AD 99-20-05 ACTIVE

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A319, A320, and A321 series airplanes, that requires modification of the 90VU electronics rack umbrellas, the 91VU upper shelf assembly, the cockpit drain circuit, and the electrical wire routing above the 90VU electronics rack. 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 damage to computer electrical connectors due to ingress of water into the avionics bay, which could result in malfunctioning of the avionics computers.

Final rule.

99-20-05 AIRBUS INDUSTRIE: Amendment 39-11335. Docket 98-NM-270-AD.

Applicability: Model A319, A320, and A321 series airplanes, certificated in any category, on which Airbus Modification 25995 has not been accomplished.

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 damage to computer electrical connectors due to ingress of water into the avionics bay, which could result in malfunctioning of the avionics computers, accomplish the following:

Modification
(a) Within 30 months after the effective date of this AD, modify the 90VU electronics rack umbrellas, the 91VU upper shelf assembly, the cockpit drain circuit, and the electrical wire routing above the 90VU electronics rack; in accordance with Airbus Service Bulletin A320-25-1186, Revision 02, dated April 27, 1999.

NOTE 2: Accomplishment of the modification required by paragraph (a) of this AD in accordance with Airbus Service Bulletin A320-25-1186, dated December 1, 1997, or Revision 01, dated September 23, 1998, prior to the effective date of this AD, is considered acceptable for compliance with the requirements of this AD.

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 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.

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 actions shall be done in accordance with Airbus Service Bulletin A320-25-1186, Revision 02, dated April 27, 1999. 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 98-178-115(B), dated May 6, 1998.

(e) This amendment becomes effective on October 29, 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 A319, A320, and A321 series airplanes was published in the Federal Register on June 2, 1999 (64 FR 29607). That action proposed to require modification of the 90VU electronics rack umbrellas, the 91VU upper shelf assembly, the cockpit drain circuit, and the electrical wire routing above the 90VU electronics rack.

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.

One commenter supports the proposal. Another commenter states that it has no objection to the requirements of the proposed rule or the compliance period.

Later Revision of Service Bulletin
One commenter, an operator, states that it plans to accomplish removal of shelves to improve access to the areain accordance with Airbus Service Bulletin A320-25-1186, Revision 02, dated April 27, 1999. Revision 01 of this service bulletin, dated September 23, 1998, was cited in the proposed AD as the appropriate source of service information. The FAA has reviewed Revision 02 of the service bulletin and has determined that it is essentially the same as the previous revision except in allowing for removal of certain shelves to allow easier access to the area. The FAA has revised paragraph (a) of the AD to require accomplishment of the modification in accordance with Revision 02 of the service bulletin, and has revised NOTE 2 to give credit to operators who may have previously accomplished the modification in accordance with Revision 01.

Request to Revise Compliance Time
One commenter, an operator, requests that the compliance time for modification of the moisture shroud (umbrella) in accordance with Airbus Service Bulletin A320-25-1186, which is "two years after the effective date of this AD," be revised to have the same compliance deadline as that specified in FAA AD 99-02-03, amendment 39-10992 (64 FR 2552, January 15, 1999). Accomplishment of A320-24-1054 is required by AD 99-02-03 within three years after the effective date of that AD, resulting in a compliance date of February 19, 2002. The commenter notes that it is necessary to install the moisture shroud as described in Airbus Service Bulletin A320-24-1054, on airplanes delivered without the shroud, prior to accomplishing the modification of the shroud described in A320-25-1186.

The FAA concurs. The FAA has determined that the compliance time in this AD for modification of the moisture shroud as described in Airbus Service Bulletin A320-25-1186, Revision 02, dated April 27, 1999, should be revised to allow for prior or concurrent accomplishment of the actions specified in Airbus Service Bulletin A320-24-1054, Revision 02, dated September 22, 1993. The FAA has extended the compliance time for modification of the shroud as required by this AD by 6 months, which will provide operators with adequate time to schedule and accomplish the requirements of AD 99-02-03 prior to or concurrent with the requirements of this AD. The FAA has determined that such an extension will have no adverse effect on safety. Paragraph (a) of this AD has been revised to specify the extended compliance time of 30 months.

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 140 airplanes of U.S. registry will be affected by this AD, that it will take approximately 19 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 perwork hour. Required parts will be supplied by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $159,600, or $1,140 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:

The service information referenced in this AD may be obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Norman B. Martenson, Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2110; fax (425) 227-1149.