Malaysia Airlines CEO and managing director Christoph Mueller will step down in September, according to the carrier's sole shareholder, Khazanah Nasional Berhad. Mueller's three-year contract began in May 2015, but he's leaving "due to a change in his personal circumstances," according to Khazanah. The company plans to announce a CEO prior to Mueller's departure, and he will stay on as a nonexecutive director to assist with the transition. Mueller has been working on the carrier's recovery plan following the loss of two jetliners in 2014.