The company, however, stuck to its guidance for the full year of achieving an underlying profit and free cash flow of £700m, plus or minus £100m. Rolls Royce was producing the Trent 900 for the superjumbo.
United Kingdom enginemaker Rolls-Royce on Tuesday expressed confidence over plans for Britain's departure from the European Union, but revealed that the pound's Brexit-fuelled slump has left it languishing in the red.
The engineering giant, who have a UK Civil Nuclear base in Gloucester, reported that underlying group revenue rose by 7 per cent to £7.353billion in the six months to June 30. There were presently 50 engines in its inventory compared to the usual number of around 15.
The company, however, warned that its Trent 1000 engine in-service costs will rise by about 100 million pounds across the next three years.
It delivered 257 large civil aerospace engines in the half, it said, and said it made good progress in reducing average large engine unit losses, down by 200,000 pounds to 1.3 million pounds.
Rolls' turnaround has been hampered by problems with its Trent 1000 engines, which has caused airlines to ground Boeing 787s while repairs are carried out.
Rolls-Royce has spent £100 million ($121 million, 109 million euros) to prepare for Britain's European Union exit.
Warren East, chief executive, forecast a much better second half as trading picks up in civil aerospace and power systems.
The Derby-headquartered company, in a statement to the London Stock Exchange, also said that it had made good progress on fixing problems with its Trent 1000 engines, although customer disruption remained. It takes the total hit from the move to £245 million.
The group, which employs several hundred people at the Advanced Manufacturing Park in Rotherham, where it produces single-crystal turbine blades reported statutory interim pre-tax losses of £791 million against £1.2 billion a year ago.