Airworthiness Directives; Rolls-Royce plc RB211 Series Turbofan Engines

The FAA is adopting a new airworthiness directive (AD) for Rolls-Royce plc (RR) RB211-22B series, RB211-524B, -524C2, -524D4, - 524G2, -524G3, and -524H series, and RB211-535C and -535E series turbofan engines with high pressure compressor (HPC) stage 3 disc assemblies, part numbers (P/Ns) LK46210, LK58278, LK67634, LK76036, UL11706, UL15358, UL22577, UL22578, and UL24738 installed. This AD allows disc assemblies not modified by a certain RR service bulletin to reach their full life only after the disc assemblies are modified with anti-corrosion protection. This AD results from the manufacturer's reassessment of the corrosion risk on HPC stage 3 disc assemblies that have not yet been modified with sufficient application of anti- corrosion protection. We are issuing this AD to prevent corrosion- induced uncontained disc failure, resulting in damage to the airplane.