Action
Final rule.
Summary
We are superseding airworthiness directive (AD) 2012-26-14 for all Rolls-Royce Deutschland Ltd & Co KG (RRD) BR700-715A1-30, BR700- 715B1-30, and BR700-715C1-30 turbofan engines. AD 2012-26-14 required removal from service of certain high-pressure (HP) compressor stages 1 to 6 rotor disc assemblies before exceeding certain thresholds. This AD requires removal from service at those same thresholds but restricts the applicability to engines exposed to silver-plated nuts, and removes the terminating action statement required by AD 2012-26-14. This AD was prompted by RRD development of a new silver-free nut that, if installed with a new HP compressor stages 1 to 6 rotor disc assembly, would correct the unsafe condition identified in AD 2012-26-14. We are issuing this AD to prevent failure of the HP compressor stages 1 to 6 rotor disc assembly, which could lead to an uncontained engine failure and damage to the airplane.