Summary
We propose to adopt a new airworthiness directive (AD) for certain Pratt & Whitney Canada Corp. (P&WC) turboprop engines. This proposed AD was prompted by in-service events involving the perforation of engine cases as a result of the liberation of power turbine (PT) blades and the fracture/displacement of the PT containment ring. This proposed AD would require installing a reinforcement liner to the PT containment ring and, for certain PT containment rings, adding scallops. We are proposing this AD to prevent uncontained engine failure and damage to the airplane.