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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 99-NM-240-AD] 
          - RIN 2120-AA64 

# 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 A300, A300-600, and A310 series airplanes, that currently requires inspections to detect cracks in the lower spar axis of the nacelle pylon between ribs 9 and 10, and repair, if necessary. The existing AD also provides for optional modification of the pylon, which terminates the inspections for Model A300 and A310                               ( print page 21155)                            series airplanes and increases the threshold and repetitive interval of the inspections for Model A300-600 series airplanes. This action would reduce the inspection threshold and require repetitive inspections following accomplishment of the optional modification for Model A310 series airplanes. 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 fatigue cracking, which could result in reduced structural integrity of the lower spar of the pylon.                     

# DATES:

Comments must be received by May 22, 2000. 

# ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-240-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. 

The service information referenced in this AD may be obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. This information may be examined at the 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 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-240-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-240-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. 

## Discussion 

On April 28, 1995, the FAA issued AD 95-10-03, amendment 39-9220 (60 FR 25604, May 12, 1995), applicable to certain Airbus Industrie Model A300, A300-600, and A310 series airplanes, to require inspections to detect cracks in the lower spar axis of the nacelle pylon between ribs 9 and 10, and repair, if necessary. The existing AD also provides for optional modification of the pylon, which terminates the inspections for Model A300 and A310 series airplanes and increases the threshold and repetitive interval of the inspections for Model A300-600 series airplanes. That action was prompted by reports that fatigue cracks have been found between ribs 9 and 10 on the lower spar of the pylon, initiating at the center stiffener beyond the flat area. The requirements of that AD are intended to prevent such fatigue cracking, which could result in reduced structural integrity of the lower spar of the pylon. 

## Actions Since Issuance of Previous Rule 

                    Since issuance of AD 95-10-03, the Direction Ge                                        ne                                        rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, has advised the FAA that additional cracks have been found in the lower spar axis of the nacelle pylon between ribs 9 and 10 on Model A310 series airplanes at a lower total number of flight cycles than had been earlier reported. Based on these findings, the FAA has determined that, for Airbus Model A310 series airplanes, it is necessary to reduce the inspection threshold and, for airplanes on which the optional modification has been accomplished, to require that the inspections be repetitively performed.                 

## Explanation of Relevant Service Information 

Airbus has issued Service Bulletin A310-54-2016, Revision 02, dated June 11, 1999 (for Model A310 series airplanes). The actions described in Revision 02 of this service bulletin are identical to those described in the original version and Revision 01 (which were cited as appropriate service information for accomplishment of the inspections). Revision 02 was issued to reduce the initial inspection threshold and, for airplanes modified in accordance with Service Bulletin A310-54-2022, Revision 1, dated March 16, 1999, to specify that the inspection be repetitively performed. 

The DGAC classified Service Bulletin A310-54-2016 as mandatory and issued French airworthiness directive 1999-237-285(B), dated June 2, 1999, in order to assure the continued airworthiness of these airplanes in France. French airworthiness directive 1992-049-130(B) R4 was issued to remove Model A310 series airplanes from its applicability and to advise of the issuance of airworthiness directive 1999-237-285(B). 

## 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 95-10-03 to continue to require inspections to detect cracks in the lower spar axis of the nacelle pylon between ribs 9 and 10, and repair, if necessary. The proposed AD would continue to provide for optional modification of the pylon; for Model A300 series airplanes, accomplishment of the modification would terminate the inspections; for Model A300-600 and A310 series airplanes, such                           ( print page 21156)                        modification would increase the threshold and repetitive interval of the inspections.                 

## Differences Between Proposed Rule and Service Bulletins 

Operators should note that, although the service bulletins specify 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 either 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 proposed AD, a repair approved by either the FAA or the DGAC would be acceptable for compliance with this proposed AD. 

## Cost Impact 

The FAA estimates that 140 airplanes of U.S. registry will be affected by this AD. 

It will take approximately 4 work hours per airplane to accomplish the inspection that was previously required by AD 95-10-03, and retained in this AD, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection on U.S. operators is estimated to be $240 per airplane, per inspection cycle. 

The total cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. 

Should an operator elect to accomplish the proposed optional modification, it would take approximately 104 work hours (52 work hours per pylon) to accomplish it, at an average labor rate of $60 per work hour. The cost of required parts would be approximately $1,200 per airplane. Based on these figures, the total cost impact of the optional modification is estimated to be $7,440 per airplane. 

## 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. 

§ 39.13 

2. Section 39.13 is amended by removing amendment 39-9220 (60 FR 25604, May 12, 1995), and by adding the following new airworthiness directive (AD), to read as follows: 

**Airbus Industrie:**                                 Docket 99-NM-240-AD. Supersedes AD 95-10-03, Amendment 39-9220.                            

*Applicability:*                                 The following airplanes, certificated in any category:                             
        - Model A300 series airplanes, as listed in Airbus Service Bulletin A300-54-071, Revision 1, dated October 15, 1993
        - Model A300-600 series airplanes, as listed in Airbus Service Bulletin A300-54-6011, Revision 1, dated October 15, 1993
        - Model A310 series airplanes, as listed in Airbus Service Bulletin A310-54-2016, Revision 02, dated June 11, 1999

# 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 prevent fatigue cracking, which could result in reduced structural integrity of the lower spar of the pylon, accomplish the following: 

## Restatement of Certain Requirements of AD 95-10-03 

### Model A300 Series Airplanes 

(a) For Model A300 B4-2C, B2K-3C, B2-203, B4-103, and B4-203 series airplanes: Prior to the accumulation of 9,000 total landings, or within 500 landings after June 12, 1995 (the effective date of AD 95-10-03, amendment 39-9220), whichever occurs later, perform an internal eddy current inspection to detect cracks in the lower spar axis of the pylon between ribs 9 and 10, in accordance with Airbus Industrie Service Bulletin A300-54-071, dated November 12, 1991; or Revision 1, dated October 15, 1993. 

(1) If no crack is found, repeat the inspection thereafter at intervals not to exceed 2,500 landings. 

(2) If any crack is found that is less than or equal to 30 mm: Perform subsequent inspections and repair in accordance with the methods and times specified in the service bulletin. 

                                (3) If any crack is found that is greater than 30 mm, but less than 100 mm: Prior to the accumulation of 250 landings after crack discovery, repair in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate; or the Direction Ge                                                                ne                                                                rale de l'Aviation Civile (DGAC) (or its delegated agent).                             

(4) If any crack is found that is greater than or equal to 100 mm: 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). 

(5) Accomplishment of the modification specified in Airbus Industrie Service Bulletin A300-54-0079, dated October 15, 1993, constitutes terminating action for the inspections required by paragraph (a) of this AD. 

### Model A300-600 Series Airplanes 

(b) For Model A300-600 B4-620, C4-620, B4-622R, and B4-622 series airplanes: Except as provided by paragraph (b)(5) of this AD, prior to the accumulation of 4,000 total landings, or within 500 landings after June 12, 1995 (the effective date of AD 95-10-03), whichever occurs later, perform an internal eddy current inspection to detect cracks in the lower spar axis of the pylon between ribs 9 and 10, in accordance with Airbus Industrie Service Bulletin A300-54-6011, dated November 12, 1991, as amended by Service Bulletin Change Notice O.A., dated July 10, 1992; or Revision 1, dated October 15, 1993. 

(1) If no crack is found, repeat the inspection thereafter at intervals not to exceed 2,500 landings. 

                                (2) If any crack is found that is less than or equal to 30 mm: Perform subsequent inspections and repair in accordance with                                       ( print page 21157)                                    the methods and times specified in the service bulletin.                             

                                (3) If any crack is found that is greater than 30 mm, but less than 100 mm: Prior to the accumulation of 250 landings after crack discovery, repair in accordance with a method approved by the Manager, International Branch, ANM-116; or the Direction Ge                                                                ne                                                                rale de l'Aviation Civile (DGAC) (or its delegated agent).                             

(4) If any crack is found that is greater than or equal to 100 mm: 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). 

(5) Accomplishment of the modification specified in Airbus Industrie Service Bulletin A300-54-6019, dated October 15, 1993, increases the threshold and repetitive interval of the inspections required by paragraph (b) of this AD to the threshold and interval specified in paragraph 2.D. of the Accomplishment Instructions of Airbus Industrie Service Bulletin A300-54-6011, Revision 1, dated October 15, 1993. 

## New Requirements of This AD 

### Model A310 Series Airplanes 

(c) For Model A310-221, -222, -322, -324, and -325 series airplanes: Perform an internal eddy current inspection to detect cracks in the lower spar axis of the pylon between ribs 9 and 10, in accordance with Airbus Industrie Service Bulletin A310-54-2016, dated November 12, 1991; or Revision 1, dated October 15, 1993; or Revision 2, dated June 11, 1999; at the time specified in paragraph (d) of this AD. 

(1) If no crack is found, repeat the inspection thereafter at intervals not to exceed 2,500 landings. 

(2) If any crack is found that is less than or equal to 30 mm: Perform subsequent inspections and repair in accordance with the methods and times specified in the service bulletin. 

(3) If any crack is found that is greater than 30 mm, but less than 100 mm: Prior to the accumulation of 250 landings after crack discovery, repair in accordance with a method approved by the Manager, International Branch, ANM-116; or the DGAC (or its delegated agent). 

(4) If any crack is found that is greater than or equal to 100 mm: 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). 

(5) Accomplishment of the modification specified in Airbus Industrie Service Bulletin A310-54-2022, dated October 15, 1993; or Revision 1, dated March 16, 1999; increases the threshold and repetitive interval of the inspections required by paragraph (c) of this AD to the threshold and interval specified in paragraph 2.D. of the Accomplishment Instructions of Airbus Industrie Service Bulletin A310-54-2016, Revision 02, dated June 11, 1999. 

(d) Perform the initial inspection required by paragraph (c) of this AD at the earlier of the times specified by paragraphs (d)(1) and (d)(2) of this AD. 

(1) Prior to the accumulation of 25,000 total landings, or within 500 landings after June 12, 1995, whichever occurs later. 

(2) At the applicable time specified by paragraph (d)(2)(i), (d)(2)(ii), or (d)(2)(iii) of this AD. 

(i) For airplanes that have accumulated fewer than 10,000 landings as of the effective date of this AD: Perform the inspection prior to the accumulation of 3,800 total landings, or within 1,500 landings after the effective date of this AD, whichever occurs later. 

(ii) For airplanes that have accumulated 10,000 total landings or more, but fewer than 20,000 total landings, as of the effective date of this AD: Perform the inspection within 1,000 landings after the effective date of this AD. 

(iii) For airplanes that have accumulated 20,000 total landings or more as of the effective date of this AD: Perform the inspection within 500 landings after the effective date of this AD. 

### Alternative Methods of Compliance 

(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, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116. 

# Note 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.

## Special Flight Permits 

(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 1999-237-285(B), dated June 2, 1999.

Issued in Renton, Washington, on April 14, 2000. 

Charles D. Huber, 

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 00-9898 Filed 4-19-00; 8:45 am] 

BILLING CODE 4910-13-P