2005-02-03: Turbine (LPT) Blades 3rd and 4th Stage

2005-02-03 Pratt & Whitney: Amendment 39-13948. Docket No. 98-ANE-80-AD. Supersedes AD 99-27-01, Amendment 39-11482. Effective Date (a) This AD becomes effective March 3, 2005. Affected ADs (b) This AD supersedes AD 99-27-01. Applicability (c) This AD applies to Pratt & Whitney (PW) JT8D-209, -217, -217A, -217C, and -219 series turbofan engines. These engines are installed on, but not limited to, Boeing 727 series and McDonnell Douglas MD-80 series airplanes. Unsafe Condition (d) This AD results from reports of 194 blade fractures since 1991, with 37 of those blade fractures resulting in low pressure turbine (LPT) case separation, and three reports of uncontained 3rd stage and 4th stage LPT blade failures with cowl penetration. We are issuing this AD to prevent an uncontained blade failure that could result in damage to the airplane. Compliance (e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done. Initial Torque Inspection for JT8D-209, -217, and -217A Engines (f) For JT8D-209, -217, and -217A engines, perform the initial torque inspection of 3rd and 4th stage LPT blades for shroud notch wear. Use the procedures described in Accomplishment Instructions, part 1, paragraphs 1. through 3. of PW Alert Service Bulletin (ASB) No. JT8D A6224, Revision 5, dated June 11, 2004, at the applicable threshold in the following Table 1: Table 1.-Initial Torque Inspection Threshold for JT8D-209, -217, and -217A Engines Blade type Hours time-in-service (TIS) Inspection threshold (1) New pre-Service Bulletin (SB) No. 5867 (small notch) 3rd stage turbine blades. Any number Within 6,000 hours TIS. (2) Refurbished pre-SB No. 5867 (small notch) 3rd stage turbine blades. (i) Fewer than 3,000 (ii) 3,000 or more Within 4,000 hours TIS. Within 6,000 hours TIS, or within 1,000 hours TIS after the effective dateof this AD, whichever occurs first. (3) New post-SB No. 5867 (large notch) 3rd stage turbine blades. . Any number Within 10,000 hours TIS. (4) Refurbished post-SB No. 5867 (large notch) 3rd stage turbine blades. (i) Fewer than 6,000 (ii) 6,000 or more Within 7,000 hours TIS. Within 8,000 hours TIS, or within 1,000 hours TIS after the effective date of this AD, whichever occurs first. (5) New pre-SB No. 6029 (small notch) 4th stage turbine blades. Any number Within 6,000 hours TIS. (6) Refurbished pre-SB No. 6029 (small notch) 4th stage turbine blades. (i) Fewer than 3,000 (ii) 3,000 or more Within 4,000 hours TIS. Within 6,000 hours TIS, or within 1,000 hours TIS after the effective date of this AD, whichever occurs first. (7) New post-SB No. 6029 or new post-SB No. 6308 (large notch) 4th stage turbine blades. Any number Within 10,000 hours TIS (8) Refurbished post-SB No. 6029 or refurbished post-SB No. 6308 (large notch) 4th stage turbine blades. (i) Fewer than 6,000 (ii) 6,000 or more Within 7,000 hours TIS. Within 8,000 hours TIS, or within 1,000 hours TIS after the effective date of this AD, whichever occurs first. Repetitive Torque Inspections for JT8D-209, -217, and -217A Engines (g) For JT8D-209, -217, and -217A engines, perform repetitive torque inspections of 3rd and 4th stage LPT blades for shroud notch wear. Use the procedures described in Accomplishment Instructions, Part 1, Paragraph 1. of PW ASB No. JT8D A6224, Revision 5, dated June 11, 2004, at the applicable intervals in the following Table 2 and Table 3: Table 2.-3rd Stage Repetitive Torque Inspection Intervals for JT8D-209, -217, and -217A Engines Inspection torque readings Number of readings Disposition Greater than or equal to 15 LB-IN (1.695 N.m) All Repeat torque inspection within 1,000 hours TIS since last inspection. Less than 15 LB-IN (1.695 N.m) but greater than or equal to 10 LB-IN (1.130 N.m). One or more Repeat torque inspection within 500 hours TIS since last inspection. Less than 10 LB-IN (1.130 N.m) but greater than or equal to 5 LB-IN (0.565 N.m). One to three Repeat torque inspection within 125 hours TIS since last inspection. Less than 10 LB-IN (1.130 N.m) but greater than or equal to 5 LB-IN (0.565 N.m). Four or more Remove engine from service within 20 hours TIS since last inspection. Less than 5 LB-IN (0.565 N.m) One or more Remove engine from service within 20 hours TIS since last inspection. Table 3.-4th Stage Repetitive Torque Inspection Intervals for JT8D-209, -217, and -217A Engines Inspection torque readings Number of readings Disposition Greater than or equal to 15 LB-IN (1.695 N.m) All Repeat torque inspection within 1,000 hours TIS since last inspection. Less than 15 LB-IN (1.695 N.m) but greater than or equal to 10 LB-IN (1.130 N.m). One or more Repeat torque inspection within 500 hours TIS since last inspection. Less than 10 LB-IN (1.130 N.m) but greaterthan or equal to 5 LB-IN (0.565 N.m). One to six Repeat torque inspection within 125 hours TIS since last inspection. Less than 10 LB-IN (1.130 N.m) but greater than or equal to 5 LB-IN (0.565 N.m). Seven or more Remove engine from service within 20 hours TIS since last inspection. Less than 5 LB-IN (0.565 N.m) One or more Remove engine from service within 20 hours TIS since last inspection. (h) Subsequent repeat inspection intervals must not exceed the previous inspection interval. JT8D-209, -217, and -217A Engines Removed From Service (i) JT8D-209, -217, and -217A engines removed from service may be returned to service after a detailed inspection and repair or replacement for all blades, of the failed stage, that exceed Engine Manual limits is done. Information on repairing or replacing turbine blades can be found in Sections 72-53-12 through 72-53-13 of the JT8D-200 Engine Manual, Part No. 773128. Initial Inspection for JT8D-217C and -219 Engines (j) For JT8D-217C and -219 engines, perform the initial torque inspection of 4th stage LPT blades for shroud notch wear. Use the procedures described in Accomplishment Instructions, Part 2, Paragraphs 1. through 3. of PW ASB No. JT8D A6224, Revision 5, dated June 11, 2004, at the applicable threshold in the following Table 4: Table 4.-Initial Torque Inspection Threshold for JT8D-217C and -219 Engines Blade Type TIS Inspection threshold (1) New pre-SB No. 6090 (small notch) 4th stage turbine blades. Any number Within 5,000 hours TIS. (2) Refurbished pre-SB No. 6090 (small notch) 4th stage turbine blades. (i) Fewer than 3,000 (ii) 3,000 or more Within 4,000 hours TIS. Within 5,000 hours TIS, or within 1,000 hours TIS after the effective date of this AD, whichever occurs first. (3) New post-SB No. 6090, new post-SB No. 6402, or new post-SB No. 6412 (large notch) 4th stage turbine blades. Any number Within 10,000 hours TIS. (4) Refurbished As-Cast post-SB No.6090, post-SB No. 6402, or post-SB No. 6412 (large notch) 4th stage turbine blades. Any number Within 7,000 hours TIS. (5) Refurbished Modified post-SB No. 6090, post-SB No. 6402, or post-SB No. 6412 (large notch) 4th stage turbine blades. (i) Fewer than 3,000 (ii) 3,000 or more Within 4,000 hours TIS. Within 7,000 hours TIS, or within 1,000 hours TIS after the effective date of this AD, whichever occurs first. Repetitive Torque Inspections for JT8D-217C and -219 Engines (k) For JT8D-217C and -219 engines, perform repetitive torque inspections of 4th stage LPT blades for shroud notch wear. Use the procedures described in Accomplishment Instructions, Part 2, Paragraph 1. of PW ASB No. JT8D A6224, Revision 5, dated June 11, 2004, at the applicable intervals in the following Table 5: Table 5.-Repetitive Torque Inspection Intervals for JT8D-217C and -219 Engines Inspection torque readings Number of readings Disposition Greater than or equal to 15LB-IN (1.695 N.m) All Repeat torque inspection within 1,000 hours TIS since last inspection. Less than 15 LB-IN (1.695 N.m) but greater than or equal to 10 LB-IN (1.130 N.m). One or more Repeat torque inspection within 500 hours TIS since last inspection. Less than 10 LB-IN (1.130 N.m) but greater than or equal to 5 LB-IN (0.565 N.m). One to six Repeat torque inspection within 125 hours TIS since last inspection. Less than 10 LB-IN (1.130 N.m) but greater than or equal to 5 LB-IN (0.565 N.m). Seven or more Remove engine from service within 20 hours TIS since last inspection. Less than 5 LB-IN (0.565 N.m). One or more Remove engine from service within 20 hours TIS since last inspection. (l) Subsequent repeat inspection intervals must not exceed the previous inspection interval. JT8D-217C and -219 Engines Removed From Service (m) JT8D-217C and -219 engines removed from service may be returned to service after a detailed inspection and repair or replacement for all blades, of the failed stage, that exceed Engine Manual limits is done. Information on repairing or replacing turbine blades can be found in Sections 72-53-12 through 72-53-13 of the JT8D-200 Engine Manual, Part No. 773128. Other Criteria for All Engine Models Listed in This AD (n) Whenever a refurbished or used blade is intermixed with new blades in a rotor, use the lowest initial inspection threshold that is applicable. (o) The initial torque inspection or the repetitive inspection intervals for a particular stage may not be reset unless the blades for that stage are refurbished or replaced. (p) Whenever a used (service run) blade is reinstalled in a rotor, the previous used time should be subtracted from the initial torque inspection threshold. LPT-to-Exhaust Case Bolts and Nuts Replacement (q) At next accessibility to the LPT-to-exhaust case bolts, part number (P/N) ST1315-15, and nuts, P/N 4023466, replace bolts and nuts with bolts and nutsmade of Tinidur material. Information on replacing the bolts and nuts can be found in PW SB No. 6455, dated January 15, 2004. Definitions (r) For the purpose of this AD, refurbishment is defined as restoration of either the shrouds or blade retwist or both, per the JT8D-200 Engine Manual, Part No. 773128. (s) For the purpose of this AD, "As-Cast" refers to blades that were machined from new castings and "Modified" refers to blades that were derived from the pre-SB No. 6090 configuration. (t) For the purpose of this AD, "accessibility to the LPT-to-exhaust case bolts" refers to when the engine is disassembled sufficiently to give access to the LPT-to-exhaust case bolts, which is whenever the inner turbine fan ducts are removed. Alternative Methods of Compliance (u) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19. Material Incorporated by Reference (v) You must use Pratt & Whitney (PW) Alert Service Bulletin (ASB) No. JT8D A6224, Revision 5, dated June 11, 2004, to perform the inspections required by this AD. The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You can get a copy from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-8770, fax (860) 565-4503. You can review copies at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Related Information (w) None.