Renault's chassis chief Nick Chester will leave the team in a "major restructuring plan" in the French squad's technical team.
The move is seen as Renault taking action over a struggle to master aerodynamics in 2019, which saw the team drop from fourth in the constructors' championship to fifth.
Team principal Cyril Abiteboul had targeted closing the gap to Red Bull, Ferrari and Mercedes, but instead saw McLaren – Renault's engine customer – outstrip them across the campaign.
Abiteboul's recent claims that the Renault power unit is the most potent on the grid made clear that the works team's failings have been on the aerodynamic side, perhaps explaining Chester's departure after almost two decades at Enstone.
"Nick has been a key part of Enstone for almost 20 years," Abiteboul said. "His passion for the team has never wavered, despite experiencing some extremely challenging times.
"More recently, his commitment, technical insight and enthusiasm have inspired us to move from the back of the grid to the front of the midfield. We would like to sincerely thank Nick for everything and wish him every success in the next stage of his career."
Chester added: "I have enjoyed 19 years in a team with great spirit and have worked with an incredibly loyal and talented group of people. I am looking forward to a new challenge and wish everybody in the team all the best for the future."