Action
Final rule.
Summary
We are superseding airworthiness directive (AD) AD 2012-04-13, for all Rolls-Royce plc (RR) model RB211 Trent 553-61, 553A2-61, 556- 61, 556A2-61, 556B-61, 556B2-61, 560-61, and 560A2-61; and RB211 Trent 768-60, 772-60, and 772B-60; and RB211-Trent 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17; and RB211-524G2-T-19, -524G3-T- 19, -524H-T-36, and -524H2-T-19 turbofan engines that have a high- pressure (HP) compressor stage 1 to 4 rotor disc installed, with a certain part number (P/N) installed. AD 2012-04-13 required repetitive inspections of the axial dovetail slots and follow-on corrective action depending on findings. This new AD expands the population of affected parts. This AD also changes, for the purposes of this AD, the definition of "engine shop visit." This AD was prompted by reports of additional affected HP compressor rotor discs that require the same action. We are issuing this AD to detect cracks in the HP compressor stage 1 and 2 disc posts, which could result in failure of the disc post and HP compressor blades, damage to the engine, and damage to the airplane.