Summary
This document proposes to revise an existing airworthiness directive (AD) that is applicable to Dowty Aerospace Propellers Model R381/6-123-F/5 propellers. That action currently 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 proposed revision would increase the time-in-service (TIS) intervals between required visual and ultrasonic inspections. This proposal is prompted by an engineering analysis of field service data and certification testing that indicate that the repetitive inspection interval can be safely increased. The actions specified in this proposed revision are intended to prevent propeller blade cracks and propagation, which could result in propeller blade separation and possible aircraft loss of control.