Summary
We propose to revise airworthiness directive (AD) 2008-21-07 that applies to certain Dowty Propellers model R408/6-123-F/17 propellers. AD 2008-21-07 requires initial and repetitive inspections of the blade bonded metallic leading edge (L/E) guards for correct bonding until they accumulate more than 1,200 flight hours (FH) time in service. Since we issued AD 2008-21-07, Dowty Propellers has introduced updated service bulletins that identify terminating action to the requirements of AD 2008-21-07. This proposed AD would maintain the inspection and replacement requirements of AD 2008-21-07, provide an optional terminating action to those requirements, and add a new part number to the list of affected parts. We are proposing this AD to prevent the loss of the bonded metallic L/E guard of the propeller, which could result in damage to the propeller or to the airplane, or injury to personnel.