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/6 Malfunction of Bleed Valve Mechanism Featuring Mod. 5866 - Operational and Maintenance Action 11/82 Applicability: Rolls Royce Spey 555-15, 15H, 15N and 15P engines featuring MOD. 5866 (SB SP72-916). Requirement: Rolls Royce Spey Alert SB No. SP72-A963. Compliance: Forthwith. Background: There have recently been reports of engines featuring Bleed Valve Mechanism MOD. 5866 showing an unacceptable rise in T.G.T. at low power conditions in the following cases:- 1. Immediately on throttle advance from a low power setting where HP RPM stagnates, particularly following engine deceleration. B. Less frequently - during steady state running at low power settings. This AD is issued to alert flight and maintenance crews of the possibility of this condition occurring and precautions which should be taken.