* Formula One cancels August shutdown
* Teams must now close for three weeks by end of April
* More measures to be discussed on Thursday
* Sport likely to postpone 2021 rules revamp
(Adds reaction)
By Alan Baldwin
LONDON, March 18 (Reuters) - Formula One teams must close for three weeks by the end of April in a move that will allow races to be rescheduled during the European summer and help limit the financial impact of the coronavirus outbreak.
What would have been a record 22-round calendar is already suspended, with last weekend's Australian season opener in Melbourne cancelled and no racing expected until at least the end of May.
The governing International Automobile Federation (FIA) said in a statement on Wednesday that its world Motor Sport Council approved the change to the 2020 regulations to allow the cancellation of a scheduled August break.
The 10 teams must instead shut their factories for three successive weeks between now and the end of April.
"The change was supported unanimously by both the F1 Strategy Group and F1 Commission," the FIA added.
The switch will also help smaller, privately-owned teams survive what threatens to be an existential crisis as their revenues shrink without any reduction in costs.
Multiple F1 sources told Reuters that the teams, FIA and senior Formula One management will discuss further measures in a conference call on Thursday.
That looks likely to involve delaying by a year the introduction of radical new technical regulations planned for 2021.
Teams would otherwise have to devote considerable resources to designing their 2021 cars while also seeking to remain competitive in 2020.
By bringing forward the lockdown, teams can turn off costly windtunnels and freeze development.
Some European countries are in lockdown already as they seek to contain the spread of the virus and many team staff are already working from home or in self-isolation after flying back from Australia.
The lack of an August break will be another blow for employees however, with family holidays having to be cancelled and the prospect of a packed second half of the year with races running into December.
British-based Red Bull said they planned to close their Milton Keynes factory on March 27 for three weeks, subject to developments.
"Whilst we would all love to return to racing, the severity of this global pandemic is changing by the hour and the impact transcends our sport," the team said in a statement.
"We therefore agree with the measures being taken to reduce the risk of transmission and will support any further race postponements that are deemed necessary."
The Spanish, Dutch and Monaco Grands Prix in May all look uncertain but have yet to be postponed or cancelled.
Monaco is likely to be cancelled if not held in late May, due to the logistical challenges of organising the race in the Mediterranean principality, but the Dutch round -- a home race for Red Bull's Max Verstappen -- could switch to August.
The sport is also keen to reschedule lucrative races in China, Vietnam and Bahrain.
Swiss-based Sauber, who manage and run the Alfa Romeo team, said they would close their Hinwil factory from March 23 to April 13.