Turbine Section

1 FAA Aviation Safety SPECIAL AIRWORTHINESS INFORMATION BULLETIN SUBJ: Turbine Section SAIB: NE-15-19 Date: July 14, 2015 This is information only. Recommendations aren’t mandatory.

Introduction This Special Airworthiness Information Bulletin (SAIB) alerts you, owners, operators, and certified repair facilities of airplanes equipped with certain Pratt & Whitney Division (PW) PW4000 series turbofan engines to potential low pressure turbine (LPT) 4th stage vane crack due to a non- conforming fillet radius in a high stress area. Affected engines are PW4052(-3); PW4056(-3); PW4060(-3); PW4062(-3); PW4062A(-3); PW4152(-3); PW4156A(-3); PW4158(-3); PW4460(-3); PW4462(-3) with LPT 4th stage vane cluster assembly, part number (P/N) 51N674-01, and PW4164; PW4164-1D; PW4168; PW4168A; PW4168-1D; PW4168A-1D; PW4170 with LPT 4th Stage Vane Cluster Assembly, P/N 51N774-01 or P/N 52N774-01. At this time, the airworthiness concern is not an unsafe condition that would warrant airworthiness directive action under Title 14 of the Code of Federal Regulations (14 CFR) part 39. Background We have received reports of LPT 4th stage vane liberations, which have resulted in multiple engine failures and one low-energy case uncontainment on PW4000 series engines. All failures resulted in safe landings. Investigations revealed some 4th stage vane clusters manufactured between May 1992 and February 1999, from certain casting die, have a non-conforming vane outer diameter shroud pressure side fillet radius in a high stress area. This SAIB provides information on LPT 4th stage vane fractures and lists service information intended to prevent further occurrences of vane fracture and possible engine failure. PW Service Bulletins (SBs) No. PW4ENG 72-804 and PW4G-100-72-251 were issued to specify inspection of 4th stage vane cluster assemblies when the subassembly is disassembled. Recommendation The FAA recommends that you follow the instructions in PW SBs No. PW4ENG 72-804 and PW4G- 100-72-251 to inspect and remove the affected parts. For Further Information Contact Katheryn Malatek, Aerospace Engineer, ANE-142, 12 New England Executive Park, Burlington, Massachusetts, 01803; phone: (781) 238-7747; fax: (781) 238-7199; e-mail: [email protected]. For Related Service Information Contact Pratt & Whitney Division, United Technologies Corporation, 400 Main St., East Hartford, Connecticut, 06108; phone: (860) 565-0140; e-mail: [email protected]