[Federal Register Volume 59, Number 18 (Thursday, January 27, 1994)] [Unknown Section] [Page 0] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 94-1762] [[Page Unknown]] [Federal Register: January 27, 1994] ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION 14 CFR Part 39 [Docket No. 93-ANE-81] Airworthiness Directives; Pratt & Whitney JT8D Series Turbofan Engines AGENCY: Federal Aviation Administration, DOT. ACTION: Notice of proposed rulemaking (NPRM). ----------------------------------------------------------------------- SUMMARY: This document proposes to supersede telegraphic airworthiness directive (AD) T89-05-52 by adopting a new AD, applicable to Pratt & Whitney (PW) JT8D series turbofan engines. Telegraphic AD T89-05-52 currently requires repetitive ultrasonic inspections of a combustion chamber outer case (CCOC) weld, but also allows visual inspection or fluorescent magnetic penetrant inspection (FMPI) of certain CCOC's under specified conditions. This proposal would allow ultrasonic inspections only. This proposal is prompted by the greater availability of ultrasonic inspection equipment, which provides a more definitive means of discovering cracks than either visual inspections or FMPI. The actions specified by the proposed AD are intended to prevent rupture of the CCOC, which could result in fire, engine cowl release, or aircraft damage. DATES: Comments must be received by March 28, 1994. ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 93-ANE-81, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may be inspected at this location between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays. The service information referenced in the proposed rule may be obtained from Pratt & Whitney, 400 Main St, East Hartford, CT 06108. This information may be examined at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA. FOR FURTHER INFORMATION CONTACT: Mark A. Rumizen, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (617) 238-7137, fax (617) 238-7199. 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 should 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 93-ANE-81.'' 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, New England Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 93-ANE-81, 12 New England Executive Park, Burlington, MA 01803-5299. Discussion On March 1, 1989, the Federal Aviation Administration (FAA) issued telegraphic airworthiness directive (AD) T89-05-52, applicable to Pratt & Whitney (PW) JT8D series turbofan engines, which requires repetitive ultrasonic inspections for cracks in the combustion chamber outer case (CCOC). In addition, that telegraphic AD allowed operators who did not have ultrasonic inspection capability to perform visual inspections and fluorescent magnetic penetrant inspections (FMPI) of CCOC's. That action was prompted by reports of two CCOC's, both part number (P/N) 796761, which were found in service with severe cracking and distress at the weld which joins the forward case detail to the rear flange detail. These cracks initiated from an area of incomplete weld created during the manufacturing process and were not detected during the final inspection process. Another CCOC, P/N 806675, is manufactured using a similar process and has the same potential for incomplete welds, but to date have not been found cracked. That condition, if not corrected, could result in rupture of the CCOC, which could result in fire, engine cowl release, or aircraft damage. Since the issuance of that telegraphic AD, the FAA has received reports that most operators now have the capability to perform ultrasonic inspections, which provides a more definitive means of discovering cracks than either visual inspections or FMPI. In telegraphic AD T89-05-52, reinspection of all CCOC's is required, including reinspection of those CCOC's that exhibited minimal ultrasonic indications during initial inspection. The FAA has determined analytically that CCOC's that exhibit maximum signal amplitudes of less than 40 percent are not life limited at the defined weld area. Therefore, CCOC's that meet this signal criteria for two consecutive ultrasonic inspections may be marked with a new P/N, provided the second ultrasonic inspection is accomplished at least 2,500 cycles in service (CIS) after the first inspection and the second inspection is performed in accordance with Appendix C of PW Alert Service Bulletin (ASB) No. 5842, Revision 3, dated October 10, 1990. Finally, the FAA has determined that certain CCOC's, P/N 806675, were ultrasonically inspected by PW during the manufacturing process, and therefore do not need to be inspected again until they are accessible in the shop. The FAA has reviewed and approved the technical contents of PW ASB No. 5842, Revision 3, dated October 10, 1990, that describes procedures for repetitive ultrasonic inspections of CCOC's for cracks. Since an unsafe condition has been identified that is likely to exist or develop on other engines of this same type design, the proposed AD would supersede telegraphic AD T89-05-52 to require repetitive ultrasonic inspections of CCOC's for cracks. The proposed AD would also allow CCOC's that meet certain signal criteria for two consecutive ultrasonic inspections to be marked with a new P/N. Once remarked, those CCOC's would not need to meet the repetitive ultrasonic inspection requirements of this AD. Finally, the proposed AD would require ultrasonic inspections on certain CCOC's, P/N 806675, identified by serial number, that were ultrasonically inspected by PW during the manufacturing process, when they are accessible in the shop. The actions are required to be accomplished in accordance with the service bulletin described previously. The FAA estimates that 1,000 engines installed on aircraft of U.S. registry would be affected by this proposed AD, that it would take approximately 2 work hours per engine to accomplish the proposed actions, and that the average labor rate is $55 per work hour. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $110,000. 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 14 CFR part 39 of the Federal Aviation Regulations 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 adding the following new airworthiness directive: Pratt & Whitney: Docket No. 93-ANE-81. Applicability: Pratt & Whitney (PW) Models JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR turbofan engines, with combustion chamber outer case (CCOC), Part Number (P/N) 796761 or 806675. These engines are installed on but not limited to Boeing 727 and 737 series, and McDonnell Douglas DC-9 series aircraft. Compliance: Required as indicated, unless accomplished previously. To prevent rupture of the CCOC, which could result in fire, engine cowl release, or aircraft damage, accomplish the following: (a) Except for CCOC's cited in paragraph (c) of this airworthiness directive (AD), ultrasonically inspect CCOC's installed in engines for cracks within 10 days or 75 cycles in service (CIS) after the effective date of this AD, whichever occurs later, in accordance with paragraph 2.A.(3) and Appendix B of PW Alert Service Bulletin (ASB) No. 5842, Revision 3, dated October 10, 1990. (b) For CCOC's not installed in engines and not cited in paragraph (c) of this AD, ultrasonically inspect CCOC's for cracks prior to returning the CCOC's to service in accordance with paragraph 2.A.(5) and Appendix C of PW ASB No. 5842, Revision 3, dated October 10, 1990. (c) For CCOC's, P/N 806675, listed by serial number in Table 1 and paragraph 2.A.(10) of PW ASB No. 5842, Revision 3, dated October 10, 1990, accomplish the following: (1) At the next removal of the CCOC from the engine after the effective date of this AD, ultrasonically inspect CCOC's for cracks in accordance with paragraph 2.A.(5) and Appendix C of PW ASB No. 5842, Revision 3, dated October 10, 1990. (2) Remove from service or reinspect CCOC's in accordance with paragraphs (d) and (e), respectively, of this AD. (3) Mark CCOC's with new part numbers in accordance with paragraphs 2.A.(5)(c) and 2.A.(11) of PW ASB No. 5842, Revision 3, dated October 10, 1990, that: (i) Have accumulated at least 2,500 CIS since new; and (ii) Exhibit a maximum ultrasonic signal amplitude of less than 40% during the inspection conducted subsequent to 2,500 CIS since new. (d) Remove from service and replace with a serviceable part CCOC's with maximum ultrasonic signal amplitude determined as follows: (1) CCOC's with greater than or equal to 360%, prior to further flight, with no ferry flight permitted in accordance with paragraph (i) of this AD below. (2) CCOC's with less than 360%, but greater than or equal to 240%, prior to further flight, with ferry flight permitted, in accordance with paragraph (i) of this AD below. (e) Thereafter, ultrasonically inspect CCOC's, P/N's 796761 and 806675, for cracks at intervals determined by maximum ultrasonic signal amplitude, in accordance with paragraph 2.A. and Appendix B of PW ASB No. 5842, Revision 3, dated October 10, 1990, for installed CCOC's; or paragraph 2.A.(5) and Appendix C of PW ASB No. 5842, Revision 3, dated October 10, 1990, for uninstalled CCOC's; as applicable, as follows: (1) For those CCOC's that meet the criteria described in paragraph (d) of this AD, remove from service and replace with a serviceable part. (2) For those CCOC's with less than 240%, but greater than or equal to 100%, at intervals of 1,000 CIS since last inspection. (3) For those CCOC's with less than 100%, but greater than or equal to 40%, at intervals of 2,500 CIS since last inspection. (4) For those CCOC's with less than 40%, inspect at the next removal of the CCOC from the engine since last inspection. (f) Mark CCOC's with new P/N's, in accordance with paragraphs 2.A.(5)(c) and 2.A.(11) of PW ASB No. 5842, Revision 3, dated October 10, 1990, that meet the following criteria: (1) At least two consecutive ultrasonic inspections have been performed on the CCOC; and (2) the second inspection was performed in accordance with paragraph (b) of this AD; and (3) have accumulated at least 2,500 CIS since the first ultrasonic inspection; and (4) that exhibit a maximum ultrasonic signal amplitude of less than 40% in both inspections. (g) Remarking of CCOC's with a new P/N in accordance with paragraph (f) of this AD constitutes terminating action to the inspection requirements of this AD. (h) 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, Engine Certification Office. The request should be forwarded through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office. Note: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office. (i) Except for aircraft with engines having CCOC's that must be removed from service in accordance with paragraph (d)(1) of this AD, special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the aircraft to a location where the requirements of this AD can be accomplished. Issued in Burlington, Massachusetts, on January 20, 1994. Mark C. Fulmer, Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service. [FR Doc. 94-1762 Filed 1-26-94; 8:45 am] BILLING CODE 4910-13-P