Airworthiness Directives; Airbus Model A300, A300-600, and A310 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A300, A300-600, and A310 series airplanes, that requires replacement of the transformer rectifier units (TRU) in the avionics compartment with new, improved TRU's. 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 failure of the TRU's. Failure of multiple TRU's could result in loss of the thrust reversers, autothrottle, flaps, and various systems (wing/cockpit window anti-ice, trim tank pumps, and windshield wipers) on the airplane; or incorrect information displayed to the flight crew.

DATES:

Effective October 13, 2000.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of October 13, 2000.

ADDRESSES:

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.

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:

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 A300, A300-600, and A310 series airplanes was published in the Federal Register on April 19, 2000 (65 FR 20922). That action proposed to require replacement of the transformer rectifier units (TRU) in the avionics compartment with new, improved TRU's.

Later Service Bulletin Revisions

Airbus has issued Service Bulletins A300-24-0089, A300-24-6068, and A310-24-2077, all Revision 01, all dated February 10, 2000. The original releases of these service bulletins were cited in the proposed AD as the appropriate source of service information for the actions required by the AD. These later revisions of the service bulletins are essentially equivalent to the previous revisions; however, the interchangeability code has been updated. The AD has been revised to reference the later service bulletin revisions as the appropriate source of service information. A NOTE also has been added to give credit to operators that may have accomplished the actions required by this AD in accordance with the original version of the service bulletins.

Comments Received

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Request To Extend Compliance Time

Three commenters request that the compliance time specified in the proposed AD for the TRU replacements be extended to September 30, 2001, which is the time mandated by the related French airworthiness directive 1999-435-296(B), dated November 3, 1999. One commenter, the TRU vendor, states that the last batch of parts will not be available until December 2000, and the subsequent lead time for modification of the TRU's is 6 to 8 months. Another commenter states that more than 50 percent of TRU's installed on U.S.-registered airplanes are at earlier amendment levels, and these TRU's will require significantly more parts and work hours to accomplish the additional modifications necessary to bring the TRU's to later amendment levels.

Another commenter, the airplane manufacturer, states that there has been no overall decrease in TRU reliability for most operators, and there has been no recent increase in double TRU failures. However, a limited number of operators have experienced a lower mean-time-between-failure (MTBF) rate for the TRU over the last several years. Therefore, the commenter advises that the Master Minimum Equipment List (MMEL) is being revised, to reduce the amount of time in which dispatch is allowed with one TRU inoperative. With the MMEL restriction in place as an interim measure, and given the lack of availability of parts, the commenter proposes extension of the compliance threshold to September 30, 2001.

The FAA partially concurs. The FAA has verified that the lead time for modifying the TRU's will exceed the proposed compliance time of 6 months after the effective date of this AD. In light of this situation, and in consideration of the more restrictive MMEL requirements, the FAA has determined that extending the compliance time as suggested will accommodate the time necessary for affected operators to replace the TRU's, without adversely affecting safety. However, there is no direct analytical relationship identified between the suggested calendar date of September 30, 2001, and the amount of time necessary to accomplish the required actions. Therefore, rather than specifying a calendar date, the FAA has revised the compliance time to 12 months after the effective date of this AD. This threshold should provide operators with time in which to accomplish the requirements of the AD approximately equivalent to the suggested calendar date.

Request To Revise Cost Information

One commenter states that, although the proposed AD provides an estimate of 2 work hours per airplane to accomplish the TRU replacements, about 12 to 16 work hours will actually be required to modify each TRU prior to installation on the airplane. The commenter's work hour estimate includes the time necessary to revise the TRU to later amendment levels (if not already included), prior to modifying the TRU for installation as required by this AD. The commenter also notes that the AD should clarify that the costs of modification to later amendment levels will be borne by the operators. Additionally, the commenter states that only the modification parts provided by the manufacturer will be at no cost to the operators if modification of the TRU's is accomplished at the vendor's (AUXILEC) facilities.

The FAA's intent with regard to the work hour estimate was to provide an approximation of the time required for replacement of all TRU's on an airplane. The estimate was not intended to include all work hours necessary for prior modification of certain TRU's to the required configuration. However, the FAA does not object to noting that additional work hours may be required for accomplishment of such modifications. The cost impact information, below, has been revised accordingly. Additionally, the statement regarding cost of modification parts has been revised to clarify that the statement applies only to modification parts provided by the manufacturer.

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 122 airplanes of U.S. registry will be affected by this AD, that it will take approximately 2 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Additional work hours may be necessary for prior modification of the TRU's. Required parts from the manufacturer will be provided by the manufacturer at no cost to the operators if modification of the TRU's is accomplished at the vendor's (AUXILEC) facilities; otherwise the required parts will cost approximately $253 per TRU. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be between $120 and $1,132 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 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.

2. Section 39.13 is amended by adding the following new airworthiness directive:

2000-18-07 Airbus Industrie: Amendment 39-11892. Docket 2000-NM-54-AD.

Applicability: Model A300, A300-600, and A310 series airplanes; certificated in any category; equipped with AUXILEC transformer rectifier units (TRU) having part number (P/N) F11QB3121.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been 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 failure of multiple TRU's, which could result in loss of the thrust reversers, autothrottle, flaps, and various systems (wing/cockpit window anti-ice, trim tank pumps, and windshield wipers) on the airplane; or incorrect information displayed to the flight crew; accomplish the following:

Replacement

(a) Within 12 months after the effective date of this AD, replace the TRU's in the avionics compartment with new, improved TRU's, in accordance with Airbus Service Bulletin A300-24-0089 (for Model A300 series airplanes), A300-24-6068 (for Model A300-600 series airplanes), or A310-24-2077 (for Model A310 series airplanes); all Revision 01, all dated February 10, 2000; as applicable.

Note 2:

Accomplishment of TRU replacements prior to the effective date of this AD in accordance with Airbus Service Bulletin A300-24-0089, dated March 4, 1998; A300-24-6068, dated January 28, 1998; or A310-24-2077, dated January 21, 1998; as applicable; is acceptable for compliance with paragraph (a) of this AD.

Note 3:

The Airbus service bulletins reference AUXILEC Service Bulletin F11QB3121-24-007, dated February 2, 1998, as an additional source of service information for accomplishing the replacement required by 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 4:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Manager, 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

A300-24-0089, Revision 01, dated February 10, 2000; Airbus Service Bulletin A300-24-6068, Revision 01, dated February 10, 2000; or Airbus Service Bulletin A310-24-2077, Revision 01, dated February 10, 2000; 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 5:

The subject of this AD is addressed in French airworthiness directive 1999-435-296(B), dated November 3, 1999.

(e) This amendment becomes effective on October 13, 2000.