Airworthiness directives: Airbus,
[Federal Register: November 24, 1998 (Volume 63, Number 226)]
[Proposed Rules]
[Page 64918-64921]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24no98-36]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-NM-150-AD]
RIN 2120-AA64
Airworthiness Directives; Airbus Model A300-600 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 all Airbus Model A300-600 series airplanes, that would have required repetitive eddy current inspections to detect cracks on the forward fittings in the radius of frame 40 adjacent to the tension bolts in the center section of the wings, and various follow-on actions. That proposal was prompted by reports of cracking due to fatigue-related stress in the radius of frame 40 adjacent to the tension bolts at the center/outer wing junction. This new action revises the proposed rule by requiring ultrasonic inspections, in lieu of the eddy current inspection proposed previously. This action also reduces the compliance time to perform the initial inspection, increases the repetitive inspection intervals, and adds flight hours as a compliance option. The actions specified by this new proposed AD are intended to detect and correct fatigue cracking on the forward fittings in the radius of frame 40 adjacent to the tension bolts in the center section of the wings, which could result in reduced structural integrity of the wings.
DATES: Comments must be received by December 21, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No 95-NM-150-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.
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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 95-NM-150-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. 95-NM-150-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 all Airbus Model A300-600 series airplanes, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on March 6, 1996 (61 FR 8897). That NPRM would have required repetitive eddy current inspections to detect cracks on the forward fittings in the radius of frame 40 adjacent to the tension bolts in the center section of the wings, and various follow-on actions. That NPRM was prompted by reports of cracking due to fatigue-related stress in the radius of frame 40 adjacent to the tension bolts at the center/outer wing junction. That condition, if not corrected, could result in reduced structural integrity of the wings.
Actions Since Issuance of Previous Proposal
Since the issuance of that NPRM, the FAA has given due consideration to the comments received in response to the NPRM. The comments that have prompted a change in the proposal are explained below.
Request To Reference New Revision of the Service Bulletin
Two commenters [the Air Transport Association (ATA) of America and the manufacturer] request that the FAA revise the proposed AD to reference a new revision of the service bulletin referenced in the proposed AD.
The FAA concurs with the commenters' request to revise the proposed AD to reference a new version of the service bulletin. Since issuance of the NPRM, Airbus has issued Service Bulletin A300-57-6062, Revision 02, dated January 29, 1997. That service bulletin describes procedures for an ultrasonic inspection, in lieu of the eddy current inspection described in the original issue of the service bulletin (which was referenced in the original NPRM as the appropriate source of service information), to detect cracking on the forward fittings in the radius of frame 40 adjacent to the tension bolts in the center section of the wings, and various follow-on actions. If no cracking is detected, those follow-on actions consist of repetitive ultrasonic inspections. If any cracking is detected, the follow-on actions include installation of an access door or doors, repetitive eddy current inspections to confirm the presence of a crack, and blending of the crack or cracks, if necessary. If the blended area is 50 millimeters (mm) long or more, or exceeds 2 mm in depth, the service bulletin provides for repair in accordance with procedures to be provided by Airbus.
The Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, classified Airbus Service Bulletin A300-57-6062, Revision 02, as mandatory and issued a new French airworthiness directive, 95-063-177(B)R3, dated July 2, 1997, in order to assure the continued airworthiness of these airplanes in France.
The FAA finds that accomplishment of the actions specified in Airbus Service Bulletin A300-57-6062, Revision 02, would adequately address the identified unsafe condition, while also providing an inspection method that limits the number of work hours necessary to gain access to the areas to be inspected, thereby minimizing the economic impact of the inspection. Therefore, the FAA has revised the proposed AD to specify Revision 02 of the service bulletin as the appropriate source of service information. The cost impact information of the proposed AD also has been revised to reflect a reduction in the number of work hours necessary to complete the inspection procedure.
Request To Adjust Inspection Thresholds and Intervals
One commenter, the manufacturer, requests that the FAA revise the proposed AD to require inspection thresholds and repetitive intervals to be calculated based on average flight time using the ``adjustment for range'' formula referenced in both the original and revised service bulletins. Such adjustment is designed to account for variations in the amount of fatigue damage due to loading and flight length and may result in reductions in the inspection threshold and intervals.
The FAA does not concur that operators should be required to calculate inspection thresholds and repetitive intervals using the ``adjustment for range'' formula. Use of such a formula would introduce a planning burden for the operator, make enforcement difficult for the FAA, and potentially introduce differences between FAA inspectors and operators concerning when the inspection thresholds and intervals should be recalculated.
However, under the provisions of paragraph (d)(2) of this supplemental NPRM, the FAA may approve requests for adjustment of the inspection thresholds and intervals. The request for extension should be based on the ``adjustment for range'' formula referenced in Airbus Service Bulletin A300-57-6062, Revision 02, and the average flight time per flight cycle used in the formula should be for an individual airplane. Average flight times for a group of airplanes may be used if flight times for all airplanes included in the group do not vary by more than 10
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percent, and the flight times for individual airplanes within the group must be included with the request, for review by the FAA.
The FAA acknowledges, however, that the inspection thresholds and intervals specified in the original proposal may not be conservative, based on the utilization of certain airplanes. Also, French airworthiness directive 95-063-177(B)R3 reduces the inspection threshold specified in the original issue of French airworthiness directive 95-063-177(B), dated April 12, 1995. In consideration of the commenter's request, and in concert with the French airworthiness directive, the FAA has determined that the inspection threshold for this proposal should be reduced from 10,500 total landings, as specified in the original proposal, to 7,250 total landings. The FAA also has determined that the inspection thresholds and intervals may be calculated using flight hours; thus the inspection threshold has been revised to provide for the inspection to be performed prior to the accumulation of 17,700 total flight hours.
The repetitive inspection intervals for this proposal also have been increased from 4,500 landings to 6,500 landings or 16,000 flight hours, for airplanes on which no cracking is detected; and from 950 landings to 2,800 landings or 7,000 flight hours, for certain airplanes on which cracking is detected. Paragraphs (a), (b), and (c)(1) of this supplemental NPRM have been revised to reduce the inspection thresholds, increase the repetitive inspection intervals, and add flight hours as a compliance option.
Differences Between the Supplemental NPRM and Foreign AD
Operators should note that, although the service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, this proposal would require the repair of those conditions to be accomplished in accordance with a method approved by the FAA or the DGAC (or its delegated agent). In light of the type of repair that would be required to address the identified unsafe condition, and in consonance with existing bilateral airworthiness agreements, the FAA has determined that, for this supplemental NPRM, a repair approved by either the FAA or the DGAC would be acceptable for compliance with this supplemental NPRM.
Operators also should note that the inspection thresholds and intervals for this supplemental NPRM differ from those specified in the French airworthiness directive. In developing the appropriate inspection thresholds and intervals for this supplemental NPRM, the FAA considered not only the manufacturer's recommendation and the average utilization rate of the affected U.S. registered airplanes, but the safety implications involved with cracking in the radius of frame 40 adjacent to the tension bolts at the center/outer wing junction. In light of these factors, the FAA finds the proposed compliance time (7,250 total landings or 17,700 total flight hours) specified in the supplemental NPRM for initiating the required actions to be warranted, in that it represents an appropriate interval of time allowable for the affected airplanes to continue to operate without compromising safety.
Conclusion
Since these changes expand the scope of the originally proposed rule, the FAA has determined that it is necessary to reopen the comment period to provide additional opportunity for public comment.
Cost Impact
The FAA estimates that 35 airplanes of U.S. registry would be affected by this proposed AD.
The new inspection method proposed by this supplemental NPRM would not add any new additional economic burden on affected operators, other than, for certain airplanes, the costs that are associated with the initial inspection being required earlier than specified in the original NPRM.
It would take approximately 2 work hours per airplane (1 work hour per side) to accomplish the proposed ultrasonic inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this proposed inspection on U.S. operators is estimated to be $4,200, or $120 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 95-NM-150-AD.
Applicability: All Model A300-600 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 (d)(1) 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 fatigue cracking on the forward fittings in the radius of frame 40 adjacent to the tension bolts in the center section of the wings, which could result in reduced structural integrity of the wings, accomplish the following:
(a) Perform an ultrasonic inspection to detect cracking on the forward fittings in the
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radius of frame 40 adjacent to the tension bolts in the center section of the wings, in accordance with Airbus Service Bulletin A300-57-6062, Revision 02, dated January 29, 1997, at the applicable time specified in either paragraph (a)(1) or (a)(2) of this AD.
(1) For airplanes that have accumulated fewer than 9,100 total landings or 22,300 total flight hours as of the effective date of this AD: Inspect at the later of the times specified in either paragraph (a)(1)(i) or (a)(1)(ii) of this AD.
(i) Prior to the accumulation of 7,250 total landings or 17,700 total flight hours, whichever occurs first.
(ii) Within 1,500 landings after the effective date of this AD.
(2) For airplanes that have accumulated 9,100 total landings or more and 22,300 total flight hours or more as of the effective date of this AD: Inspect within 750 landings after the effective date of this AD.
Note 2: Inspections that were accomplished prior to the effective date of this AD in accordance with Airbus Service Bulletin A300-57-6062, Revision 1, dated July 23, 1995, are considered acceptable for compliance with paragraph (a) of this AD.
(b) If no crack is detected during the inspection required by paragraph (a) of this AD, repeat the ultrasonic inspection required by that paragraph thereafter at intervals not to exceed 6,500 landings or 16,000 flight hours, whichever occurs first; in accordance with Airbus Service Bulletin A300-57-6062, Revision 02, dated January 29, 1997.
(c) If any crack is detected during any inspection required by paragraph (a) or (b) of this AD, prior to further flight, install an access door, and perform an eddy current inspection to confirm the presence of a crack; in accordance with Airbus Service Bulletin A300-57-6062, Revision 02, dated January 29, 1997. Accomplishment of this eddy current inspection terminates the repetitive inspection requirement of paragraph (b) of this AD.
(1) If no crack is detected during the eddy current inspection, repeat the eddy current inspection, in accordance with the service bulletin, thereafter at intervals not to exceed 6,500 landings or 16,000 flight hours, whichever occurs first.
(2) If any crack is detected during any eddy current inspection performed in accordance with paragraph (c) or (c)(1) of this AD, prior to further flight, blend out the crack and repeat the eddy current inspection in accordance with the service bulletin.
(i) If the eddy current inspection performed after the blend-out shows that the crack has been removed, and if the blend-out is equal to or less than 50 millimeters (mm) long and equal to or less than 2 mm deep, thereafter repeat the eddy current inspection at intervals not to exceed 2,800 landings or 7,000 flight hours, whichever occurs first.
(ii) If the eddy current inspection performed after the blend- out shows that the crack has not been removed, or if the blend-out is more than 50 mm long or more than 2 mm deep, prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the Direction Generale de l'Aviation Civile (or its delegated agent).
(d)(1) 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 their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.
(d)(2) Operators may request an extension to the compliance times of this AD in accordance with the ``adjustment-for-range'' formula found in Paragraph 1.B.(5) of Airbus Service Bulletin A300- 57-6062, Revision 02, dated January 29, 1997; and provided in A300- 600 Maintenance Review Board, Section 5, Paragraph 5.4. The average flight time per flight cycle (landing) in hours used in this formula should be for an individual airplane. Average flight time for a group of airplanes may be used if all airplanes of the group have flight times differing by no more than 10 percent. If compliance times are based on the average flight time for a group of airplanes, the flight times for individual airplanes of the group must be included for FAA review.
Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.
(e) 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 4: The subject of this AD is addressed in French airworthiness directive 95-063-177(B)R3, dated July 2, 1997.
Issued in Renton, Washington, on November 18, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-31323Filed11-23-98; 8:45 am]
BILLING CODE 4910-13-U
