COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Rolls Royce Turbine Engines - Spey Series AD/RRT-S/14 LPT Stage 2 NGV Seal Support 10/99 Applicability: Rolls Royce Spey 555-15, -15/10, -15H,.-15H/10, -15N, -15N/12, .-15N/20, -15P, -15P/12, and -15P/20 engines. Requirement: Modify affected LPT Stage 2 NGV Seal Supports by incorporating Modification No 6421 in accordance with Rolls Royce Service Bulletin Sp72-1063. Note: CAA (UK) AD 007-05-99 also refers. Compliance: No later than 30 June 2003. This Airworthiness Directive becomes effective on 7 October 1999. Background: Heavy rubbing can occur between the LP turbine stage 2 nozzle guide vane support ring seal assembly and the LP turbine discs seals. In extreme cases the disc drive arms can be damaged.