has been made. However, operators may request approval of an adjustment of the compliance time under the provisions of paragraph (f) of this AD, provided that such adjustment provides an acceptable level of safety.

Remove Touch-and-Go Landings from the Total Number of Landings
This same commenter requests that touch-and-go landings not be included in calculating the total number of airplane landings. The commenter points out that most of the relevant fatigue parameters for touch-and-go flights are less significant than for conditions of normal flight. Further, the commenter states that including touch-and-go s in the total landing count for an individual airplane is tooconservative, considering the high penalty of counting each touch-and-go.

The FAA does not concur. Fatigue cracking has been found at the lower corner of the horizontal stabilizer cutout longeron. Since fatigue cracking in that area is aggravated by landing, the FAA finds that all touch-and-go landings must be counted in determining the total number landings between consecutive inspections.

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 as proposed.

Cost Impact
The FAA estimates that 2 Airbus Model A300-600 series airplanes of U.S. registry will be affected by this AD, that it will take approximately 268 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $32,160, or $16,080 per airplane.

The cost impact figure discussed above is 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 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: