Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain General Electric Company (GE) GE90-76B, GE90-85B, GE90-90B, and GE90-94B model turbofan engines. This proposed AD was prompted by a commanded in-flight shutdown (IFSD) due to cracking and rockback of the high-pressure turbine (HPT) stage 2 nozzles resulting in blade liberation, severe rotor imbalance, and liberation of the exhaust centerbody. This proposed AD would require initial and repetitive borescope inspections (BSIs) of the forward platforms of the HPT stage 2 blades or the leading edges of the HPT stage 2 nozzles and, depending on the results of the inspections, removal and replacement of the HPT stage 2 nozzles with a part eligible for installation. As a mandatory terminating action to the repetitive BSIs of the forward platforms of the HPT stage 2 blades or the leading edges of the HPT stage 2 nozzles, this proposed AD would require replacement of the HPT stage 2 nozzles. The FAA is proposing this AD to address the unsafe condition on these products.