Renault has ousted its aerodynamics boss.
The Enstone based team intended to close the gap to Mercedes, Ferrari and Red Bull in 2019, but instead has actually fallen behind McLaren.
Renault is happy with the step it has taken with its engine this year, but Cyril Abiteboul admitted in Austin that the aerodynamics department needs improving.
"We need also to look for a bit stronger technical leadership and making the team stronger in that area where we were a bit lean," he said.
"Our aero department is a big department with very nice facilities, state-of-the-art equipment, so they need to know to deliver more."
Aerodynamics boss Peter Machin has therefore left Renault "with immediate effect".
He will be replaced by Dirk de Beer, who formerly worked at Enstone before switching to Ferrari and most recently Williams.
Renault also said a deputy aerodynamics boss "from another team" will start work at some time next year.