Airworthiness Directives; [Hoffmann Propeller GmbH & Co KG Models HO-V343 and HO-V343K Propellers]

The FAA is superseding an existing airworthiness directive (AD) for Hoffmann Propeller GmbH & Co KG Models HO-V343 and HO-V343K propellers. That AD currently requires initial and repetitive visual inspections of propeller blades for blade shake and blade nut preload. That AD also requires initial and repetitive eddy current inspections of blade hubs for damage and cracks. This AD requires an ultrasonic inspection of the propeller hub and an eddy current inspection of the propeller hub if any cracks are discovered during ultrasonic inspection. Additionally, this AD requires sending a hub inspection report to the manufacturer. This AD also requires replacement of the propeller if any signs of blade shake, cracks, or other damage to the propeller hub outside serviceable limits are detected during the inspections. This AD results from the discovery of a propeller blade separation due to a possible hub failure. We are issuing this AD to prevent propeller hub failure and blade separation due to an unknown root cause, leading to damage and possible loss of control of the airplane.