Airworthiness Directives; Dowty Propellers R175/4-30-4/13; R175/4-30-4/13e; R184/4-30-4/50; R193/4-30-4/50; R193/4-30-4/61; R193/4-30-4/64; R193/4-30-4/65; R193/4-30-4/66; R.209/4-40-4.5/2; R212/4-30-4/22; R.245/4-40-4.5/13; R257/4-30-4/60; and R.259/4-40-4.5/17 Model Propellers

The FAA is superseding an existing airworthiness directive (AD) for the Dowty Propellers, propeller models listed above. That AD currently requires, for all Dowty Rotol propellers, visual inspections for seizure and for cadmium plating of the blade pitch change operating links and eyebolt fork assemblies. That AD also requires replacement or heat-treatment of the blade pitch change operating links and eyebolt fork assemblies, if necessary. This AD requires the same actions, but only for certain propeller models. This AD results from the FAA determining that AD 70-16-02 does not apply to all propellers, since current Dowty propellers are differently designed. We are issuing this AD supersedure to specify the affected propeller models, and to prevent seizure or embrittlement and cracking of the blade pitch change operating links and eyebolt fork assemblies, which could result in reduced controllability of the airplane.