Sam Michael resigns as Williams F1 technical chief
Sam Michael has resigned as Williams technical director but will not leave his post until the end of 2011.
The team's chief aerodynamicist Jon Tomlinson has also resigned.
Williams, who have won nine team titles, have failed to take a single point from the opening three races.
Team boss Sir Frank Williams said: "Sam and Jon have resigned to give the team the opportunity to undertake the changes necessary to get back to the front of the grid."
Williams have already made a change to their technical department as the British team announced that Mike Coughlan will return to F1 as their chief engineer in June.
The team, which made its F1 debut in 1978, has failed to translate its promising pre-season form into race performance.
Reliability problems, including transmission and hydraulic issues, meant neither Rubens Barrichello nor Pastor Maldonado finished the opening races in Australia and Malaysia.
Barrichello finished 13th at the last race in China but Maldonado was 18th and saw Heikki Kovalainen's Team Lotus finish ahead of a Williams for the first time.
Michael as the head of the team's technical department has been under pressure to reverse the team's fortunes but he and Tomlinson have made the decision to stand down at the end of the campaign.
"Both Sam and Jon are talented and driven people who have worked hard for Williams over 10 and five years respectively," added Williams, who co-founded the team with engineering director Patrick Head.
"Nonetheless, they have recognised that the team's performance is not at the level that it needs to be and have resigned in order to give the team the opportunity to regroup and undertake the changes necessary to get back to the front of the grid.
"Both will continue to work in their present positions through until the end of the year to ensure that the team maintains focus and momentum during the 2011 season.
"We are very grateful to Sam and to Jon for their professional approach."