Summary
We propose to revise airworthiness directive (AD) 2010-17- 11R1, which applies to all Dowty Propellers R408/6-123-F/17 model propellers. AD 2010-17-11R1 requires initial and repetitive application of sealant between the bus bar assembly and the backplate assembly of certain line-replaceable units (LRUs). That AD also provides an optional terminating action to the repetitive re-application of sealant. This proposed AD would increase the interval allowed between the required re-application of sealant, and would specify an additional acceptable sealant. We are proposing this AD to prevent an in-flight double generator failure, which could result in reduced control of the airplane.