Summary
The FAA proposes to supersede an existing airworthiness directive (AD) for Rolls-Royce (RR) RB211-535E4 series turbofan engines. That AD currently requires initial and repetitive inspections of the outer combustion case for cracks and possible removal. This proposed AD would require the same inspections, but would require using RR Mandatory Service Bulletin (MSB) RB.211-72-7775, Revision 3, dated April 9, 1999. This proposed AD results from RR issuing a revision to the MSB. We are proposing this AD to prevent an uncontained outer combustion case burst, which could result in damage to the airplane.