Airworthiness Directives; Dowty Propellers Propellers

We are revising an existing airworthiness directive (AD) that applies to all Dowty Propellers R408/6-123-F/17 model propellers. That AD currently requires initial applications of sealant between the bus bar assembly and the backplate assembly of certain line-replaceable units, and repetitive applications of sealant on all R408/6-123-F/17 model propellers. This new AD requires the same actions and allows the use of an equivalent sealant as prescribed in revised service information. This AD was prompted by the need to add an optional terminating action to the applications of sealant. We are issuing this AD to prevent an in-flight double generator failure, which could result in reduced control of the airplane.