EASA AD No.: 2010-0008R1 on Trent 900:
...Wear, beyond Engine Manual limits, has been identified on the abutment
faces of the splines on the Trent 900 Intermediate Pressure (IP) shaft rigid
coupling on several engines during strip....
...Rearward movement of the IP turbine would enable contact with static
turbine components and would result in loss of engine performance with
potential for in-flight shut down, oil migration and oil fire below the LP
turbine discs prior to sufficient indication resulting in loss of LP turbine disc
integrity....
http://ad.easa.europa.eu/blob/easa_a..._2010-0008R1_2