The Chief Executive Officer (CEO) of Malaysia Airlines Christoph Mueller has resigned after less than a year of trying to turn around the struggling airline's image and fortunes. Malaysia Airlines suffered losses after its plane MH370 went missing and its plane MH17 was shot down over eastern Ukraine in 2014, killing 537 people.

Mueller said, according to BBC, that he was leaving the company due to “changing personal circumstance.” Mueller will continue in his post until September this year and will stay on the board as a non-executive director. He had joined Malaysia Airlines last May to oversee a $1.56 billion turnaround plan that involved massive job cuts and shedding of unprofitable destinations.

The company’s chairman, Md Nor Yusof, said, according to BBC: “We are very disappointed to lose Christoph as CEO but we fully understand his reasons and respect his need to do this.” The company also reportedly said that it is on the lookout for a new CEO from both internal and external candidates.

Before Malaysia Airlines, Mueller, known in the industry as a turnaround expert, was CEO at Irish carrier Aer Lingus Group PLC. A report Tuesday by the Wall Street Journal also said that under Mueller’s leadership, Malaysia Airlines was reconstituted with a new corporate entity and he laid off almost one-third of its 18,000 workforce. The company also reportedly renegotiated previous supplies contracts that were considered expensive.

Mueller's other significant contributions included his role in getting new planes on lease and signing a code-share deal with Emirates Airline, which is connected to European and U.S. cities, a move that was expected to help boost passenger numbers, the Journal reported.

According to a report by Time magazine, Mueller also reinvented the carrier as a much smaller regional airline that could compete with budget airlines like Air Asia. The company plans to sell off larger planes like the double-decker Airbus A380, the report said. Earlier this year, Malaysia Airlines also ended its service between Kuala Lumpur and Amsterdam, the route on that MH17 was flying when it was shot down by a surface-to-air missile.

“While we would have wanted Mr. Mueller to continue as planned, we also respect and ultimately agree to his decision to leave ahead of the end of his three-year contract, due to a change in his personal circumstances,” Khazanah, Malaysia’s sovereign-wealth fund, said, according to the Journal, adding: “We note that Mr. Mueller has laid the groundwork, put in place a strong management team, and undertaken the necessary measures and initiatives that have produced encouraging signs of progress on Malaysia Airlines’ path to recovery.”

Mueller had recently said that the company was on its way to return to profitability but still had a long way to go till it regained the trust of passengers after the air disasters.