LONDON, Feb 29 (Reuters) - Emirates Airlines will not buy Rolls-Royce's Trent XWB-97 jet engines until it is convinced that they are durable, Emirates President Tim Clark said on Thursday.

After previous concerns from Clark, Rolls-Royce had said last year that it was taking steps to improve the durability of the engines. (Reporting by Joanna Plucinska, writing by Muvija M; Editing by Sachin Ravikumar)