Summary
The FAA proposes to adopt a new airworthiness directive (AD) for Rolls-Royce Deutschland Ltd & Co KG (formerly Rolls-Royce plc) (RRD) Dart 528, 529, 532, 535, 542, and 552 series turbofan engines. This proposed AD would require repetitive inspections of high pressure turbine (HPT) blade platforms and shrouds, and reworking the engines if the inspections reveal excessive gaps between blade shrouds. This proposed AD results from reports of HPT disk rim failures. We are proposing this AD to prevent HPT disk rim failures resulting in the release of portions of the HPT disk, uncontained engine failure, and damage to the airplane.