Summary
We propose to supersede an existing airworthiness directive (AD) that applies to 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. The existing AD requires repetitive inspections of the axial dovetail slots, and follow-on corrective action depending on findings. This proposed AD expands the population of affected parts. This proposed AD also changes, for the purposes of this AD, the definition of ``engine shop visit.'' We are proposing 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.