Summary
The FAA proposes to supersede an existing airworthiness directive (AD) for Rolls-Royce Deutschland Ltd & Co KG (RRD) (formerly Rolls-Royce Deutschland GmbH, formerly BMW Rolls-Royce GmbH) models BR700-710A1-10 and BR700-710A2-20 turbofan engines. That AD currently requires initial and repetitive visual and ultrasonic inspections of fan discs, part numbers (P/Ns) BRR18803, BRR19248, and BRR20791 for cracks, and if necessary, replacement with serviceable parts. This proposed AD would require the same inspections of these fan discs, with certain old design P/N fan blades installed. This proposed AD would extend the inspection interval for certain fan discs having new design P/N fan blades installed. Also, this proposed AD would add as optional terminating action to the repetitive inspections, installation of certain P/N new fan discs, certain P/N new fan blades, and engine fan speed (N1) Keep Out Zone software. This proposed AD results from a revised RRD service bulletin (SB) that introduces relaxed inspection intervals for certain P/N combinations of fan discs and fan blades, and introduces improved design fan discs and fan blades. We are proposing this AD to detect and prevent cracks in the fan disc that could result in an uncontained engine failure and damage to the airplane.