Airworthiness directives: Airbus,

[Federal Register: December 9, 1998 (Volume 63, Number 236)]

[Proposed Rules]

[Page 67813-67816]

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

[DOCID:fr09de98-19]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-106-AD]

RIN 2120-AA64

Airworthiness Directives; Airbus Model A300 and A300-600 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

[[Page 67814]]

SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Airbus Model A300 and A300-600 series airplanes. This proposal would require replacement of the rivets that attach the pressurized floor panel to gantries 4 and 5 with new titanium alloy bolts. This proposal also would require, for certain airplanes, repetitive inspections to detect discrepancies of the rivets; and corrective actions, if necessary. 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 failure of the rivets that attach the pressurized floor panel to gantries 4 and 5, which could result in the loss of the floor panel and consequent rapid decompression of the airplane.

DATES: Comments must be received by January 8, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-106-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 98-NM-106-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. 98-NM-106-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition may exist on certain Airbus Model A300 and A300-600 series airplanes. The DGAC advises that, during maintenance on a Model A300 series airplane, maintenance personnel discovered several rivets had been sheared off that attach the pressurized floor panel to gantry 5 between frames 47 and 48. Those rivets are also used to attach the pressurized floor panel to gantry 4. Investigation has revealed that alternate bending stress under the rivet heads caused the rivets to break. The cause of the stress has been attributed to an alternate shear load between the pressurized floor panel and gantries 4 and 5. Failure of the rivets, if not corrected, could result in the loss of the floor panel and consequent rapid decompression of the airplane.

The rivets that attach the pressurized floor panel to gantries 4 and 5 on certain Model A300-600 series airplanes are similar in design to those on Model A300 series airplanes; therefore, both models may be subject to the same unsafe condition.

Explanation of Relevant Service Information

Airbus has issued Service Bulletin A300-53-0331, dated March 18, 1997 (for Model A300 series airplanes), and A300-53-6107, dated March 18, 1997 (for Model A300-600 series airplanes), which describe procedures for replacement of the rivets between frames 47 and 48 at gantries 4 and 5 with new titanium alloy bolts.

For certain airplanes, these service bulletins also describe procedures for repetitive detailed visual inspections to detect discrepancies of the existing rivets; corrective actions, if necessary; and eventual replacement of the plain aluminum rivets or blind rivets with titanium alloy bolts.

Accomplishment of the actions specified in the service bulletins is intended to adequately address the identified unsafe condition. The DGAC classified these service bulletins as mandatory and issued French airworthiness directive 97-176-229(B), dated August 13, 1997, in order to assure the continued airworthiness of these airplanes in France.

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 require replacement of the existing rivets that attach the pressurized floor panel to gantries 4 and 5 with new titanium alloy bolts. For certain airplanes, this proposal would require repetitive inspections to detect discrepancies of the existing rivets; corrective actions, if necessary; and eventual replacement of the plain aluminum rivets or blind rivets that attach the pressurized floor panel to gantries 4 and 5 with titanium alloy bolts.

Cost Impact

The FAA estimates that 24 Airbus Model A300 series airplanes of U.S. registry would be affected by this proposed AD. It would take approximately 26 work hours per

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airplane to accomplish the proposed replacement, at an average labor rate of $60 per work hour. Required parts would cost between $3,160 and $3,520 per airplane, depending on the service kit purchased. Based on these figures, the cost impact of the replacement proposed by this AD on U.S. operators of Airbus Model A300 series airplanes is estimated to be as low as $4,720 per airplane or as high as $5,080 per airplane.

The FAA estimates that 61 Airbus Model A300-600 series airplanes of U.S. registry would be affected by this proposed AD. It would take approximately 26 work hours per airplane to accomplish the proposed replacement, at an average labor rate of $60 per work hour. Required parts would cost between $3,530 and $3,550 per airplane, depending on the service kit purchased. Based on these figures, the cost impact of the replacement proposed by this AD on U.S. operators of Airbus Model A300-600 series airplanes is estimated to be as low as $5,090 per airplane or as high as $5,110 per airplane.

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

Should an operator be required to accomplish the proposed inspection, it would take approximately 1 work hour to accomplish, at an average labor rate of $60 per work hour. Based on this figure, the cost impact of the inspection proposed by this AD on U.S. operators of Airbus Model A300 and A300-600 series airplanes is estimated to be $60 per airplane, per inspection cycle.

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

  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 98-NM-106-AD.

    Applicability: Model A300 and A300-600 series airplanes on which Airbus Modification 11523 (reference Airbus Service Bulletins A300- 53-0331 and A300-53-6107, both dated March 18, 1997) has not been accomplished, certificated in any category.

    Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 (c) 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 failure of the rivets that attach the pressurized floor panel to gantries 4 and 5, which could result in the loss of the floor panel and consequent rapid decompression of the airplane, accomplish the following:

    (a) Accomplish paragraph (a)(1), or paragraphs (a)(2) and (a)(3), of this AD at the times specified in those paragraphs in accordance with Airbus Service Bulletin A300-53-0331, dated March 18, 1997 (for Airbus Model A300 series airplanes); or Airbus Service Bulletin A300-53-6107, dated March 18, 1997 (for Airbus Model A300- 600 series airplanes); as applicable.

    (1) Replace the rivets that attach the pressurized floor panel to gantries 4 and 5 with new titanium alloy bolts, at the applicable time specified in paragraph (a)(1)(i), (a)(1)(ii), (a)(1)(iii), or (a)(1)(iv) of this AD.

    (i) For Airbus Model A300-600 series airplanes, replace the rivets prior to the accumulation of 7,150 total flight cycles.

    (ii) For Airbus Model A300 B4-203 series airplanes, replace the rivets prior to the accumulation of 10,000 total flight cycles.

    (iii) For Airbus Model A300 B4-2C and B4-103 series airplanes, replace the rivets prior to the accumulation of 12,300 total flight cycles.

    (iv) For Airbus Model A300 B2-1C, B2-203, and B2K-3C series airplanes, replace the rivets prior to the accumulation of 14,600 total flight cycles.

    (2) Perform a detailed visual inspection to detect any broken or discrepant rivets that attach the pressurized floor panel to gantries 4 and 5, at the applicable time specified in paragraph (a)(2)(i), (a)(2)(ii), (a)(2)(iii), or (a)(2)(iv) of this AD. Repeat the inspection thereafter at intervals not to exceed 350 flight cycles until accomplishment of the action required by paragraph (a)(3) of this AD.

    (i) For Airbus Model A300-600 series airplanes, inspect the rivets prior to the accumulation of 7,500 total flight cycles, or within 350 flight cycles after the effective date of this AD, whichever occurs later.

    (ii) For Airbus Model A300 B4-203 series airplanes, inspect the rivets prior to the accumulation of 10,350 total flight cycles, or within 350 flight cycles after the effective date of this AD, whichever occurs later.

    (iii) For Airbus Model A300 B4-2C and B4-103 series airplanes, inspect the rivets prior to the accumulation of 12,650 total flight cycles, or within 350 flight cycles after the effective date of this AD, whichever occurs later.

    (iv) For Airbus Model A300 B2-1C, B2-203, and B2K-3C series airplanes, inspect the rivets prior to the accumulation of 14,950 total flight cycles, or within 350 flight cycles after the effective date of this AD, whichever occurs later.

    (3) Within 3,000 flight cycles after the effective date of this AD, replace the rivets that attach the pressurized floor panel to gantries 4 and 5 with new titanium alloy bolts in accordance with the applicable service bulletin. Accomplishment of this replacement constitutes terminating action for the repetitive inspections.

    (b) If any discrepant or broken rivet is detected during any inspection specified in paragraph (a)(2) of this AD, prior to further flight, accomplish either paragraph (b)(1) or (b)(2) of this AD, as applicable, in accordance with Airbus Service Bulletin A300- 53-0331, dated March 18, 1997 (for Airbus Model A300 series airplanes); or Airbus Service Bulletin A300-53-6107, dated March 18, 1997 (for Airbus Model A300-600 series airplanes).

    (1) If less than 15 discrepant or broken rivets are detected, prior to further flight, replace the discrepant or broken rivets with serviceable rivets and continue the repetitive inspections, in accordance with the applicable service bulletin, until

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    accomplishment of the action required by paragraph (a)(3) of this AD.

    (2) If 15 or more discrepant or broken rivets are detected, prior to further flight, replace all the rivets that attach the pressurized floor panel to gantries 4 and 5 with new titanium alloy bolts, in accordance with the applicable service bulletin. Accomplishment of this replacement constitutes terminating action for the repetitive inspections required by this AD.

    (c) 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.

    (d) 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 97-176-229(B), dated August 13, 1997.

    Issued in Renton, Washington, on December 2, 1998. John W. McGraw, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

    [FR Doc. 98-32620Filed12-8-98; 8:45 am]

    BILLING CODE 4910-13-U

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