Irish LCC Ryanair has announced the resignation of COO Michael Hickey, who has been with the company for 30 years and overseen operations since 2014.

Hickey’s resignation, which takes effect from the end of October, comes after the airline was forced to make hundreds of cancellations, costing the company millions of euros, because of crewing problems related to a government-mandated change in how it allocates vacation time.  Ryanair declined to comment on whether Hickey’s departure was related to that issue.

Before becoming COO, Hickey was director of engineering—a role he took up in 2000. He originally joined the airline as an engineer in 1988.

Ryanair said Hickey will continue in an advisory role to ensure a smooth handover and to wrap up on a number of large projects, including an engine maintenance contract and new hangar projects in Seville and Madrid.

“Over the next three weeks, he will work on an orderly handover of his responsibilities, while Ryanair will commence the process of identifying and recruiting a successor,” Ryanair said.

Ryanair CEO Michael O’Leary said Hickey made an “enormous contribution” to Ryanair.

The airline had to cancel 2% of its flights over a six-week period at an expected cost of €25 million in costs. Ryanair is also grounding 25 of its 400-strong fleet of Boeing 737-800s over the winter as it works through the rostering issue.

On Oct. 9, Ryanair said 99% of the 315,000 customers affected by the cancellations announced Sept. 18 have now been accommodated.

From the second batch of cancellations announced Sept. 27, impacting 18,000 flights between November and March, Ryanair said it has reached solutions for 90% of the 400,000 affected customers.

Ryanair originally said the cancellations were to restore punctuality, which had dipped to below 80%. On Oct. 9, the airline said punctuality has been running at 97% over the last seven days.

Victoria Moores