Rolls Royce is considering a plan to close its jet engine plants for civil aircraft for two weeks in a bid to stem losses. The engineering giant has suffered a drop in sales with fewer jets in the air requiring servicing. The plans are tentative as the company aims to thrash out an agreement with unions. The plan, first disclosed by the Sunday Telegraph, will not affect its defence or energy divisions. “As part of the agreement reached with the union last summer we agreed in principle to enter into negotiations about delivering a 10% productivity and efficiency improvement across our Civil Aerospace operations in the UK,” Rolls Royce said in a statement.