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.
Agency Contact: Frank Walsh, Aerospace Engineer, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (617) 238-7158, fax (617) 238-7199.
This rule is final. Its effective date is March 23, 1995.