AD 98-20-26

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A320-111, -211, and -231 series airplanes, that requires repetitive inspections to detect missing or cracked bolts and fittings of the frame-to-pressure-floor connection; and corrective actions, if necessary. This amendment also provides for optional terminating action for the repetitive inspections of the affected fittings. 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 detect and correct fatigue cracking in the bolts and fittings of the frame-to-pressure-floor connection, which could result in reduced structural integrity of the airplane.

Final rule.

98-20-26 AIRBUS INDUSTRIE: Amendment 39-10792. Docket 98-NM-20-AD.

Applicability: Model A320-111, -211, and -231 series airplanes; as listed in Airbus Service Bulletin A320-53-1083, Revision 2, dated August 28, 1997; 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 (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 detect and correct fatigue cracking in the bolts and fittings of the frame-to-pressure-floor connection, 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 60 days after the effective date of this AD, whichever occurs later, perform a detailed visual inspection to detect cracked or missing bolts and fittings of the frame-to-pressure-floor connection at frames 43 and 44, in accordance with Airbus Service Bulletin A320-53-1083, Revision 2, dated August 28, 1997. If no crack is detected, repeat the detailed visual inspection thereafter at intervals not to exceed 5,100 flight cycles.

(1) If any bolt is found to be cracked or missing during any inspection required by paragraph (a) of this AD, prior to further flight, replace the bolt with a new bolt in accordance with the service bulletin. Repeatthe detailed visual inspection thereafter at intervals not to exceed 5,100 flight cycles.

(2) If any fitting is found to be cracked during any inspection required by paragraph (a) of this AD, prior to further flight, accomplish the actions specified in paragraph (b) of this AD for the cracked fitting and its corresponding bolts and fuselage frame, in accordance with Airbus Service Bulletin A320-53-1015, Revision 02, dated July 17, 1997.

(b) Reinforcement of the fitting in accordance with Airbus Service Bulletin A320-53-1015, Revision 02, dated July 17, 1997, constitutes terminating action for the requirements of this AD for the affected fitting.

NOTE 2: Reinforcement of the fitting accomplished prior to the effective date of this AD in accordance with Airbus Service Bulletin A320-53-1015, dated December 12, 1995, or Revision 1, dated July 25, 1995, is considered acceptable for compliance with the reinforcement specified in paragraphs (a)(2) and (b) of this AD.

(c) Analternative 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 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.

(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 A320-53-1083, Revision 2, dated August 28, 1997. The reinforcement, if accomplished, shallbe done in accordance with Airbus Service Bulletin A320-53-1015, Revision 02, dated July 17, 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 4: The subject of this AD is addressed in French airworthiness directive 97-316-110(B), dated October 22, 1997.

(f) This amendment becomes effective on October 27, 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 A320-111, -211, and -231 series airplanes was published in the Federal Register on April 14, 1998 (63 FR 18153). That action proposed to require repetitive inspections to detect missing or cracked bolts and fittings of the frame-to-pressure-floor connection; and corrective actions, if necessary. That action also proposed to provide for optional terminating action for the repetitive inspections of the affected fittings.

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 proposed rule.

Request to Allow Flight with Known Cracks
One commenter requests that the FAA allow flight of the airplane with known cracks. The commenter states that the structure of Airbus Model A320 series airplanes is classified as damage tolerant. The commenter also states that it has defined a certain number of flights that allows continued operation with a cracked or broken part, depending on the measured crack length and number of cracked bolts detected.

The FAA does not concur with the commenter s request to allow flight of an airplane with known cracks. It is the FAA s policy to require repair of known cracks prior to further flight, except in certain cases of unusual need (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 s 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 ifsuch repair deferrals are practiced routinely.

Additionally, the FAA s policy applies to airplanes certificated to damage tolerance evaluation regulations as well as those not so certificated. The FAA finds that 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 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, among other things, such circumstances as legitimate difficulty in acquiring parts to accomplish repairs. Under such conditions, the FAA may allow temporary deferral of the repair, subject to a stringent inspection program acceptable to the FAA. However, since the FAA is not aware of any unusual need for repair deferral in regard to this AD, the FAA finds that the compliance times specified in the final rule are adequate to allow operators to acquire parts to have on hand in the event that a crack is detected during an inspection. Therefore, the FAA has determined that, due to safety implications and consequences associated with such cracking, any subject bolt or fitting that is found to be cracked or broken must be repaired or modified prior to further flight. No change to the final rule is necessary.

Request to Reference Earlier Airbus Service Bulletins as Terminating Action
One commenter requests that the proposed AD be revised to reference Airbus Service Bulletin A320-53-1015, dated December 12, 1995, and Revision 1, dated July 25, 1995, as additional sources of service information for accomplishment of the optional terminating action. The FAA concurs. The FAA finds that the procedures specified in the earlier revisions of the subject service bulletin are essentially identical to those specified in Revision 02 of the service bulletin (which was referenced in the NPRM as the appropriatesource of service information for accomplishment of the optional terminating action). Therefore, the FAA has revised the final rule to include a new NOTE to specify that reinforcement of the fitting prior to the effective date of this AD, in accordance with the earlier revisions of the subject service bulletin, is considered acceptable for compliance with the reinforcement specified in paragraphs (a)(2) and (b) of this AD.

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
The FAA estimates that 5 Model A320-111, -211, and -231 series airplanes of U.S. registry will be affected by this AD, that it will take approximately 9 work hours per airplane to accomplishthe 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 $2,700, or $540 per airplane, per inspection 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 action that is provided by this AD action, it would take approximately 119 work hours to accomplish it, at an average labor rate of $60 per work hour. The cost of required parts would be approximately $12,920 per airplane. Based on these figures, the cost impact of the optional terminating action would be $20,060 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 14CFR 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: