Airworthiness Directives; Rolls-Royce plc Model RB211 Turbofan Engines

This amendment revises an existing airworthiness directive (AD) that is applicable to Rolls-Royce plc (RR) model RB211-535E4-37, RB211-535E4-B-37, and RB211-535E4-B-75 turbofan engines. The existing AD will become effective on June 20, 2003, and requires removal from service of certain high pressure (HP) turbine discs before they reach newly established life limits. This amendment requires the same actions, but removes the model RB211-535E4-37 turbofan engine from the applicability. This revision to the existing AD is prompted by further data gathering by the FAA that demonstrates that the model RB211-535E4- 37 turbofan engine is not affected by machining-induced cracking within the currently published life of the HP turbine disc. The actions specified in this AD are intended to prevent machining-induced cracking of the HP turbine disc which could cause an uncontained HP turbine disc failure and damage to the airplane.