LONDON - Aerospace engineer Rolls-Royce said it had burned through 3 billion pounds ($3.8 billion) in its first half as the hours flown by its engines halved due to the COVID-19 pandemic.

The British company, which makes engines for the Boeing 787 and Airbus 350, said it expected to see an improvement in the second half, resulting in free cash outflow for the full year of about 4 billion pounds.

It said restructuring, which will see at least 9,000 jobs cut, would support a recovery that would produce a free cash inflow of at least 750 million pounds in 2022.

"The COVID-19 pandemic has created a historic shock in civil aviation which will take several years to recover," CEO Warren East said.

The outflow reflected a 1.1 billion pound fall in receipts from engine flying hours and deliveries and a 1.1 billion pound one-off impact from the end of invoice factoring, a practice used to align the timing of cash receipts with deliveries.

The company said it had increased its liquidity to 8.1 billion pounds, including a new undrawn 2 billion pound five-year term-loan facility.

($1 = 0.7911 pounds)

(Reporting by Paul Sandle; editing by Edmund Blair and Jason Neely) ((paul.sandle@thomsonreuters.com; +44 20 7542 6843; Reuters Messaging: paul.sandle.thomsonreuters.com@reuters.net))