Airworthiness Directives; Airbus Model A319, A320, and A321 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Airbus Model A319, A320, and A321 series airplanes, that currently requires repetitive inspections to detect wear of the inboard flap trunnions, and to detect wear or debonding of the protective half-shells; and corrective actions, if necessary. This proposal would require accomplishment of the previously optional terminating action. 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 and resultant wear damage on the inboard flap drive trunnions or on the protective half-shells, which could result in failure of the trunnion primary load path; this would adversely affect the fatigue life of the secondary load path and could lead to loss of the flap.

DATES:

Comments must be received by October 20, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-381-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. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 99-NM-381-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

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.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

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-381-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-381-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On August 10, 1999, the FAA issued AD 99-17-11, amendment 39-11259 (64 FR 45868, August 23, 1999), applicable to certain Airbus Model A319, A320, and A321 series airplanes, to require repetitive inspections to detect wear of the inboard flap trunnions, and to detect wear or debonding of the protective half-shells; and corrective actions, if necessary. That action was prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The requirements of that AD are intended to detect and correct chafing and resultant wear damage on the inboard flap drive trunnions or on the protective half-shells, which could result in failure of the trunnion primary load path; this would adversely affect the fatigue life of the secondary load path and could lead to loss of the flap.

Actions Since Issuance of Previous Rule

AD 99-17-11 provides for an optional modification, which, if accomplished, would constitute terminating action for the required inspections. Since the issuance of that AD, the FAA has determined that the modification should be made mandatory for airplanes subject to the identified unsafe condition. Such modification would terminate the extensive repetitive inspections and/or corrective actions of the protective half-shell (area 1) to detect wear or debonding, and of the trunnion (area 2) to detect wear.

Explanation of Relevant Service Information

Airbus has issued Service Bulletin A320-27-1117, Revision 02, dated January 18, 2000, which describes procedures for modification of the sliding panel mechanism of the flap drive trunnion. Revision 02 is essentially equivalent to previous revisions of the service bulletin (which were cited in AD 99-17-11 as appropriate sources of service information for accomplishment of the modification). However, certain work procedures have been clarified in Revision 02. Accomplishment of this modification would eliminate the need for repetitive inspections. The DGAC approved this service bulletin and issued French airworthiness directive 1996-271-092(B) R3, dated August 11, 1999, in order to assure the continued airworthiness of these airplanes in France.

Airbus also has issued Service Bulletin A320-27-1108, Revision 04, dated November 22, 1999, which describes procedures for repetitive detailed visual inspections of the protective half-shell (area 1) to detect wear or debonding, and detailed visual inspections of the trunnion (area 2) to detect wear. This revision is essentially equivalent to previous revisions, which were cited as the appropriate sources of service information for certain inspections required by AD 99-17-11. However, certain references have been revised and certain work procedures have been clarified in this revision.

Airbus also has issued Service Bulletin A320-27-1066, Revision 5, dated June 25, 1999, which describes procedures for repetitive detailed visual inspections of areas 1 and 2 of the inboard flap trunnion to detect wear on the trunnion; and repair or replacement of the trunnion, if necessary. Revision 5 is essentially equivalent to A320-27-1066, Revision 4, dated July 15, 1997 (for Model A320 series airplanes), which was cited as an appropriate source of service information for certain inspections required by AD 99-17-11.

FAA's Conclusions

These airplane models are manufactured in France and are 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 supersede AD 99-17-11 to continue to require the actions specified in that AD, and to require accomplishment of the previously optional terminating action. The actions would be required to be accomplished in accordance with the service bulletins described previously.

The proposed AD also would revise paragraph (a)(3) of the existing AD to clarify which airplanes are affected by that paragraph. As stated in that paragraph, Airbus Model A320 series airplanes “on which Airbus Modification 22881 has been accomplished, and on which Airbus Modification 22841 or the modification specified in Airbus Service Bulletin A320-27-1050 has not been accomplished” should accomplish certain actions. Since Airbus Modification 22881 corresponds to Airbus Service Bulletin A320-27-1050, the statement is contradictory as written, and cannot be literally complied with by operators. Therefore, the FAA is revising paragraph (a)(3) to apply to Airbus Model A320 series airplanes “on which Airbus Modification 22881 (Airbus Service Bulletin A320-27-1050) has been accomplished, and on which Airbus Modification 22841 has not been accomplished.” Paragraph (a)(3) has also been revised to provide operators with additional time in which to accomplish the inspection required by that paragraph. In addition, NOTE 2 of this proposed AD explains the revision to paragraph (a)(3) of AD 99-17-11 to correct the description of airplanes affected by that paragraph.

Differences Between Proposed Rule and Foreign AD

The proposed AD would differ from the parallel French airworthiness directive in that it would mandate the accomplishment of the terminating action for the repetitive inspections. The French airworthiness directive provides for that action as optional. Mandating the terminating action is based on the FAA's determination that long-term continued operational safety will be better assured by modifications or design changes to remove the source of the problem, rather than by repetitive inspections. Long-term inspections may not be providing 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

There are approximately 132 airplanes of U.S. registry that would be affected by this proposed AD.

The actions that are currently required by AD 99-17-11, and retained in this AD, take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $7,920, or $60 per airplane, per inspection cycle.

The new actions that are proposed in this AD action would take approximately 14 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be $110,880, or $840 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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

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.