Airworthiness directives: Airbus,
[Federal Register: September 15, 1998 (Volume 63, Number 178)]
[Proposed Rules]
[Page 49309-49312]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr15se98-29]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-NM-29-AD]
RIN 2120-AA64
Airworthiness Directives; Airbus Model A319, A320, and A321 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Supplemental notice of proposed rulemaking; reopening of comment period.
SUMMARY: This document revises an earlier proposed airworthiness directive (AD), applicable to certain Airbus Model A320 series airplanes, that would have required repetitive inspections to detect wear of the inboard flap trunnions; modification or replacement, if necessary; and eventual modification of the trunnions, which would terminate the repetitive inspections. That proposal was prompted by reports of wear damage found on the inboard flap drive trunnions that was caused by chafing of the Teflon rollers of the chain that actuates the sliding panel of the fairing. This new action revises the proposed AD by adding new repetitive inspections to detect wear or debonding of the protective half-shells, and corrective actions, if necessary; and by removing the modification requirement. This action also would expand the applicability of the existing AD to include additional airplanes. The actions specified by this proposed 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.
DATES: Comments must be received by October 13, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 96-NM-29-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 filedin 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 96-NM-29-AD.'' The postcard will be date stamped and returned to the commenter.
Availability of Notice of Proposed Rulemaking (NPRM)
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. 96-NM-29-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
Discussion
A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to certain Airbus Model A320 series airplanes, was published as an NPRM in the Federal Register on August 30, 1996 (61 FR 45910). That NPRM would have required repetitive inspections to detect wear of the inboard flap trunnions; modification or replacement, if necessary; and eventual modification of the trunnions, which would terminate the repetitive inspections. That NPRM was prompted by reports of wear damage found on the inboard flap drive trunnions that was caused by chafing of the Teflon rollers of the chain that actuates the sliding panel of the fairing. Such chafing and resultant wear damage, if not corrected, 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.
Comments Received
Due consideration has been given to the comments received in response to the NPRM.
Requests To Delete the Proposed Modification
Several commenters request that the FAA delete the modification requirements specified in paragraphs (a)(2), (a)(3), and (b) of the original NPRM. These commenters state that accomplishment of Airbus Service Bulletin A320-27-1050, Revision 3, dated October 21, 1994 (referenced in the original NPRM as the appropriate source of service information for accomplishing the proposed modification of the inboard flap trunnion), does not eliminate the potential for damage to the trunnion and should not be accomplished.
The FAA concurs with the commenters' requests to delete the modification requirement specified in the original NPRM. Since issuance of that NPRM, the Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France,
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advised the FAA that it has received reports of protective half-shells detaching from the inboard flap trunnions, and other reports of wear marks being detected on the protective half-shells on certain A320 series airplanes. These airplanes had been modified in accordance with Airbus Service Bulletin A320-27-1050, Revision 3.
The DGAC further advises the FAA that it also has received reports that the Teflon rollers of the chain that actuates the sliding panel of the fairing have been found displaced and could consequently chafe the unprotected part of the trunnion. In addition, reports indicate that debonding of the protective half-shells was most likely caused by incompatibility between the cleaning solution and the bonding agent.
In light of these findings, the FAA has determined that accomplishment of the modification specified in the original NPRM does not adequately protect the inboard flap trunnion. Therefore, the FAA has deleted the proposed modification requirement from this supplemental NPRM.
Request To Cite New Service Information
Several commenters advise that Airbus has issued Service Bulletin A320-27-1108, Revision 01, dated July 15, 1997 (for Airbus Model A319, A320, and A321 series airplanes on which protective half-shells have been installed). The service bulletin describes procedures for repetitive detailed visual inspections of the trunnions with the protective half-shells. These commenters point out that protective half-shells were installed on certain Airbus Model A319 and A321 series airplanes during production or in accordance with Airbus Service Bulletin A320-27-1097. Therefore, such modified Airbus Model A319 and A321 series airplanes are subject to the same identified unsafe condition as the affected Airbus Model A320 series airplanes.
One of these commenters states that, for airplanes that have not been modified in accordance with Airbus Service Bulletin A320-27-1050, Airbus has issued Revision 3 of Service Bulletin A320-27-1066 that deletes the reference to Airbus Service Bulletin A320-27-1050 and includes a repair solution.
In addition, one commenter states that Airbus has issued Service Bulletin A320-27-1097, which is applicable to Airbus Model A321 series airplanes on which Airbus Modification 23926 has not been accomplished. The commenter also states that Airbus Service Bulletin A320-27-1097 describes repetitive inspections of the trunnion similar to those described in Airbus Service Bulletin A320-27-1066.
The FAA infers that the commenters are requesting that the supplemental NPRM be revised to cite new service information and expand the applicability of the original NPRM. The FAA concurs. Since issuance of the original NPRM, Airbus has issued the following new service bulletins:
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A320-27-1066, Revision 4, dated July 15, 1997 (for Model A320 series airplanes), describes new 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 4 of the service bulletin revises the effectivity listing of earlier revisions of the service bulletin (Revision 1 was referenced in the original NPRM as an appropriate source of service information). Although one commenter requests that the FAA reference Revision 3 of Airbus Service Bulletin A320-27-1066, the FAA has determined that it is appropriate to cite the latest revision of that service bulletin. Therefore, the FAA has revised paragraphs (b) and (c) of the supplemental NPRM to cite Revision 4 of Airbus Service Bulletin A320-27-1066 as an appropriate source of service information.
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A320-27-1097, Revision 01, dated July 15, 1997 (for Model A321 series airplanes), describes essentially identical procedures to those specified in Airbus Service Bulletin A320-27-1066 (discussed above) for Airbus Model A321 series airplanes. The FAA finds that accomplishment of these procedures will adequately detect and correct wear of the inboard trunnion. Therefore, the FAA has revised paragraphs (b) and (c) of the supplemental NPRM to cite Revision 01 of Airbus Service Bulletin A320-27-1097 as an appropriate source of service information.
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A320-27-1108, Revision 01, dated July 15, 1997 (for Model A319, A320, and A321 series airplanes), 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. In addition, this service bulletin describes follow-on corrective actions that include further inspections of the trunnions and/or protective half-shells; repair of the inboard flap trunnion by installing a new protective half-shell of the drive trunnion of the inboard flap, or replacing the existing half-shell; and replacement of the trunnion with a new or serviceable trunnion. The FAA has determined that accomplishment of these follow-on inspections and corrective actions will adequately detect and correct wear of the protective half-shells and the trunnion, and debonding of the protective half-shells. Therefore, the FAA has revised paragraphs (a) and (c) of the supplemental NPRM to cite Revision 01 of Airbus Service Bulletin A320-27-1108 as an appropriate source of service information.
The DGAC classified the Airbus service bulletins as mandatory, and issued French airworthiness directive 96-271-092(B) R1, dated October 8, 1997, in order to assure the continued airworthiness of these airplanes in France.
In addition, because the FAA finds that Airbus Model A319 and A321 series airplanes also are subject to the identified unsafe condition of this proposed AD, the applicability of this supplemental NPRM, and the cost impact information, below, have been revised accordingly.
Differences Between Supplemental NPRM and Service Information
Operators should note that, although the service bulletins specify that the manufacturer may be contacted for disposition of certain wear conditions found on the flap trunnions, this supplemental NPRM would require repair of the wear condition in accordance with a method approved by the FAA, or the DGAC (or its delegated agent). In light of the action that would be required to address the identified unsafe condition, and in consonance with existing bilateral airworthiness agreements, the FAA has determined that a repair approved by either the FAA or the DGAC would be acceptable for compliance with this supplemental NPRM.
Request To Establish an Alternative Compliance Time for Certain Airplanes
One commenter requests that the FAA establish a grace period of 18 months for the compliance time threshold of 10,000 total flight hours specified in paragraph (b) of the original NPRM. The commenter states that no accomplishment period exists for airplanes that have passed the proposed limit, and that all of its Airbus Model A320 series airplanes have accumulated in excess of 11,000 total flight hours. Therefore, operators would be subject to severe operational impact under the compliance time specified by the original NPRM.
The FAA acknowledges that a grace period would have been appropriate; however, as discussed previously, the FAA has deleted the modification requirements specified in paragraphs (a)(2), (a)(3), and (b) of the original NPRM.
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Request to Change the Terminating Action in the Original NPRM
One commenter requests that the terminating action specified in Airbus Service Bulletin A320-27-1050, Revision 3, dated October 21, 1994 [as referenced in paragraph (b) of the original NPRM] be changed to the terminating action specified in Airbus Service Bulletin A320-27- 1117, dated September 16, 1997. The commenter states that this new service bulletin specifies a new design for the protective clamp assembly and sliding fairing, which incorporates a lockwire to the protective clamp assembly and redesigns the sliding fairing to reduce the flexibility of the assembly and reduce the clearance between the trunnion fitting and clamp assembly. The commenter also states that the new design eliminates the potential for damage to the unprotected portion of the trunnion, and that the new, thicker steel wear pads on the clamp assembly are more wear resistant than the half-shell design.
The FAA concurs partially with this request. As discussed previously, the FAA agrees that the modification proposed in accordance with Airbus Service Bulletin A320-27-1050 is not appropriate as a terminating action and has deleted that requirement from this supplemental NPRM. However, the FAA has not approved an alternative terminating action at this time. The DGAC and the manufacturer advise that the modification specified in Airbus Service Bulletin A320-27-1117 is being evaluated to determine whether it is an appropriate terminating action for the repetitive inspections. The DGAC also states that it will provide additional information when the evaluation is completed. If such a modification is determined to be effective in preventing the unsafe condition addressed by this supplemental NPRM, the FAA may consider further rulemaking. However, the FAA considers that it is inappropriate to delay issuance of the supplemental NPRM in order to await completion of the evaluation.
Conclusion
Since these changes expand the scope of the originally proposed AD, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.
Interim Action
This is considered to be interim action. The manufacturer has advised that it currently is developing a modification that will positively address the unsafe condition addressed by this AD. Once this modification is developed, approved, and available, the FAA may consider additional rulemaking.
Cost Impact
The FAA estimates that 132 airplanes of U.S. registry would be affected by this AD, that it would take approximately 1 work hour per airplane to accomplish any of the proposed inspections, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $7,920, or $60 per airplane, per inspection cycle.
The cost impact figure discussed above is 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 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
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
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The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
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Section 39.13 is amended by adding the following new airworthiness directive:
Airbus Industrie: Docket 96-NM-29-AD.
Applicability: All Model A319, A320, and A321 series airplanes; certificated in any category.
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 (e) 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 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, adversely affect the fatigue life of the secondary load path, and lead to loss of the flap; accomplish the following:
(a) For airplanes on which a protective half-shell has been installed over area 1 of the left or right inboard flap trunnion: Perform a detailed visual inspection of the protective half-shell (area 1) to detect wear or debonding, and perform a detailed visual inspection of the trunnion (area 2) to detect wear at the time specified in paragraph (a)(1), (a)(2), or (a)(3) of this AD, as applicable; in accordance with Airbus Service Bulletin A320-27-1108, Revision 01, dated July 15, 1997.
(1) For Model A319 and Model A320 series airplanes on which Airbus Modification 22841 has been installed: Inspect prior to the accumulation of 2,500 flight hours after the incorporation of the modification, or within 500 flight hours after the effective date of this AD, whichever occurs later.
(2) For Model A321 series airplanes on which Airbus Modification 23926 has been installed, or on which the repair specified in Airbus Service Bulletin A320-27-1097, dated October 5, 1996, or Revision 01, dated July 15, 1997, has been accomplished; and for Model A320 series airplanes on which the repair specified in Airbus Service Bulletin A320-27-1066, Revision 3, dated October 30, 1996, or Revision 4, dated July 15, 1997, has been accomplished: Inspect prior to the accumulation of 5,000 flight hours after incorporation of the repair or modification,
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or within 500 flight hours after the effective date of this AD, whichever occurs later.
(3) For 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: Inspect within 500 flight hours after the effective date of this AD.
(b) For airplanes on which no protective half-shell is installed over area 1 of the left or right inboard flap trunnion: Within 500 flight hours after the effective date of this AD, perform a detailed visual inspection of areas 1 and 2 of the inboard flap trunnion to detect wear on the trunnion, in accordance with Airbus Service Bulletin A320-27-1066, Revision 4, dated July 15, 1997 (for Model A320 series airplanes), or A320-27-1097, Revision 01, dated July 15, 1997 (for Model A321 series airplanes).
(c) Except as provided by paragraph (d) of this AD: Following the accomplishment of any inspection required by either paragraph (a) or (b) of this AD, perform the follow-on repetitive inspections and/or corrective actions, as applicable, in accordance with Airbus Service Bulletin A320-27-1066, Revision 4, dated July 15, 1997 (for Model A320 series airplanes); A320-27-1097, Revision 01, dated July 15, 1997 (for Model A321 series airplanes); or A320-27-1108, Revision 01, dated July 15, 1997 (for Model A319, A320, and A321 series airplanes); as applicable; at the compliance times specified in the applicable service bulletin.
(d) If the applicable service bulletin specifies to contact Airbus for an appropriate action, prior to further flight, repair in accordance with a method approved by either the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, or the Direction Gnrale de l'Aviation Civile (or its delegated agent).
(e) 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. Operators shall submit requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.
Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.
(f) 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.
Note 3: The subject of this AD is addressed in French airworthiness directive 96-271-092(B) R1, dated October 8, 1997.
Issued in Renton, Washington, on September 9, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-24656Filed9-14-98; 8:45 am]
BILLING CODE 4910-13-U
