AD 95-03-03 60 FR 11615

This amendment adopts a new airworthiness directive (AD) that is applicable to Hartzell Propeller Inc. Model HC-B4TN-3/ T10173F(N)(B,K)-12.5 and HC-B4TN-3A/T10173F(N)(B,K)-12.5 propellers installed on Beech A100 and A100A aircraft. This action requires an initial and repetitive inspections, and specified rework or retirement, as necessary, of the propeller hub assemblies and propeller blades. This amendment is prompted by a determination that the current hub design and blade repair limits do not adequately protect against initiation of fatigue cracks in the propeller hub arm bore and do not prevent the resonant speed of the propeller from shifting into the permitted ground idle operating range. The actions specified in this AD are intended to prevent initiation of fatigue cracks in the propeller hub arm bore and subsequent progression to failure, with departure of the hub arm and blade, that may result in loss of aircraft control.