Airworthiness Directives; Airbus Model 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 A300-600 series airplanes. This proposal would require modification of certain electrical looms of the nose and main landing gear and modification of the rotor shaft attachment of the nose and main landing gear tachometers. 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 erratic operation of the wheel tachometers, which could result in degradation of the braking performance, and possible increased landing roll.

EFFECTIVE DATE:

Comments must be received by March 27, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-362-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 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, FAA, 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 99-NM-362-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. 99-NM-362-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 A300-600 series airplanes. The DGAC advises that it has received a report indicating that, after touchdown, an airplane overran the runway due to degradation of the braking system performance combined with non-extension of spoilers 1 and 4. Investigation into the degradation of the braking system performance and the non-extension of the spoilers revealed that the cause was attributed to incorrect speed signals supplied by the wheel tachometers due to:

• Moisture, dirt, and subsequent corrosion of the electrical connectors of the nose and main landing gears; and
• Fracture of the coupling pins between the rotor shaft attachment and the drive coupling of the tachometer.

These conditions, if not corrected, could result in erratic operation of the tachometers, which could cause a significant degradation of the braking system performance. Furthermore, if a tachometer on an aft wheel of the main landing gear is not operating correctly, this condition could affect the control logic of the spoiler extension and could result in an increased landing roll.

Explanation of Relevant Service Information

The manufacturer has issued Airbus Service Bulletin A300-32-6069, Revision 01, dated December 29, 1999, which describes procedures for modification of certain electrical looms of the nose and main landing gears. The modification involves installing heat-shrinkable sheaths on the ground/flight detection loom connectors and strut-locking switches, and draining the looms of certain locking switches.

The manufacturer also has issued Airbus Service Bulletin A300-32-6077, Revision 01, dated September 25, 1999, which describes procedures for modification of the rotor shaft attachment of the nose and main landing gear tachometers. This modification involves machining the rotor assembly and either machining or replacing the drive coupling with a new drive coupling, and attaching the rotor shaft to the drive coupling with a rivet.

Accomplishment of the actions specified in the Airbus service bulletins is intended to adequately address the identified unsafe condition. The DGAC classified these service bulletins as mandatory and issued French airworthiness directive 1999-428-295(B), dated November 3, 1999, in order to assure the continued airworthiness of these airplanes in France.

The Airbus service bulletins reference Messier-Dowty Service Bulletin 470-32-779, dated April 14, 1997; Messier-Dowty Service Bulletin 470-32-777, dated July 1, 1997; and Messier-Bugatti Service Bulletin C20105-32-782, dated October 17, 1996, as additional sources of service information for accomplishing the requirements of this proposed AD.

FAA's Conclusions

This airplane model is manufactured in France and is type certificated for operation in the United States under the provisions of section 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 accomplishment of the actions specified in the Airbus service bulletins described previously.

Cost Impact

The FAA estimates that 79 airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 7 work hours per airplane to accomplish the proposed modification of the electrical looms, at an average labor rate of $60 per work hour. Required parts would cost approximately $687 per airplane. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $87.453, or $1,107 per airplane.

It would take approximately 13 work hours per airplane to accomplish the proposed modification of the rotor shaft attachment, at an average labor rate of $60 per work hour. Required parts would cost approximately $169 per airplane. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $74,971, or $949 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.