AD 99-06-09

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A320 series airplanes, that requires an electrical continuity test of the discharge circuit for the cargo compartment fire extinguisher bottle to detect any cross-connection of the electrical wires in the cargo compartment discharge circuit, and corrective actions, if necessary. 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 prevent incorrect distribution of fire extinguishing chemicals in the event of a fire in the cargo compartment, which, if unconfined, could spread beyond the cargo compartment.

Final rule.

99-06-09 AIRBUS INDUSTRIE: Amendment 39-11073. Docket 98-NM-105-AD.

Applicability: Model A320 series airplanes having manufacturer serial numbers 002 through 402 inclusive, on which Airbus Modification 20071 (reference Airbus Service Bulletin A320-26-1020, Revision 1, dated January 4, 1993) has been accomplished; except those airplanes on which Airbus Service Bulletin A320-26-1034, dated May 9, 1995; Revision 1, dated September 13, 1995; Revision 2, dated April 1, 1996; or Revision 3, dated December 5, 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 (b) 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 incorrect distribution of fire extinguishing chemicals in the event of a fire in the cargo compartment, which, if unconfined, could spread beyond the cargo compartment, accomplish the following:

(a) Within 450 flight hours after the effective date of this AD, perform a one-time electrical continuity test of the discharge circuit for the cargo compartment fire extinguisher bottle to detect any cross-connection of the electrical wires in the cargo compartment discharge circuit, in accordance with Airbus All Operator Telex (AOT) A320/AOT 26-10, dated April 5, 1993. If any anomaly is detected, prior to further flight, accomplish corrective actions in accordance with the AOT.

(b) 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.

(c) 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.

(d) The actions shall be done in accordance with Airbus AllOperator Telex A320/AOT 26-10, dated April 5, 1993. 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 94-056-051(B), dated March 16, 1994.

(e) This amendment becomes effective on April 16, 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 A320 series airplanes was published in the Federal Register on May 20, 1998 (63 FR 27687). That action proposed to require an electrical continuity test of the discharge circuit for the cargo compartment fire extinguisher bottle to detect any cross-connection of the electrical wires in the cargo compartment discharge circuit, and corrective actions, if necessary.

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.

Support for the Proposal
One commenter, the manufacturer, supports the proposal.

Request to Exclude Certain Airplanes from the Applicability
One commenter requests that the applicability of the proposed AD be revised to exclude airplanes on which the actions specified in Airbus Service Bulletin A320-26-1034 have been accomplished. The commenter states that accomplishment of this service bulletin will prevent inadvertent cross-connection of the fire extinguisher wiring.

The FAA concurs. The FAA has reviewed Airbus Service Bulletin A320-26-1034, dated May 9, 1995; Revision 1, dated September 13, 1995; Revision 2, dated April 1, 1996; and Revision 3, dated December 5, 1997. This service bulletin and its revisions describe procedures for modification of the wiring routing to connectors to the fire extinguisher bottle of the cargo compartment. The FAA finds that accomplishment of this modification also adequately addresses the identified unsafe condition. Therefore, the FAA finds that airplanes on which the modification specified in Airbus Service Bulletin A320-26-1034 has been accomplished are not subject to the requirements of this AD. The FAA has revised the applicability of the final rule accordingly.

Request to Include Certain Airplanes in the Applicability
One commenter requests that the applicability of the proposed AD be revised to include airplanes on which the modification specified in Airbus Service Bulletin A320-26-1051 (which describes procedures for the installation of a fire extinguishing system in the forward cargo compartment) has been accomplished. The commenter asserts that Airbus Service Bulletin A320-26-1051 accomplishes the same technical intent as Airbus Service Bulletin A320-26-1020 (which specifies such installation in both the forward and aft cargo compartments). The commenter concludes that airplanes on which Service Bulletin A320-26-1051 has been accomplished also should be subject to the requirements of the proposed AD.

The FAA does not concur. If operators elect to accomplish optional Airbus Service Bulletin A320-26-1051, that service bulletin specifies accomplishment of Airbus Service Bulletin A320-26-1034. Because the actions specified by Service Bulletin A320-26-1034are to be accomplished prior to or concurrently with those specified by Service Bulletin A320-26-1051, it will not be necessary to include in the final rule airplanes on which Service Bulletin A320-26-1051 has been accomplished. As discussed above, airplanes on which the modification specified in Airbus Service Bulletin A320-26-1034 has been accomplished are not subject to the requirements 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 change described previously. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact
The FAA estimates that 118 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour 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 $7,080, or $60 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.

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: