Summary
We propose to supersede airworthiness directive (AD) 2016-03- 03 that applies to all Rolls-Royce plc (RR) Viper Mk. 521, Viper Mk. 522, and Viper Mk. 601-22 turbojet engines. AD 2016-03-03 requires reducing the life of certain critical parts. Since we issued AD 2016- 03-03, RR determined that additional parts for these RR Viper engine models are affected. This proposed AD would add additional engine parts to the applicability. We are proposing this AD to address the unsafe condition on these products.