[Federal Register Volume 62, Number 48 (Wednesday, March 12, 1997)] [Proposed Rules] [Pages 11388-11390] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 97-6085] ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION 14 CFR Part 39 [Docket No. 95-NM-216-AD] RIN 2120-AA64 Airworthiness Directives; Airbus Model A320 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SUMMARY: This document revises an earlier proposed airworthiness directive (AD), which would have superseded an existing AD that is applicable to certain Airbus Model A320 series airplanes. The existing AD currently requires inspections to detect cracking of certain floor beams and side box-beams, and repair of cracks. It also requires modification of the pressure floor. The previously proposed action would have added a requirement to install a new, improved modification for the pressure floor. This action revises the previously proposed rule by adding a one-time inspection to verify proper clearance between the fasteners of the reinforcement bracket and the bellcrank of the free-fall extension system of the main landing gear (MLG) and its associated tie rod attachment nut. It also would require that a different new, improved modification be installed. The actions specified by this proposed AD are intended to prevent reduced structural integrity of the fuselage, restricted operation of the MLG free-fall system and, consequently, reduced ability to use the MLG during an emergency. DATES: Comments must be received by March 31, 1997. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 95-NM-216-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: Tim Backman, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-2797; fax (206) 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 95-NM-216-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-103, Attention: Rules Docket No. 95-NM-216-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Discussion A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to add an airworthiness directive (AD), applicable to certain Airbus Model A320 series airplanes, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on April 15, 1996 (61 FR 16414). That NPRM would have superseded AD 93-14-04, amendment 39-8628 (58 FR 39440, July 23, 1993), to continue to require a one-time eddy current and detailed visual inspections to detect cracks of various areas around the fastener/bolt holes of the pressure floor. That NPRM also would have added a requirement to install a new, improved modification requirement for the pressure floor at section 15 of the fuselage. That NPRM was prompted by the results of a full-scale fatigue test, which indicated that fatigue cracking can occur in those areas. Such fatigue cracking, if not detected and corrected in a timely manner, could result in reduced structural integrity of the fuselage. Actions Since Issuance of Originally Proposed NPRM Since the issuance of that NPRM, the Direction G\n\rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an additional unsafe condition may exist on Airbus Model A320 series airplanes that were modified in accordance with Airbus Service Bulletin A320-53-1023, Revision 3, dated March 18, 1994. That modification was considered to be terminating action for the repetitive inspection requirements of AD 93-14-04. The DGAC advises that, following accomplishment of the subject modification, it received reports indicating that interference could occur between the fasteners of the reinforcement bracket and the bellcrank of the free-fall extension system of the main landing gear (MLG) and its associated tie rod attachment nut. This condition, if not corrected, could restrict operation of the free-fall system of the MLG and, consequently, result in reduced ability to use the MLG during an emergency. [[Page 11389]] Description of Revised Service Information Airbus has issued Revision 7 of Service Bulletin A320-53-1023, dated November 3, 1995, which describes procedures for installation of a new, improved modification of the pressure floor at section 15 of the fuselage. This revision differs from Revision 3 of the service bulletin in the following two aspects: 1. It includes updated installation procedures for the fasteners located adjacent to the bell crank lever of the free-fall extension system of the MLG; and 2. It includes additional procedures for reworking the attachment bracket located above the pressure diaphragm. Accomplishment of this modification would eliminate the need for the one-time eddy current and detailed visual inspections. Installation of the new, improved modification will positively address the unsafe condition identified as reduced structural integrity of the fuselage, and restricted operation of the MLG free fall system. Airbus also has issued All Operators Telex (AOT) 53-08, Revision 01, dated January 15, 1996, which concerns only certain airplanes. The service bulletin describes procedures for performing a one-time inspection to verify proper clearance between the fasteners of the reinforcement bracket and the bellcrank of the free-fall extension system of the MLG and its associated tie rod attachment nut. The AOT also describes procedures for reinstalling the reinforcement bracket fasteners, or, under certain conditions, reworking the bellcrank lever and fasteners, if necessary. The DGAC classified the Airbus service bulletin and AOT as mandatory and issued French airworthiness directive 96-053-077(B), dated March 13, 1996, in order to assure the continued airworthiness of these airplanes in France. Explanation of Changes Made to Proposal Based on this new information, the FAA has determined that the previously issued proposal must be revised in order to adequately address the unsafe condition presented by interference problems associated with accomplishment of the procedures contained in Airbus Service Bulletin A320-53-1023, up to and including Revision 6, dated September 4, 1995. Accordingly, the FAA has added a new paragraph (c) to this supplemental NPRM, which would require the accomplishment of the procedures specified in Airbus AOT 53-08, Revision 01, dated January 15, 1996, described previously. In addition, paragraph (c) of the supplemental NPRM also would include a requirement to accomplish the modification specified in Revision 7 of Airbus Service Bulletin A320- 53-1023, described previously. The FAA also has revised paragraph (c) of the originally-proposed NPRM [designated as paragraph (d) in this supplemental NPRM] to reference Revision 7 of Airbus Service Bulletin A320-53-1023 as the appropriate source of service information for modification of the pressure floor. 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 There are approximately 24 Airbus Model A320 series airplanes of U.S. registry that would be affected by this proposed AD. The inspections that are currently required by AD 93-14-04 take approximately 37 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required inspections on U.S. operators is estimated to be $53,280, or $2,220 per airplane. The new inspection that is proposed by this AD action would take approximately 11 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the new inspection on U.S. operators is estimated to be $15,840, or $660 per airplane. The new modification that is proposed by this AD action would take approximately 142 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will be supplied by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the modification on U.S. operators is estimated to be $204,480, or $8,520 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. 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 removing amendment 39-8628 (58 FR 39440, July 23, 1993), and by adding a new airworthiness directive (AD) to read as follows: Airbus Industrie: Docket 95-NM-216-AD. Supersedes AD 93-14-04, amendment 39-8628. Applicability: Model A320 series airplanes, manufacturer's serial numbers 002 through 008 inclusive, 010 through 078 inclusive, and 080 through 107 inclusive; 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 [[Page 11390]] owner/operator must request approval for an alternative method of compliance in accordance with paragraph (f) 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, restricted operation of the main landing gear (MLG) free-fall system, and, consequently, reduced ability to use the MLG during an emergency, accomplish the following: (a) Prior to the accumulation of 12,000 total landings, or within 6 months after August 23, 1993 (the effective date of AD 93- 14-04, amendment 39-8628), whichever occurs later, accomplish the requirements of paragraphs (a)(1) and (a)(2) of this AD, in accordance with Airbus Industrie Service Bulletin A320-53-1024, dated September 23, 1992, or Revision 1, dated March 31, 1994. As of the effective date of this new AD, only Revision 1 of this service bulletin shall be used. (1) Conduct an eddy current inspection to detect cracking around the fastener/bolt holes at the top horizontal flange of the floor beams and side box-beams, at the two sides of the pressure floor, and at the vertical integral stiffener of the side box-beams; and (2) Conduct a detailed visual inspection to detect cracking around the fastener/bolt holes at the fillet radius and riveted area of the top outboard flange of the side box-beam, and at the flange- corner radius of the slanted inboard flange of the side box-beam and fittings. (b) If any crack is detected during the inspections required by paragraph (a) of this AD, prior to further flight, repair the crack in accordance with a method approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. (c) For airplanes on which the modification specified in Airbus Service Bulletin A320-53-1023, dated September 23, 1992, as amended by Service Bulletin Change Notice 0A, dated January 20, 1993; Revision 1, dated March 23, 1993; Revision 2, dated October 22, 1993; Revision 3, dated March 18, 1994; Revision 4, dated September 30, 1994; Revision 5, dated February 28, 1995; or Revision 6, dated September 4, 1995; has been accomplished: Accomplish paragraphs (c)(1) and (c)(2) of this AD. (1) Prior to the accumulation of 1,000 landings after the effective date of this AD, perform a one-time inspection to verify proper clearance between the fasteners of the reinforcement bracket and the bellcrank of the free-fall extension system of the MLG and its associated tie rod attachment nut, in accordance with Airbus All Operators Telex (AOT) 53-08, Revision 01, dated January 15, 1996. (i) If the minimum clearance is greater than 3 mm (0.118 inch) and no evidence of interference is detected, within 60 months following accomplishment of the inspection required by paragraph (c)(1) of this AD, reinstall the reinforcement bracket fasteners in accordance with Airbus Service Bulletin A320-53-1023, Revision 7, dated November 3, 1995. (ii) If the minimum clearance is 3 mm (0.118 inch) or less, and no evidence of interference is detected, within 18 months following accomplishment of the inspection required by paragraph (c)(1) of this AD, reinstall the reinforcement bracket fasteners in accordance with Airbus Service Bulletin A320-53-1023, Revision 7, dated November 3, 1995. (iii) If any interference is detected, prior to further flight, accomplish either paragraph (c)(1)(iii)(A) or (c)(1)(iii)(B) of this AD. (A) Reinstall the reinforcement bracket fasteners in accordance with Airbus Service Bulletin A320-53-1023, Revision 7, dated November 3, 1995; or (B) Rework the bellcrank lever and fasteners in accordance with Airbus AOT 53-08, Revision 01, dated January 15, 1996. Within 60 months following accomplishment of the rework, reinstall the reinforcement bracket fasteners in accordance with Airbus Service Bulletin A320-53-1023, Revision 7, dated November 3, 1995. (2) Prior to the accumulation of 24,000 total landings, or 6 months after the effective date of this AD, whichever occurs later, modify the pressure floor at section 15 of the fuselage in accordance with Airbus Service Bulletin A320-53-1023, Revision 7, dated November 3, 1995. Accomplishment of the modification terminates the requirements of this AD. (d) For airplanes on which the modification specified in Airbus Service Bulletin A320-53-1023, dated September 23, 1992, as amended by Service Bulletin Change Notice 0A, dated January 20, 1993; Revision 1, dated March 23, 1993; Revision 2, dated October 22, 1993; Revision 3, dated March 18, 1994; Revision 4, dated September 30, 1994; Revision 5, dated February 28, 1995; or Revision 6, dated September 4, 1995; has not been accomplished: Prior to the accumulation of 18,000 total landings, or within 6 months after the effective date of this AD, whichever occurs later, modify the pressure floor at section 15 of the fuselage in accordance with Airbus Service Bulletin A320-53-1023, Revision 7, dated November 3, 1995. Accomplishment of the modification terminates the requirements of this AD. (e) Accomplishment of the modification of the pressure floor at section 15 of the fuselage in accordance with Airbus Service Bulletin A320-53-1023, Revision 7, dated November 3, 1995, constitutes terminating action for the requirements of this AD. (f) 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, Standardization Branch, ANM-113. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Standardization Branch, ANM-113. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113. (g) 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. Issued in Renton, Washington, on March 5, 1997. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 97-6085 Filed 3-11-97; 8:45 am] BILLING CODE 4910-13-U