AD FAA-2019-0056

We are superseding airworthiness directive (AD) 2017-22-13 for certain Rolls-Royce plc (RR) RB211-Trent 900 turbofan engine models. AD 2017-22-13 required an inspection of the drains mast and the replacement or repair of the drains mast if a crack is found. This AD retains this requirement, but adds repetitive inspections and expands the population of affected RR RB211-Trent 900 turbofan engine models. This AD was prompted by RR in-service findings that indicated a need to include part number (P/N) FW29847 drains mast and additional RR RB211- Trent 900 turbofan engines to the affected population. We are issuing this AD to address the unsafe condition on these products.