Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG Dart 528, 529, 532, 535, 542, and 555 Series Turboprop Engines

The FAA is adopting a new airworthiness directive (AD) for Rolls-Royce Deutschland Ltd & Co KG (RRD) Dart 528, 529, 532, 535, 542, and 555 series turboprop engines. This AD requires a dimensional inspection of the intermediate pressure turbine (IPT) disk or an ultrasonic inspection of the seal arm contact between the high pressure turbine (HPT) and the IPT disk seal arm and rework or replacement of the IPT disk if wear outside acceptable limits is found. This AD results from reports of a number of HPT disk failures, some of which resulted in portions of the HPT disk being released. We are issuing this AD to prevent HPT disk failure, which can result in an uncontained engine failure and damage to the airplane.