The manufacturer has long been investigating serious issues with the compressors in its Trent 1000 units.
In June, the British firm established the fault was present in two batches of its engines.
Its half year results, issued on Thursday (June 2), reveal the company has set aside a further £550 million for the works this year., taking the total projected cost to nearly £1.5 billion.
Major Trent 1000 customers include Boeing, who use the engines on its 787 jet aircraft.
