[Federal Register Volume 60, Number 34 (Tuesday, February 21, 1995)] [Proposed Rules] [Pages 9645-9647] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 95-4122] ======================================================================= ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. 94-NM-120-AD] Airworthiness Directives; Boeing Model 747SP 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proposed airworthiness directive (AD), applicable to certain Boeing Model 747SP series airplanes, that would have superseded an existing AD to require inspections to detect cracks in the web of the wing front spar, and modification, if necessary. That proposal was prompted by a report of cracking in the web in an area outside the inspection zone specified in the existing AD. A crack in the web that is not detected before it extends outside the chord footprints can allow fuel leakage. This action revises the proposed rule by reducing the compliance time for inspections of certain airplanes. The actions specified by this proposed AD are intended to prevent fuel leakage onto an engine and a resultant fire due to cracking in the web of the wing front spar. DATES: Comments must be received by March 7, 1995. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 94-NM-120-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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. 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, Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-2776; fax (206) 227-1181. 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 94-NM-120-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. 94-NM-120-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 Boeing Model 747SP series airplanes, was published as a notice of proposed rulemaking (NPRM) in the Federal Register on October 28, 1994 (59 FR 54134). That NPRM would have superseded an existing AD to require repetitive inspections to detect cracks in the web of the wing front spar over engine numbers 2 and 3, and repair, if necessary. That NPRM was prompted by a report of cracking in the web in an area outside the inspection zone specified in the existing AD. That condition, if not corrected, could result in fuel leakage onto an engine and a resultant fire. [[Page 9646]] Two commenters support the proposed rule. One commenter to the NPRM, Boeing, requests that the proposed compliance time of 1,000 landings, specified in paragraph (b) of the NPRM for airplanes on which the terminating modification has not been accomplished, be shortened to 6 months, as recommended in the manufacturer's service bulletin. The FAA concurs with the commenter's request. Due to an error during publication of the NPRM, an incorrect compliance time was specified in paragraph (b). The FAA's intent was that this compliance time coincide with the recommendation of the manufacturer's service bulletin. Paragraph (b) of this supplemental NPRM has been revised to specify a compliance time of ``prior to the accumulation of 4,000 total landings on the airplane, or within 6 months after the effective date of the AD, whichever occurs later.'' Since this change expands 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. The FAA has recently reviewed the figures it has used over the past several years in calculating the economic impact of AD activity. In order to account for various inflationary costs in the airline industry, the FAA has determined that it is necessary to increase the labor rate used in these calculations from $55 per work hour to $60 per work hour. The economic impact information, below, has been revised to reflect this increase in the specified hourly labor rate. As a result of recent communications with the Air Transport Association (ATA) of America, the FAA has learned that, in general, some operators may misunderstand the legal effect of AD's on airplanes that are identified in the applicability provision of the AD, but that have been altered or repaired in the area addressed by the AD. The FAA points out that all airplanes identified in the applicability provision of an AD are legally subject to the AD. If an airplane has been altered or repaired in the affected area in such a way as to affect compliance with the AD, the owner or operator is required to obtain FAA approval for an alternative method of compliance with the AD, in accordance with the paragraph of each AD that provides for such approvals. A note has been included in this supplemental NPRM to clarify this requirement. The manufacturer has advised that it is currently developing a modification program for the engine struts on these airplanes that will positively address the fatigue cracking condition and other items associated with the engine struts. Once this modification program is developed and approved, the FAA may consider additional rulemaking. There are approximately 35 Model 747SP series airplanes of the affected design in the worldwide fleet. The FAA estimates that 11 airplanes of U.S. registry would be affected by this proposed AD. The FAA estimates that it would take approximately 22 work hours per airplane to accomplish the proposed inspections (between front spar stations 628 and 675) specified in this AD, and that the average labor rate is $60 per work hour. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $14,520, or $1,320 per airplane. The total cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. Should an operator elect to accomplish the terminating modification that would be provided by this AD action, it would take approximately 644 work hours to accomplish it, at an average labor rate of $60 per work hour. The cost of required parts would be $21,800. Based on these figures, the total cost impact of the terminating modification would be $60,440 per airplane. 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. Sec. 39.13 [Amended] 2. Section 39.13 is amended by removing amendment 39-6702 (55 FR 33279, August 15, 1990), and by adding a new airworthiness directive (AD) to read as follows: Boeing: Docket 94-NM-120-AD. Applicability: Model 747SP series airplanes; variable numbers RG001 through RG142 inclusive, and RG171 through RG222 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 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 use the authority provided in paragraph (f) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD. Compliance: Required as indicated, unless accomplished previously. To prevent fuel leakage onto an engine and a resultant fire, accomplish the following: (a) For airplanes on which the ``terminating modification'' [between front spar station (FSS) 640 and FSS 670] specified in Boeing Alert Service Bulletin 747-57A2259, dated February 15, 1990; or Revision 1, dated September 6, 1990; has not been accomplished: Within the next six months after September 21, 1990 (the effective date of AD 90-17-18, amendment 39-6702), perform a visual and an ultrasonic inspection of the front spar web between front spar station (FSS) 636 and FSS 675 in accordance with Boeing Alert Service Bulletin 747- [[Page 9647]] 57A2259, dated February 15, 1990, or Revision 1, dated September 6, 1990. If no crack is found, repeat these inspections at intervals not to exceed 1,000 landings until the inspections required by paragraph (b) of this AD are accomplished. (b) For airplanes on which the ``terminating modification'' [between front spar station (FSS) 640 and FSS 670] specified in Boeing Alert Service Bulletin 747-57A2259, dated February 15, 1990; or Revision 1, dated September 6, 1990; has not been accomplished: Prior to the accumulation of 4,000 total landings on the airplane, or within 6 months after the effective date of this AD, whichever occurs later, perform the inspections specified in paragraphs (b)(1), (b)(2), and (b)(3) of this AD to detect cracks in the web between FSS 628 and FSS 675, in accordance with Boeing Alert Service Bulletin 747-57A2259, Revision 2, dated June 9, 1994. Accomplishment of these inspections terminates the repetitive inspection requirement of paragraph (a) of this AD. If no crack is found, repeat these inspections thereafter at intervals not to exceed 1,000 landings. (1) Perform an ultrasonic inspection in the web under the upper and lower chord footprints; and (2) Perform a high frequency eddy current inspection in the web in an area one inch below the upper chord and one inch above the lower chord footprints; and (3) Perform a detailed visual inspection in the forward face of the web of the wing front spar at fastener locations in the web-to- stiffeners and web-to-rib posts. (c) For airplanes on which the ``terminating modification'' specified in Boeing Alert Service Bulletin 747-57A2259, dated February 15, 1990; or Revision 1, dated September 6, 1990; has been accomplished: Prior to the accumulation of 4,000 total landings on the airplane, or within 6 months after the effective date of this AD, whichever occurs later, perform the inspections specified in paragraphs (c)(1), (c)(2), and (c)(3) of this AD to detect cracks in the web between FSS 628 and FSS 636, in accordance with Boeing Alert Service Bulletin 747-57A2259, Revision 2, dated June 9, 1994. If no crack is found, repeat these inspections thereafter at intervals not to exceed 1,000 landings. (1) Perform an ultrasonic inspection of the web under the upper and lower chord footprints; and (2) Perform a high frequency eddy current inspection of the web in an area one inch below the upper chord and one inch above the lower chord footprints; and (3) Perform a detailed visual inspection of the forward face of the web of the wing front spar at fastener locations in the web-to- stiffeners and web-to-rib posts. (d) If any crack is found during any inspection required by this AD, prior to further flight, accomplish a terminating modification (between FSS 623 and FSS 670) in accordance with Boeing Alert Service Bulletin 747-57A2259, Revision 2, dated June 9, 1994; or in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. (e) Installation of a terminating modification (between FSS 623 and FSS 670) in accordance with Boeing Alert Service Bulletin 747- 57A2259, Revision 2, dated June 9, 1994; or in accordance with a method approved by the Manager, Seattle ACO; 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, Seattle ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. (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 February 14, 1995. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 95-4122 Filed 2-17-95; 8:45 am] BILLING CODE 4910-13-U