Airworthiness directives: Airbus,

[Federal Register: July 21, 1998 (Volume 63, Number 139)]

[Proposed Rules]

[Page 39045-39050]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr21jy98-17]

[[Page 39045]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-275-AD]

RIN 2120-AA64

Airworthiness Directives; Airbus Model A310 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 A310 series airplanes, that would have required various inspections to detect fatigue cracks at certain locations on the fuselage, horizontal stabilizer, and wings and tail, and repair or modification, if necessary; and installation of doublers. That proposal was prompted by results of full-scale fatigue testing of a ModelA310 series airplane, which revealed fatigue cracks at those locations. This new action revises the proposed rule by adding new inspections and reducing certain inspection intervals. The actions specified by this new proposed AD are intended to prevent reduced structural integrity of the fuselage, horizontal stabilizer, and wings.

DATES: Comments must be received by August 17, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 95-NM-275-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 LindAvenue, 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-275-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-275-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 A310 series airplanes, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on January 11, 1996 (61 FR 1017). That NPRM would have required various inspections to detect fatigue cracks at certain locations on the fuselage, horizontal stabilizer, and wings and tail, and repair or modification, if necessary; and installation of doublers. That NPRM was prompted by results of full-scale fatigue testing of a Model A310 series airplane, which revealed fatigue cracks at those locations. That condition, if not corrected, could result in reduced structural integrity of the fuselage, horizontal stabilizer, and wings.

Disposition of Comments

Due consideration has been given to the comments received in response to the NPRM.

Request to Cite Revised Service Information

Airbus requests that the FAA revise the proposal to reference later revisions of certain service bulletins, and French airworthiness directive 92-106-132(B)R4, dated June 5, 1996. In addition, Airbus indicates that two additional inspection tasks have been added in Revision 4 of the French airworthiness directive. These tasks are described in two Airbus service bulletins:

‹bullet› Airbus Service Bulletin A310-57-2064, dated August 24, 1995, which describes procedures for repetitive eddy current inspections to detect cracking of the corner angle fitting and the vertical tee fitting at left and right frame 40, and corrective actions, if necessary.

‹bullet› Airbus Service Bulletin A310-57-2038, Revision 2, dated January 4, 1996, which describes procedures for repetitive high frequency eddy current or X-ray inspections to detect cracking of the stringer runouts inboard and outboard of rib 14 at stringers 6, 7, 8, and 9.

In addition, Airbus issued the following service bulletin revisions, which are essentially the same as the previous issues of the service bulletins, except as specified below:

‹bullet› Service Bulletin A310-53-2014, Revision 5, dated June 9, 1992; as revised by Service Bulletin Change Notices 5.A., dated September 29, 1992, and 5.B., dated February 5, 1996; which specifies a reduced inspection threshold, and updates the reference to the appropriate French airworthiness directive.

‹bullet› Service Bulletin A310-53-2059, Revision 1, dated January 4, 1996, which specifies appropriate grace periods for the specified compliance time for accomplishment of the recommended inspections, and updates the reference to the appropriate French airworthiness directive.

‹bullet› Service Bulletin A310-57-2002, Revision 2, dated January 4, 1996, which provides a grace period for the specified compliance time for accomplishment of the recommended inspection.

‹bullet› Service Bulletin A310-57-2006, Revision 3, dated May 2, 1996, which revises the effectivity listing of the service bulletin.

‹bullet› Service Bulletin A310-57-2032, Revision 3, dated January 4, 1996, which revises the effectivity listing of the service bulletin.

[[Page 39046]]

‹bullet› Service Bulletin A310-57-2037, Revision 3, dated January 4, 1996, which contains minor editorial changes.

‹bullet› Service Bulletin A310-57-2046, Revision 4, dated October 16, 1996; as revised by Service Bulletin Change Notice 4A, dated October 16, 1996; which changes the inspection technique, reduces the repetitive inspection intervals, and revises the effectivity listing of the service bulletin.

‹bullet› Service Bulletin A310-57-2047, Revision 2, dated January 22, 1997, which revises the effectivity listing of the service bulletin.

‹bullet› Service Bulletin A310-57-2050, dated April 23, 1990; as revised by Service Bulletin Change Notices 0.A., dated September 29, 1992, and 0.B., dated January 6, 1995; which adds a reference to the appropriate French airworthiness directive.

The Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, classified these service bulletins as mandatory, and issued French airworthiness directive 92-106- 132(B)R4, dated June 5, 1996, in order to ensure the continued airworthiness of these airplanes in France.

The FAA concurs with the commenter's request to cite the additional and revised service bulletins, and has revised this supplemental NPRM to provide these references. Additionally, the cost impact information, below, has been revised to reflect any additional costs to operators and to update the number of affected U.S.-registered airplanes.

Request to Substantiate Need for Accomplishment of Service Bulletins

One commenter questions whether each of the service bulletins cited in the NPRM individually satisfies the unsafe condition requirements of part 39 of the Federal Aviation Regulations (14 CFR part 39). The commenter points out that Airbus Service Bulletin A310-53-2014 indicates that the existence of a ``crack does not affect aircraft safety because its propagation ... could entail expensive repair.''

The commenter further states that the supplementary comments (of the proposed rule) describe how the DGAC allows either a visual or eddy current inspection to detect cracks that measure 0.078 inch, but since the FAA has concluded that a 0.078-inch crack will not likely be found by visual means, the FAA proposes that only an eddy current inspection be used for the affected structure. The commenter states that this restriction goes beyond what is specified by the DGAC and should be substantiated. The commenter states that it suspects that the DGAC is well aware that a 0.078-inch crack would not be found by a visual inspection, but has concluded that a crack of that size on the affected structure does not render the airplane unsafe and that visual inspections are appropriate for the inspection interval provided.

The commenter suggests that if the justification for this proposed AD is based upon the DGAC recommendation, then the FAA's departure from the DGAC's recommendation should be coordinated with the DGAC before the FAA adopts this proposed AD.

The FAA infers that the commenter is requesting substantiation that accomplishment of all of the service bulletins referenced in the proposed AD is necessary in order to address an unsafe condition. The FAA also infers that the example cited regarding visual versus eddy current inspections is in reference to Airbus Service Bulletin A310-57- 2039, dated September 24, 1990.

The wing, fuselage, and empennage structure is primary structure of the airplane that contributes significantly to carrying flight, ground, and pressurization loads. As in much of commercial aircraft structure, the failure of a single part is usually not catastrophic, and safe flight could likely continue for some time with any single part cracked or broken. However, if certain parts (as referenced in the service bulletins) were to fail, the residual strength of the surrounding aircraft structure would be reduced and could cause failure or initiate/accelerate cracking of other structural members. Therefore, in consonance with the DGAC, the FAA finds that accomplishment of the referenced service bulletins, as required by this supplemental NPRM, is necessary in order to adequately address the identified unsafe condition.

However, the FAA has reconsidered its position concerning the use of visual inspection techniques, specifically for accomplishment of the actions specified in Airbus Service Bulletin A310-57-2039 and A310-57- 2050. The FAA finds that a visual inspection also will adequately detect cracking. Operators should note, however, that by the time cracking has progressed to the point of being visually detectable, repairs would likely be complicated and expensive. Since definitive repairs beyond a certain crack length are not provided in the service bulletins, an FAA-approved repair would be required to be accomplished for such cracking. The FAA has revised paragraphs (l) and (p) of this supplemental NPRM to add a visual inspection method as an option for accomplishment of the referenced service bulletins.

Reformatting of the Supplemental NPRM

Operators should note that the FAA has revised the text of paragraphs (a) through (q) of the original NPRM for the sake of brevity and to reduce the complexity of the requirements specified in those paragraphs.

Conclusion

Since certain changes explained previously 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.

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 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 supplemental NPRM would require accomplishment of the actions specified in the service bulletins described previously, except as discussed below.

Differences Between This Supplemental NPRM and the Service Bulletins

Operators should note that, unlike the procedures described in Airbus Service Bulletins A310-57-2002, Revision 2, dated January 4, 1996; A310-57-2006, Revision 3, dated May 2, 1996; A310-57-2032, Revision 3, dated January 4, 1996; and A310-57-2037, Revision 3, dated January 4, 1996; this supplemental NPRM would not permit further flight if cracks are detected in the wing skins. The FAA has determined that, because of the safety implications and consequences associated with such cracking, any wing skin that is found to be cracked must be repaired or modified prior to further flight.

[[Page 39047]]

Additionally, operators should note that, although certain service bulletins specify that the manufacturer may be contacted for disposition of certain repair conditions, this supplemental NPRM would require the repair of those conditions to be accomplished in accordance with a method approved by either the FAA or the DGAC (or its delegated agent). In light of the type of repairs 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, repairs approved by either the FAA or the DGAC (or its delegated agent) would be acceptable for compliance with this supplemental NPRM.

Cost Impact

The FAA estimates that 36 airplanes of U.S. registry would be affected by this AD. Approximate work hours to accomplish the proposed actions and costs for required parts are listed in the following table. The average labor rate is $60 per work hour.

A310

Parts cost/ Cost/ No. of U.S. Number Service bulletin No.

Work hours Airplane Airplane airplanes modified

53-2014.....................................

78

$12,121 $16,801

7

5 53-2016.....................................

317

14,282 33,302

12

5 53-2054.....................................

11

N/A

660

8

0 53-2057.....................................

12

N/A

720

13

0 53-2059.....................................

13

N/A

780

17

0 53-2074.....................................

232

N/A 13,920

17

0 55-2002.....................................

715

34,100 77,000

7

6 55-2004.....................................

16

N/A

960

11

0 57-2002.....................................

8

N/A

480

6

0 57-2006.....................................

52

N/A

3,120

2

0 57-2032.....................................

5

N/A

300

6

0 57-2037.....................................

2

N/A

120

6

0 57-2039.....................................

3

N/A

180

15

0 57-2046.....................................

172

N/A 10,320

33

0 57-2047.....................................

82

N/A

4,920

24

0 57-2050.....................................

24

N/A

1,440

20

0 57-2064.....................................

8

N/A

480

26

0 57-2038.....................................

6

N/A

360

0

0

Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $1,845,591. However, the FAA has been advised that a certain number of U.S.-registered airplanes already have been modified in accordance with the requirements of this AD. (The numbers of U.S.- registered airplanes that have already been modified are listed under the heading, ``Number Modified,'' in the table above.) Therefore, the future economic cost impact of this rule on U.S. operators is now $1,133,076.

The FAA recognizes that the obligation to maintain aircraft in an airworthy condition is vital, but sometimes expensive. Because AD's require specific actions to address specific unsafe conditions, they appear to impose costs that would not otherwise be borne by operators. However, because of the general obligation of operators to maintain aircraft in an airworthy condition, this appearance is deceptive. Attributing those costs solely to the issuance of this supplemental NPRM is unrealistic because, in the interest of maintaining safe aircraft, prudent operators would accomplish the required actions even if they were not required to do so by the supplemental NPRM.

A full cost-benefit analysis has not been accomplished for this supplemental NPRM. As a matter of law, in order to be airworthy, an aircraft must conform to its type design and be in a condition for safe operation. The type design is approved only after the FAA makes a determination that it complies with all applicable airworthiness requirements. In adopting and maintaining those requirements, the FAA has already made the determination that they establish a level of safety that is cost-beneficial. When the FAA, as in this supplemental NPRM, makes a finding of an unsafe condition, this means that the original cost-beneficial level of safety is no longer being achieved and that the proposed actions are necessary to restore that level of safety. Because this level of safety has already been determined to be cost-beneficial, a full cost-benefit analysis for this supplemental NPRM would be redundant and unnecessary.

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

[[Page 39048]]

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.

   Sec. 39.13 [Amended]

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

   Airbus Industrie: Docket 95-NM-275-AD.

   Applicability: All Model A310 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 (u) 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 reduced structural integrity of the fuselage, horizontal stabilizer, and wings, accomplish the following:

   (a) For airplanes listed in Airbus Service Bulletin A310-53- 2014, Revision 5, dated June 9, 1992, as revised by Service Bulletin Change Notices 5.A., dated September 29, 1992, and 5.B., dated February 5, 1996: Prior to the accumulation of 12,000 total flight cycles, or within 500 flight cycles after the effective date of this AD, whichever occurs later, perform an eddy current inspection to detect cracks on the fuselage center section doublers at frame 40, and install new doublers, in accordance with Airbus Service Bulletin A310-53-2014, Revision 5, dated June 9, 1992, as revised by Service Bulletin Change Notices 5.A., dated September 29, 1992, and 5.B., dated February 5, 1996. Except as provided by paragraph (t) of this AD, if any discrepancy is found, prior to further flight, perform follow-on corrective actions, as applicable, in accordance with the service bulletin.

   (b) For airplanes listed in Airbus Service Bulletin A310-53- 2016, Revision 5, dated December 7, 1992: Prior to the accumulation of 12,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, perform a defectoscope or rototest inspection to detect cracks in the area of frame 47 and frame 54, and install new doublers, in accordance with Airbus Service Bulletin A310-53-2016, Revision 5, dated December 7, 1992. Except as provided by paragraph (t) of this AD, if any discrepancy is found, prior to further flight, perform follow-on corrective actions, as applicable, in accordance with the service bulletin.

   (c) For airplanes listed in Airbus Service Bulletin A310-53- 2054, Revision 2, dated May 22, 1990: Prior to the accumulation of 12,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 3,000 flight cycles, perform a visual inspection to detect cracks on frame 46 between the left- and right- hand sides of stringers 21 and 22 on the forward and aft faces in accordance with Airbus Service Bulletin A310-53-2054, Revision 2, dated May 22, 1990. If any crack is found, prior to further flight, repair in accordance with Airbus Service Bulletin A310-53-2054, Revision 2, dated May 22, 1990.

   (1) Accomplishment of the repair required by paragraph (c) of this AD, or modification of the reinforcement angle runout in accordance with Airbus Service Bulletin A310-53-2019, Revision 2, dated May 22, 1990, terminates the repetitive inspection requirements of paragraph (c) of this AD.

   (2) Accomplishment of paragraph (c) of this AD terminates the requirements of AD 91-13-01, amendment 39-7032.

   (d) For airplanes listed in Airbus Service Bulletin A310-53- 2057, Revision 1, dated April 30, 1992: Perform a visual inspection to detect cracks at the T-section connecting frame 50A to the beam between the left- and right-hand sides of frames 50 and 51, in accordance with Airbus Service Bulletin A310-53-2057, Revision 1, dated April 30, 1992. Perform the inspection at the time specified in paragraph (d)(1) or (d)(2) of this AD, as applicable. If any crack is found, prior to further flight, accomplish Airbus Modifications No. 4853 and No. 5273 in accordance with Airbus Service Bulletin A310-53-2057, Revision 1, dated April 30, 1992. Accomplishment of these modifications terminates the requirements of this paragraph.

   (1) For the airplane having manufacturer's serial number (MSN) 191: Prior to the accumulation of 24,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 6,000 flight cycles.

   (2) For airplanes other than the airplane identified in paragraph (d)(1) of this AD: Prior to the accumulation of 12,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 6,000 flight cycles.

   (e) For airplanes listed in Airbus Service Bulletin A310-53- 2059, Revision 1, dated January 4, 1996: Perform a visual inspection to detect cracks in the lower milled side panel at the lap joint with the upper side panel at frame 47 and stringer 22, left- and right-hand sides, in accordance with Airbus Service Bulletin A310- 53-2059, Revision 1, dated January 4, 1996. Perform the inspection at the time specified in paragraph (e)(1) or (e)(2) of this AD, as applicable. Except as provided by paragraph (t) of this AD, if any crack is found, prior to further flight, repair in accordance with the service bulletin. Thereafter, repeat the inspections at intervals not to exceed 9,000 flight cycles, or accomplish Airbus Modification 5997 (Airbus Service Bulletin A310-53-2058). Accomplishment of either the repair or Airbus Modification 5997 constitutes terminating action for the repetitive inspections required by this paragraph.

   (1) For Model A310-200 series airplanes, accomplish the inspection at the time specified in paragraph (e)(1)(i) or (e)(1)(ii) of this AD, as applicable.

   (i) For airplanes that have accumulated less than 20,000 total flight cycles as of the effective date of this AD: Prior to the accumulation of 18,000 total flight cycles, or within 2,000 flight cycles after the effective date of this AD, whichever occurs later.

   (ii) For airplanes that have accumulated 20,000 or more total flight cycles as of the effective date of this AD: Within 1,000 flight cycles after the effective date of this AD.

   (2) For Model A310-300 series airplanes, accomplish the inspection at the time specified in paragraph (e)(2)(i) or (e)(2)(ii) of this AD, as applicable.

   (i) For airplanes that have accumulated less than 19,700 total flight cycles as of the effective date of this AD: Prior to the accumulation of 18,000 total flight cycles, or within 1,700 flight cycles after the effective date of this AD, whichever occurs later.

   (ii) For airplanes that have accumulated 19,700 or more total flight cycles as of the effective date of this AD: Within 850 flight cycles after the effective date of this AD.

   (f) For airplanes listed in Airbus Service Bulletin A310-55- 2002, Revision 4, dated April 28, 1989: Prior to the accumulation of 12,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, perform an eddy current inspection to detect cracks on the upper integral part adjacent to the rear attach fittings on the horizontal stabilizer, and modify the horizontal stabilizer, in accordance with Airbus Service Bulletin A310-55-2002, Revision 4, dated April 28, 1989. Except as provided by paragraph (t) of this AD, if any discrepancy is found, prior to further flight, perform follow-on corrective actions, as applicable, in accordance with the service bulletin.

   (g) For airplanes listed in Airbus Service Bulletin A310-55- 2004, Revision 2, dated February 7, 1991: Perform a high frequency eddy current rototest inspection to detect cracks at specified fastener holes in the top skin chordwise splice along the contour of the steel doubler between ribs 3 and 4 on the left- and right-hand center and side boxes on the horizontal stabilizer in accordance with Airbus Service Bulletin A310-55-2004, Revision 2, dated February 7, 1991, at the time specified in paragraph (g)(1) or (g)(2) of this AD, as applicable. Except as provided by paragraph (t) of this AD, if any discrepancy is found, prior to further flight, perform follow-on corrective actions, as applicable, in accordance with the service bulletin.

   (1) For airplanes on which Airbus Modification A310-4933 (Airbus Service Bulletin A310-55-2002) was accomplished prior to the accumulation of 6,000 total flight cycles on the airplane; or for airplanes having MSN 311 through 414 inclusive, on which Airbus Modification A310-4933 was accomplished during production: Prior to the

   [[Page 39049]]

   accumulation of 18,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 12,000 flight cycles.

   (2) For airplanes on which Airbus Modification A310-4933 (Airbus Service Bulletin A310-55-2002) was accomplished upon or after the accumulation of 6,000 total flight cycles: Prior to the accumulation of 12,000 flight cycles since the modification, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 12,000 flight cycles.

   (h) For airplanes listed in Airbus Service Bulletin A310-57- 2002, Revision 2, dated January 4, 1996: Prior to the accumulation of 12,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 3,000 flight cycles; perform a detailed visual inspection to detect cracks in the external surface of the wing lower skin around the landing access panel holes of the leading edge, in accordance with Airbus Service Bulletin A310-57- 2002, Revision 1, dated July 2, 1992. If any discrepancy is found, 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 Generale de l'Aviation Civile (DGAC) (or its delegated agent). Accomplishment of Airbus Modification 5101 (Airbus Service Bulletin A310-57-2003) terminates the repetitive inspection requirements of paragraph (h) of this AD.

   (i) For airplanes listed in Airbus Service Bulletin A310-57- 2006, Revision 3, dated May 2, 1996: Prior to the accumulation of 6,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 3,000 flight cycles; perform an eddy current inspection to detect cracks in the holes around the overwing refueling aperture at ribs 13-14, in accordance with Airbus Service Bulletin A310-57-2006, Revision 3, dated May 2, 1996. Except as provided by paragraph (t) of this AD, if any discrepancy is found, prior to further flight, perform follow-on corrective actions, as applicable, in accordance with the service bulletin. Accomplishment of Airbus Modification 5891H5128 (Airbus Service Bulletin A310-57- 2020) terminates the repetitive inspection requirements of paragraph (i) of this AD.

   (j) For airplanes listed in Airbus Service Bulletin A310-57- 2032, Revision 3, dated January 4, 1996: Prior to the accumulation of 12,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 4,500 flight cycles; perform a detailed visual inspection to detect cracks around the bolts in the wing top skin upper surface of the front spar between rib 7 and rib 28, in accordance with Airbus Service Bulletin A310-57-2032, Revision 3, dated January 4, 1996. If any discrepancy is found, prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, or the DGAC (or its delegated agent). Accomplishment of Airbus Modification 5026H0878 (Airbus Service Bulletin A310-57-2005) terminates the repetitive inspection requirements of paragraph (j) of this AD.

   (k) For airplanes listed in Airbus Service Bulletin A310-57- 2037, Revision 3, dated January 4, 1996: Prior to the accumulation of 12,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 3,000 flight cycles; perform a high frequency eddy current inspection to detect cracks around the attachment bolt heads for the shroud panel landing on the bottom skin aft of the rear spar, forward of access door 575CB/675CB, in accordance with Airbus Service Bulletin A310-57-2037, Revision 3, dated January 4, 1996. If any discrepancy is found, prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, or the DGAC (or its delegated agent). Accomplishment of Airbus Modification 5106H0894 (Airbus Service Bulletin A310-57-2004) terminates the repetitive inspection requirements of paragraph (k) of this AD.

   (l) For airplanes listed in Airbus Service Bulletin A310-57- 2039, dated September 24, 1990: Perform either an eddy current or visual inspection to detect cracks on the left and right vertical posts, numbers 1 through 5 inclusive, in the wing center box at frame 40/41, in accordance with Airbus Service Bulletin A310-57- 2039, dated September 24, 1990. Perform the inspection at the time specified in paragraph (l)(1) or (l)(2) of this AD, as applicable. Except as provided by paragraph (t) of this AD, if any crack is found, prior to further flight, accomplish the modification specified in Airbus Service Bulletin A310-57-2041, dated September 24, 1990, in accordance with Airbus Service Bulletin A310-57-2039, dated September 24, 1990.

   (1) For airplanes on which Airbus Modification 7541/S7973 (reference Airbus Service Bulletin A310-57-2041) has not been accomplished: Inspect prior to the accumulation of 21,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 4,200 flight cycles (for a visual inspection), or 7,500 flight cycles (for an eddy current inspection).

   (2) For airplanes on which Airbus Modification 7541/S7973 (reference Airbus Service Bulletin A310-57-2041) has been accomplished: Inspect at the time specified in the graph contained in Note 1 of paragraph 1.A.(2) of Airbus Service Bulletin A310-57- 2039, dated September 24, 1990, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 5,000 flight cycles (for a visual inspection), or 8,600 flight cycles (for an eddy current inspection).

   (m) For Model A310-200 series airplanes on which Airbus Modification 7925H1113 has not been accomplished: Prior to the accumulation of 12,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, perform an ultrasonic inspection to detect cracks in certain bolt holes where the main landing gear forward pick-up fitting is attached to the rear spar, in accordance with Airbus Service Bulletin A310-57-2046, Revision 4, dated October 16, 1996 (including Appendix 1, Revision 3, dated October 17, 1995), as revised by Service Bulletin Change Notice 4A, dated October 16, 1996. Accomplishment of paragraph (m) of this AD terminates the requirements of AD 91-06-18, amendment 39-6940.

   (1) If no crack is found, accomplish either paragraph (m)(1)(i) or (m)(1)(ii) of this AD in accordance with the service bulletin at the time specified in that paragraph.

   (i) Repeat the inspection of the bolt/stud holes thereafter at intervals not to exceed 3,500 flight cycles. Or

   (ii) Prior to further flight, accomplish Airbus Modification 7925H1113; and, prior to the accumulation of 18,000 flight cycles after accomplishment of Airbus Modification 7925H1113, perform the inspection required by paragraph (m) of this AD. Repeat the inspection thereafter at intervals not to exceed 11,600 flight cycles.

   Note 2: Airbus Service Bulletin A310-57-2046, Revision 4, dated October 16, 1996 (including Appendix 1, Revision 3, dated October 17, 1995), as revised by Service Bulletin Change Notice 4A, dated October 16, 1996, references Airbus Service Bulletin A310-57-2049 and Repair Instruction R571-49305 as additional sources of service information for accomplishment of Airbus Modification 7925H1113.

   (2) If any crack is found, prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, or the DGAC (or its delegated agent).

   (n) For Model A310-300 series airplanes on which Airbus Modification 7925H1113 has not been accomplished: Prior to the accumulation of 9,000 flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, perform an ultrasonic inspection to detect cracks in certain bolt holes where the main landing gear forward pick-up fitting is attached to the rear spar, in accordance with Airbus Service Bulletin A310-57- 2046, Revision 4, dated October 16, 1996 (including Appendix 1, Revision 3, dated October 17, 1995), as revised by Service Bulletin Change Notice 4A, dated October 16, 1996. Accomplishment of paragraph (n) of this AD terminates the requirements of AD 91-06-18, amendment 39-6940.

   (1) If no crack is found, accomplish either paragraph (n)(1)(i) or (n)(1)(ii) of this AD in accordance with the service bulletin at the time specified in that paragraph.

   (i) Repeat the inspection of the bolt/stud holes thereafter at intervals not to exceed 3,100 flight cycles. Or

   (ii) Prior to further flight, accomplish Airbus Modification 7925H1113; and, prior to the accumulation of 18,000 flight cycles after accomplishment of Airbus Modification 7925H1113, perform the inspection required by paragraph (n) of this AD. Repeat the inspection thereafter at intervals not to exceed 11,600 flight cycles.

   Note 3: Airbus Service Bulletin A310-57-2046, Revision 4, dated October 16, 1996 (including Appendix 1, Revision 3, dated

   [[Page 39050]]

   October 17, 1995), as revised by Service Bulletin Change Notice 4A, dated October 16, 1996, references Airbus Service Bulletin A310-57- 2049 and Repair Instruction R571-49305 as additional sources of service information for accomplishment of Airbus Modification 7925H1113.

   (2) If any crack is found, prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM-116, or the DGAC (or its delegated agent).

   (o) For airplanes listed in Airbus Service Bulletin A310-57- 2047, Revision 2, dated January 22, 1997: Perform a rotating probe inspection to detect cracks in the fastener holes on the left-and right-hand sides of the rear spar internal angle and tee fitting, in accordance with Airbus Service Bulletin A310-57-2047, Revision 2, dated January 22, 1997, at the applicable time specified in Note 2 of paragraph 1.A.(2) of the service bulletin, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at the intervals specified in Note 2 of paragraph 1.A.(2) of the service bulletin. Except as provided by paragraph (t) of this AD, if any discrepancy is found, prior to further flight, perform follow-on corrective actions in accordance with the service bulletin.

   (p) For airplanes listed in Airbus Service Bulletin A310-57- 2050, dated April 23, 1990, as revised by Service Bulletin Change Notices 0.A., dated September 29, 1992, and 0.B., dated January 6, 1995: Perform a visual or rotating probe inspection to detect cracks in the drain holes on the lower skin panel in the center wing box between frames 42 and 46, in accordance with Airbus Service Bulletin A310-57-2050, dated April 23, 1990, as revised by Service Bulletin Change Notices 0.A., dated September 29, 1992, and 0.B., dated January 6, 1995, at the applicable time specified in Note 1 of paragraph 1.A.(2) of the service bulletin, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed those specified in Note 1 of paragraph 1.A.(2) of the service bulletin. Except as provided by paragraph (t) of this AD, if any discrepancy is found, prior to further flight, perform follow-on corrective actions in accordance with the service bulletin. Accomplishment of Airbus Modification number 6130S6815 (Airbus Service Bulletin A310-57-2048), constitutes terminating action for the repetitive inspections required by paragraph (p) of this AD.

   (q) For airplanes listed in Airbus Service Bulletin A310-53- 2074, Revision 1, dated February 20, 1995: Perform visual and eddy current inspections to detect damaged sealant, corrosion, and cracks in accordance with Airbus Service Bulletin A310-53-2074, Revision 1, dated February 20, 1995. Accomplish these requirements at the applicable time specified in Table 2 of paragraph 1.C.(4) of the service bulletin, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed those specified in Table 2 of paragraph 1.C.(4) of the service bulletin, as applicable. Except as provided by paragraph (t) of this AD, if any discrepancy is found, prior to further flight, perform follow-on corrective actions in accordance with the service bulletin.

   (r) For airplanes listed in Airbus Service Bulletin A310-57- 2064, dated August 24, 1995: Perform an eddy current inspection to detect cracks of the upper corner angle fitting and the vertical tee fitting at left and right frame 40, in accordance with Airbus Service Bulletin A310-57-2064, dated August 24, 1995. Perform the inspection at the time specified in paragraph (r)(1) or (r)(2) of this AD, as applicable. Except as provided by paragraph (t) of this AD, if any crack is found, prior to further flight, perform corrective actions in accordance with the service bulletin.

   (1) For Model A310-200 series airplanes: Prior to the accumulation of 18,000 total flight cycles, or within 2,000 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 11,000 flight cycles.

   (2) For Model A310-300 series airplanes: Prior to the accumulation of 18,000 total flight cycles, or within 1,700 flight cycles after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 7,700 flight cycles.

   (s) For airplanes listed in Airbus Service Bulletin A310-57- 2038, Revision 2, dated January 4, 1996: Prior to the accumulation of 12,000 total flight cycles, or within 1,500 flight cycles after the effective date of this AD, whichever occurs later, perform a high frequency eddy current (HFEC) or X-ray inspection to detect cracking of the stringer runouts inboard and outboard of rib 14 at stringers 6, 7, 8, and 9, in accordance with Airbus Service Bulletin A310-57-2038, Revision 2, dated January 4, 1996. Thereafter, repeat the inspection at intervals not to exceed those specified in paragraph 1.B.(5) of the service bulletin, as applicable. If any crack is detected, prior to further flight, repair in accordance with a method approved by the Manager, International Branch, ANM- 116, or the DGAC (or its delegated agent).

   (t) If any crack is found during any inspection required by this AD, and 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, or the DGAC (or its delegated agent).

   (u) 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.

   Note 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

   (v) 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 5: The subject of this AD is addressed in French airworthiness directive 92-106-132(B)R4, dated June 5, 1996.

   Issued in Renton, Washington, on July 14, 1998. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 98-19332Filed7-20-98; 8:45 am]

   BILLING CODE 4910-13-P