Malaysia Airlines CEO quit Tuesday to take a job at Ryanair, a fresh blow to the troubled Malaysian carrier which is still struggling to recover from twin disasters in 2014.
Peter Bellew has been appointed chief operations officer at the Irish airline, where he used to work, following a recent crisis that led to the cancellation of thousands of flights.
He was the third chief executive of Malaysia Airlines since 2014, when the company was plunged into crisis by the disappearance of flight MH370 and the downing of MH17 over Ukraine.
A statement from Ryanair to the London Stock Exchange said that Bellew's new role would focus on the work of pilots to ensure the "rostering failure which Ryanair suffered in early September will never be repeated".
A pilot shortage was at the root of the recent crisis at Ryanair.
Malaysia Airlines issued a terse statement noting Bellew's "unexpected announcement" and pointing out that he had recently reiterated his commitment to the airline.
Bellew was appointed CEO of Malaysia Airlines in July 2016 after the surprise resignation of German turnaround specialist Christoph Mueller, who had introduced a drastic cost-cutting plan that involved axing thousands of jobs.
The devastating MH370 and MH17 disasters had pushed the perennially loss-making airline to the brink of bankruptcy as bookings dried up.
Flight MH370 disappeared in March of that year, en route from Kuala Lumpur to Beijing with 239 passengers and crew.
Four months later, MH17 was blown from the sky by a suspected Russian-made ground-to-air missile over war-torn Ukraine, killing all 298 passengers and crew.
Bellew said in a statement that he was "excited to return home to Ryanair and take up the challenge to grow the operation sustainably".
There was no immediate indication from Malaysia Airlines who would replace Bellew as CEO but the carrier said its turnaround plan "remains on track and on schedule".