AD 98-18-24

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A320 series airplanes, that requires repetitive inspections to detect cracking in the inner flange of door frame 66, and corrective actions, if necessary. This amendment also provides for an optional terminating action for 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 correct fatigue cracking in the inner flange of door frame 66, which could result in reduced structural integrity of the airplane.

Final rule.

98-18-24 AIRBUS INDUSTRIE: Amendment 39-10740. Docket 97-NM-156-AD.

Applicability: Model A320 series airplanes on which Airbus Modification 21778 (reference Airbus Service Bulletin A320-53-1072, dated November 7, 1995, as revised by Change Notice 0A, dated July 5, 1996) has not 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 (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 notbeen eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To correct fatigue cracking in the inner flange of door frame 66, left and right, which could result in reduced structural integrity of the airplane, accomplish the following:

(a) Prior to the accumulation of 20,000 total flight cycles, or within 1 year after the effective date of this AD, whichever occurs later: Perform a rotating probe eddy current inspection to detect cracking around the edges of the gusset plate attachment holes of the inner flange of door frame 66, left and right, at stringer positions P18, P20, P22, P18', P20', and P22', in accordance with Airbus Service Bulletin A320-53-1071, dated November 7, 1995, as revised by Change Notice 0A, dated July 5, 1996. If any crack is detected, prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate. Repeat the inspection thereafter at intervals not to exceed 20,000 flight cycles.

(b) Modification of the gusset plate attachment holes of the inner flange of door frame 66, left and right (Airbus Modification 21778), in accordance with Airbus Service Bulletin A320-53-1072, dated November 7, 1995, as revised by Change Notice 0A, dated July 5, 1996, constitutes terminating action for the repetitive inspection requirements of this AD.

(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 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.

(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.

(e) The inspections shall be done in accordance with Airbus Service Bulletin A320-53-1071, dated November 7, 1995, as revised by Change Notice 0A, dated July 5, 1996. 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 96-234- 087(B),dated October 23, 1996.

(f) This amendment becomes effective on October 20, 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 A320 series airplanes was published in the Federal Register on May 12, 1998 (63 FR 26102). That action proposed to require repetitive inspections to detect cracking in the inner flange of door frame 66, and corrective actions, if necessary. That action also proposed to provide for an optional terminating action for the repetitive inspections.

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

One commenter supports the intent of the proposed rule.

Request to Allow Flight with Known Cracks
One commenter, the manufacturer, requests that the proposed AD be revised to allow operators to continue operation of an unrepaired airplane following detection of cracks, utilizing thefollow-on inspections and conditions described in Airbus Service Bulletin A320-53-1071. The commenter states that the follow-on inspection intervals are based on fatigue test results and calculations of the crack propagation rate, depending on the crack length. The commenter also states that the structure of the Airbus Model A320 series airplane is classified as damage tolerant. Additionally, the commenter notes that the inspection program specified in the service bulletin was developed in order to prevent the need for extensive repairs of the airplane.

The FAA does not concur. It is the FAA s policy to require repair of known cracks prior to further flight, except in certain cases of unusual need, as discussed below. This policy is based on the fact that such damaged airplanes do not conform to the FAA certificated type design, and therefore, are not airworthy until a properly approved repair is incorporated. While recognizing that repair deferrals may be necessary at times,the FAA policy is intended to minimize adverse human factors relating to the lack of reliability of long-term repetitive inspections, which may reduce the safety of the type certificated design if such repair deferrals are practiced routinely.

As noted above, the FAA s policy regarding flight with known cracks does allow deferral of repairs in certain cases, if there is an unusual need for a temporary deferral. Unusual needs include such circumstances as legitimate difficulty in acquiring parts to accomplish repairs. Under such conditions, the FAA may allow a temporary deferral of the repair, subject to a stringent inspection program acceptable to the FAA. The FAA acknowledges that the manufacturer has specified inspection intervals that are intended to allow continued operation with known cracks, and to prevent the need for extensive repairs. However, since the FAA is not aware of any unusual need for repair deferral in regard to this AD, the FAA has not evaluated these inspection intervals.

Additionally, the FAA policy applies to airplanes certificated to damage tolerance evaluation regulations as well as those not so certificated. Therefore, the commenter's statement that "the Airbus Model A320 airplane structure is classified as damage tolerant" is not relevant to the application of the FAA s policy in this regard.

The FAA considers the compliance times in this AD to be adequate to allow operators to acquire parts to have on hand in the event that a crack is detected during inspection. Therefore, the FAA has determined that, due to the safety implications and consequences associated with such cracking, any subject area that is found to be cracked must be repaired or modified prior to further flight. No change to the final rule is 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 as proposed.Cost Impact
The FAA estimates that 132 Airbus Model A320 series airplanes of U.S. registry will be affected by this AD, that it will take approximately 8 work hours per airplane to accomplish the required inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $63,360, or $480 per airplane.

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 modification, it would take approximately 5 work hours per airplane to accomplish the actions, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the optional modification provided by this AD on U.S. operators is estimated to be $300 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: