Summary
We propose to adopt a new airworthiness directive (AD) for certain Rolls-Royce Deutschland Ltd & Co KG (RRD) models Tay 620-15 and Tay 650-15 turbofan engines. This proposed AD was prompted by RRD recalculating the Declared Safe Cyclic Life (DSCL) for certain low- pressure compressor (LPC) rotor disc assemblies operating to the Plan D Flight Mission. This proposed AD would require removing the affected LPC rotor disc assemblies at a new lower recalculated DSCL. We are proposing this AD to prevent failure of the LPC rotor disc assembly, uncontained engine failure, and damage to the airplane.