Helicopter operator CHC Group has announced the resignation of its president and chief executive, Karl Fessenden.
The Texas-headquartered firm said Mr Fessenden had accepted an opportunity outside the oil and gas industry, effective August 2.
CHC, which has a large North Sea operation, has begun the search for a successor.
In the meantime, Dave Balevic, senior vice president of engineering and operations, will assume the role of interim CEO.
Mr Fessenden said: “This was a difficult decision that I reached after much reflection. It has been a privilege working shoulder-to-shoulder with the best team in the business.
“I am proud of all we have accomplished together. I want to thank the team and the board of managers for their support.
“CHC is in a strong position both financially and competitively in the marketplace, and the course to a bright future is set by continuing to execute our strategy.”
CHC chairman John Gremp said: “On behalf of the board, we thank Karl for his service and many accomplishments during his tenure as CEO.
“We will always be grateful for his leadership at a critical juncture in CHC’s history.
“We have made great strategic and operational progress under his leadership. We wish Karl and his family the very best.
“Karl has assembled a talented and highly capable leadership team, and we are fortunate to have Dave step in as interim CEO.
“He has the board’s full confidence and will ensure continuity while we conduct a thorough search for a permanent replacement.”
Mr Balevic was appointed senior vice president, engineering and operations in May 2015, coming to CHC with 26 years of progressive leadership experience at General Electric.
During his time at GE, he held roles in aviation, power generation and oil and gas.