Airworthiness Directives; Honeywell International Inc. TFE731-4, -4R, -5, -5AR, -5BR, and -5R Series Turbofan Engines

The FAA is adopting a new airworthiness directive (AD) for Honeywell International Inc. TFE731-4, -4R, -5, -5AR, -5BR, and -5R series turbofan engines, with interstage turbine transition (ITT) duct, part number (P/N) 3075292-1; 3075292-3; 3074766-1; 3077063-1; 3075655- 1; 3075655-2; 3075699-1; or 3075699-3, installed. This AD requires replacing the affected ITT duct with a serviceable and redesigned ITT duct. This AD results from reports of 49 low-pressure turbine (LPT) blade separation events. Six of those events resulted in circumferential failure of the LPT2 or LPT3 nozzle assembly, leading to deformation of the ITT duct and uncontainment of the turbine blades and fragments of the LPT nozzle assembly. We are issuing this AD to prevent uncontainment of turbine blades and fragments of the LPT nozzle assembly, which could result in damage to the airplane.