AD 2011-25-08 Airworthiness Directives; International Aero Engines Turbofan Engines

This AD applies to International Aero Engines (IAE) V2500-A1, V2522-A5, V2524-A5, V2525-D5, V2527-A5, V2527E-A5, V2527M-A5, V2528-D5, V2530-A5, and V2533-A5 turbofan engines.

(1) Perform 360 degree borescope inspections of the HPT stage 1 blade outer air seal segments for evidence of the distress conditions listed in Appendix D of IAE SB No. V2500-ENG-72-0580, Revision 3, dated August 23, 2011. (2) For V2525-D5 and V2528-D5 turbofan engines: (i) Inspect within 1,000 operating hours after the engine meets all criteria as defined in Table 1 of this AD, or within 600 operating hours after the effective date of this AD, whichever is greater. (ii) Thereafter, re-inspect within every 1,000 operating hours or as defined in Appendix D of IAE SB No. V2500-ENG-72-0580, Revision 3, dated August 23, 2011, whichever is less. (iii) Use Accomplishment Instructions paragraphs 3.B.(1) through 3.B.(3), and Appendices A through D of IAE SB No. V2500-ENG-72-0580, Revision 3, dated August 23, 2011, to do these inspections. (3) For V2500-A1, V2522-A5, V2524-A5, V2527-A5, V2527E-A5, V2527M-A5, V2530-A5, and V2533-A5 turbofan engines: (i) Inspect within 1,200 operating hours after the engine meets all criteria as defined in Table 1 of this AD, or within 600 operating hours after the effective date of this AD, whichever is greater. (ii) Thereafter, re-inspect within every 1,200 operating hours or as defined in Appendix D of IAE SB No. V2500-ENG-72-0580, Revision 3, dated August 23, 2011, whichever is less. (iii) Use Accomplishment Instructions paragraphs 3.A.(1) through 3.A.(3), and Appendices A through D of IAE SB No. V2500-ENG-72-0580, Revision 3, dated August 23, 2011, to do these inspections. Table 1—Stage 1 Blade Outer Air Seal Segment Inspection Compliance Criteria Engine model Stage 1 blade outer air seal segments hours-since-new or since-last-repair (greater than) Stage 1 blade outer air seal segments cycles-since-new or since-last-repair (greater than) Exhaust gas temperature margin degrees Celsius (less than) A1 6,000 3,800 45 A5 6,000 3,500 45 D5 5,000 3,500 45 (4) Exhaust Gas Temperature Margin is defined as the expected margin during a sea-level takeoff on a 30-degree Celsius Outside Air Temperature Day. Guidance on how to calculate EGT margin can be found in IAE SIL 057. EGT margin smoothed data (data averaged over 6 consecutive flights) is to be compared with the criteria in Table 1. If a gap in EGT data exists due to temporary loss of data, you may use linear interpolation. Calculate operating hours from the point when all criteria exceed the requirements in Table 1. (5) Except as provided below, the inspection of paragraphs (f)(2)(i) through (f)(2)(iii) and (f)(3)(i) through (f)(3)(iii) must be performed after all the criteria in Table 1 are satisfied; regardless of subsequent EGT margin calculations or engine rating changes. Temporary EGT margin excursions below the criteria in Table 1 that are corrected with simple troubleshooting methods ( e.g., LRU (line replaceable unit) replacement or correction of a measurement error) do not constitute satisfying the criteria in Table 1.

(1) As terminating action to the repetitive 360 degree borescope inspections required in paragraphs (f)(2)(ii) and (f)(3)(ii) above, install improved durability stage 1 blade outer air seal segments at the next HPT module subassembly exposure, which is defined as separation of the HPT module mating flanges. (i) For V2500-A1 turbofan engines, use paragraphs 1.B., Concurrent Requirements, and paragraphs 3.(1)(a), 3.(1)(b)(iii), and 3.(2)(a) of the Accomplishment Instructions of IAE SB No. V2500-ENG-72-0542, Revision 1, dated January 7, 2009, to do the installation. (ii) For V2522-A5, V2524-A5, V2525-D5, V2527-A5, V2527E-A5, V2527M-A5, V2528-D5, V2530-A5, and V2533-A5 turbofan engines, use paragraphs 1.B., Concurrent Requirements, and paragraphs 3.(1)(a), 3.(1)(b), 3.(1)(c)(ii), and 3.(2)(a) of the Accomplishment Instructions of IAE SB No. V2500-ENG-72-0483, Revision 3, dated January 7, 2009, to do the installation. (iii) Both IAE SBs No. V2500-ENG-72-0542, Revision 1, and SB No. V2500-ENG-72-0483, Revision 3, require modification of the stage 1 HPT support assembly before installing the new blade outer air seal segments. You must complete the modification using those SBs, as applicable to the appropriate engine model, to properly perform the mandatory terminating action of this AD.

(1) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done. (2) For engines that have incorporated IAE Service Bulletin (SB) No. V2500-ENG-72-0483, Revision 3 or earlier, or IAE SB No. V2500-ENG-72-0542, Revision 1 or earlier, no further action is required.

None.