Airworthiness Directives; Hamilton Standard 14RF Series, 14SF Series, and Hamilton Standard/British Aerospace Model 6/5500/F Propellers

This amendment supersedes an existing airworthiness directive (AD), applicable to Hamilton Standard 14RF series, 14SF series, and Hamilton Standard/British Aerospace 6/5500/F series propellers, that currently requires a one-time ultrasonic shear wave inspection for cracks in the propeller blade taper bore. This amendment requires initial and repetitive ultrasonic shear wave inspections, and a one- time visual and borescope inspection of the taper bore for corrosion as a terminating action to the ultrasonic shear wave inspections. This amendment is prompted by reports of two incidents where a portion of the propeller blade was lost in flight. The actions specified by this AD are intended to prevent loss of a propeller blade due to cracks initiating in the blade taper bore, that can result in possible aircraft damage, and possible loss of aircraft control.