Air New Zealand's engineering division chief Craig Sinclair is leaving the airline for other business interests.
Sinclair has been in charge of the airline's move to send heavy maintenance of its big aircraft overseas, meaning big job cuts across the engineering division.
His job will be taken over by AirNew Zealand Engineering Services (ANZES) general manager Chris Nassenstein.
The airline said he had told them of his intention to resign after returning to work from annual leave earlier this year.
A press statement said Sinclair "would be leaving to pursue personal business interests once ANZES union members had voted on their counter-proposal to retain wide body heavy maintenance in New Zealand".
Union members narrowly rejected a rescue plan which would have meant big cuts in pay and conditions for many.
Sinclair was seen as a potential candidate for the post of chief executive, which became available last year after Ralph Norris left for Australia.
Rob Fyfe, who joined the airline around the same time as Sinclair in 2002, eventually got the top job.
Nassenstein joined Air NZ last year from Air Transat in Canada where he had been senior vice-president, technical operations and customers.
On his appointment, Air NZ said Nassenstein had "considerable experience ... in airline engineering and maintenance organisations including Air Transat, Air Canada and Lan Chile".
Fyfe said Sinclair would leave the airline once work related to the restructuring of ANZES had finished.
