Airworthiness Directives; Honeywell International Inc. (Formerly AlliedSignal Inc. and Garrett Turbine Engine Company) TPE331-11U, -12B, -12JR, -12UA, -12UAR, and -12UHR Series Turboprop Engines

This amendment adopts a new airworthiness directive (AD) that is applicable to Honeywell International Inc. (formerly AlliedSignal Inc. and Garrett Turbine Engine Company) TPE331-11U, -12B, -12JR, - 12UA, -12UAR, and -12UHR series turboprop engines. This action requires repetitive Spectrometric Oil Analysis Program (SOAP) sampling, SOAP trend assessment, and inspections and replacement of certain gearbox components. This amendment is prompted by reports of spur gearshaft (bull gear) rim separations and high-speed pinion (HSP) assembly failures. The actions specified in this AD are intended to prevent bull gear rim separations and HSP assembly failures from abnormal gear wear, which could result in uncontained gearbox fragmentation, in-flight shutdowns, and engine rotor overspeed events.