Airworthiness Directive · Amendment 39-16753 · General Electric Company GE90-76B; GE90-77B; GE90-85B; GE90-90B; and GE90-94B Turbofan Engines
General Electric Company GE90-76B; GE90-77B; GE90-85B; GE90-90B; and GE90-94B Turbofan Engines
This AD applies to General Electric Company GE90-76B; GE90-77B; GE90-85B; GE90-90B; and GE90-94B turbofan engines with a high-pressure compressor rotor (HPCR) 8-10 stage spool, part number (P/N) 1844M90G01 or 1844M90G02, installed.
We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires initial and repetitive fluorescent penetrant inspections (FPIs) and eddy current inspections (ECIs) of the high-pressure compressor rotor (HPCR) 8-10 stage spool, part numbers (P/Ns) 1844M90G01 and 1844M90G02, for cracks between the 9-10 stages at each piece-part exposure. This AD was prompted by cracks discovered on one HPCR 8-10 spool between the 9-10 stages in the weld joint. We are issuing this AD to prevent failure of the HPCR 8-10 stage spool, uncontained engine failure, and damage to the airplane.
Comply with this AD within the compliance times specified, unless already done.
(f)(1) At the next piece-part exposure of the HPCR 8-10 stage spool after the effective date of this AD, perform a fluorescent penetrant inspection (FPI) and eddy current inspection (ECI) of the weld joint between the 9-10 stages of the HPCR 8-10 stage spool for cracks.
(2) Thereafter, perform repetitive FPIs and ECIs of the weld joint between the 9-10 stages of the HPCR 8-10 stage spool for cracks at every piece-part exposure of the HPCR 8-10 stage spool.
(3) Remove from service any HPCR 8-10 stage spool found cracked.
(4) Guidance on performing the FPI can be found in GE90 (GEK100700) Engine Manual, Chapter 72-31-08, Inspection 001.
(5) Guidance on performing the ECI can be found in GE90 (GEK100700) Engine Manual, Chapter 72-31-08, Special Procedures 001.
For the purpose of this AD, piece-part exposure is when the HPCR stage 8-10 spool is removed from the engine and completely disassembled.
