AD 99-27-10

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A310 and A300-600 series airplanes, that requires wiring modifications to the engine and auxiliary power unit (APU) fire detection system. 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 the fire warning from terminating prematurely, which could result in an unnoticed, uncontained engine/APU fire.

Final rule.

99-27-10 AIRBUS INDUSTRIE: Amendment 39-11491. Docket 99-NM-222-AD. Issued December 23, 1999.
Applicability: Model A310 and A300-600 series airplanes, certificated in any category; except those on which Airbus Modifications 06267 and 07340 have been accomplished during production.

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 the fire warning from terminating prematurely, which could result in an unnoticed, uncontained engine/auxiliary power unit (APU) fire, accomplish the following:

Modifications
(a) Within 24 months after the effective date of this AD, accomplish the wiring modifications to the engine and APU fire detection system in the relay box 282VU and the electronics rack 90VU in accordance with Airbus Service Bulletin A310-26-2024, Revision 04, dated March 5, 1999 (for Model A310 series airplanes); or A300-26-6038, dated March 5, 1999, or Revision 1, dated September 8, 1999 (for Model A300-600 series airplanes); as applicable.

Alternative Methods of Compliance
(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 theManager, 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.

Special Flight Permits
(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.

Incorporation by Reference
(d) The modifications shall be done in accordance with Airbus Service Bulletin A310-26-2024, Revision 04, dated March 5, 1999; Airbus Service Bulletin A300-26-6038, dated March 5, 1999; or Airbus Service Bulletin A300-26-6038, Revision 1, dated September 8, 1999; as applicable. 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 1999-238-286(B), dated June 2, 1999.
e. This amendment becomes effective on February 8, 2000.

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 A310 and A300-600 series airplanes was published in the Federal Register on October 6, 1999 (64 FR 54248). That action proposed to require wiring modifications to the engine and auxiliary power unit (APU) fire detection system.

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 supports the proposed AD.

Request to Change Material in the Electrical Cabling
One commenter provides data that suggest that the FAA should require an alternative material for the electrical cabling to the engine s core wiring harnesses for the engine/APU fire detection system, rather than require a change to the control logicof the fire detection system. The commenter states that the presently used wire harness will degrade rapidly in the high temperature and vibration environment. The commenter describes an alternative material that can withstand these severe environments without degradation. Thus, it could prevent damage to the wire harness in the event of an engine fire.

The FAA does not concur with the proposal. The Airbus service bulletins referenced as the appropriate sources of service information for accomplishment of the wiring modifications required by this AD address the potential for the APU engine fire warning to terminate prematurely; these service bulletins provide a design change to the detection system control logic that would address the identified unsafe condition. The FAA has determined that the installation of electrical cabling made of an alternative material, though increasing the harness resistance, wound not ensure a reliable fire detection system control logic. Although a change in the cabling material may provide some long-term benefit, it does not directly correct the unsafe condition identified and addressed in this AD. No change to the AD is required.

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 113 airplanes of U.S. registry will be affected by this AD, that it will take approximately 5 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $408 per airplane. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $80,004, or $708 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 thatno operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact
The regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132.

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: