Airworthiness Directives; Airbus Model A300 and A300-600 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Airbus Model A300 and A300-600 series airplanes. This proposal would require repetitive inspections to detect chafing and the existence of repairs of the harness of the high-level sensor of the fuel surge tanks, and to detect chafe marks on the support canisters of the magnetic level indicators; and follow-on corrective actions, if necessary. This proposal also would require modification of the harness for the high-level sensor of the outer wing fuel tanks, which would terminate certain repetitive inspections. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent chafing of the harness of the high-level sensor, which could result in a short circuit and consequent fuel ignition source inside the outer wing fuel tanks.

DATES:

Comments must be received by July 13, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-96-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule may be obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

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

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-96-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-96-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition may exist on certain Airbus Model A300 and A300-600 series airplanes. The DGAC advises that maintenance personnel found a chafed harness (cable) in the outer wing fuel tank. The harness is routed to the surge tank high-level sensor. Investigation revealed that clipping and routing of the cable (wiring) coupled with excessive slack of the cable between the “P” clips allows the cable to chafe against the support canister for the magnetic level indicator. Such chafing, if not corrected, could result in a short circuit and consequent fuel ignition source inside the outer wing fuel tank.

Explanation of Relevant Service Information

The manufacturer has issued Airbus Service Bulletins A300-28-0077 (for Model A300 series airplanes), and A300-28-6062 (for Model A300-600 series airplanes), each dated July 19, 1999. These service bulletins describe procedures for repetitive inspections to detect chafing and the existence of repairs of the harness of the high-level sensor of the fuel surge tanks, and to detect chafe marks on the support canisters of the magnetic level indicators; and follow-on corrective actions, if necessary. The follow-on corrective actions involve removing original repairs, if necessary, and accomplishing a splice repair and installing sleeves to the inner and outer cable coverings. The service bulletins categorize the repairs as either temporary or permanent depending upon the location of the repair and whether certain previous repairs were accomplished. In addition, the follow-on corrective actions include a repetitive visual inspection of the harness to ensure the integrity of the repair. This inspection would be performed if certain conditions (e.g., any temporary repairs) exist.

The manufacturer also has issued Airbus Service Bulletins A300-28-0058, Revision 02 (for Model A300 series airplanes), and A300-28-6020, Revision 01 (for Model A300-600 series airplanes), each dated September 28, 1999. These service bulletins describe procedures for modification of the harness for the high-level sensor in the outer wing fuel tanks. The modification involves re-routing the cables and installing longer cleats and reversing the “P” clips that support the cables. This modification will prevent the cables from sagging and ensure adequate clearance between the cables and the support canisters of the magnetic level indicators. Accomplishment of the modification eliminates the need for certain repetitive inspections of the harness of the high-level sensor of the fuel surge tanks. However, the modification does not eliminate the need for the 10,000-flight-hour detailed visual inspections specified in the follow-on corrective actions, following the accomplishment of any temporary repairs.

The DGAC classified Airbus Service Bulletins A300-28-0077 and A300-28-6062 as mandatory and issued French airworthiness directive 1999-404-293(B), dated October 6, 1999, in order to assure the continued airworthiness of these airplanes in France.

FAA's Conclusions

These airplane models are manufactured in France and are type certificated for operation in the United States under the provisions of § 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would require repetitive inspections to detect chafing and the existence of repairs of the wire harnesses of the high-level sensors; and to detect chafe marks on the support canisters of the magnetic level indicators; and follow-on corrective actions, if necessary. This proposal also would require modification of the harness for the high-level sensor of the outer wing fuel tanks, which would terminate certain repetitive inspections. The actions would be required to be accomplished in accordance with the service bulletins described previously, except as discussed below.

Difference Between Proposed AD and Related Service Information

Operators should note that this AD proposes to mandate, within 18 months, the modification of the harness of the high-level sensor of the outer wing fuel tanks described in Airbus Service Bulletin A300-28-0058, Revision 02, or A300-28-6020, as terminating action for certain repetitive inspections. [Incorporation of the terminating action is optional in French airworthiness directive 1999-404-293(B).]

The FAA has determined that long-term continued operational safety will be better assured by design changes to remove the source of the problem, rather than by repetitive inspections. Long-term inspections may not provide the degree of safety assurance necessary for the transport airplane fleet. This, coupled with a better understanding of the human factors associated with numerous continual inspections, has led the FAA to consider placing less emphasis on inspections and more emphasis on design improvements. The proposed modification requirement is consistent with these conditions.

Cost Impact

The FAA estimates that 37 series airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 1 work hour per airplane to accomplish the proposed repetitive detailed visual inspections, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $2,220, or $60 per airplane, per inspection cycle.

It would take approximately 1 work hour per airplane to accomplish the proposed modification, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $2,220, or $60 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed 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 proposed herein would 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 proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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.