Airworthiness Directives; Dowty Aerospace Propellers Model R381/6-123-F/5 Propellers

This amendment revises an existing airworthiness directive (AD) that is applicable to Dowty Aerospace Propellers Model R381/6-123- F/5 propellers, that requires initial and repetitive visual and ultrasonic inspections of propeller blades for cracks across the camber face, and, if blades are found cracked, replacement with serviceable blades. This amendment is prompted by an engineering analysis of field service data and certification testing that indicate that the repetitive visual inspection interval can be safely increased and that the ultrasonic inspections can be eliminated. The actions specified in this proposed AD are intended to detect propeller blade cracks and propagation, which if not detected could result in propeller blade separation and possible aircraft loss of control.