Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to revise an existing airworthiness directive (AD) that applies to all Dowty Propellers R408/6-123-F/17 model propellers. The existing AD currently requires initial applications of sealant between the bus bar assembly and the backplate assembly of certain line-replaceable units (LRUs), and repetitive applications of sealant on all R408/6-123-F/17 model propellers. Since we issued that AD, Dowty Propellers has introduced an optional terminating action to the applications of sealant. This proposed AD would add the optional terminating action. We are proposing this AD to prevent an in-flight double generator failure, which could result in reduced controllability of the airplane.