Rolls-Royce Holdings (RR.L), the world’s second largest maker of aero engines, said Chief Executive John Rishton would retire in July, and be succeeded by Warren East, the former leader of Britain’s biggest listed technology company ARM (ARM.L). East, who has been a non-executive director of Rolls-Royce since January 2014, was chief executive of ARM between 2001 and 2013, and oversaw the growth of the Cambridge-based firm into a leading developer of chips for companies like Apple (AAPL.O).