If I declared in 2018 return two accounts me and my wife have in other country with combined amounts of + $10000. If we can't file an FBAR before April 15 what can we do?

The Act also mandates a maximum six-month extension of the filing deadline. To implement the statute with minimal burden to the public and FinCEN, FinCEN will grant filers failing to meet the FBAR annual due date of April 15 an automatic extension to October 15 each year. Accordingly, specific requests for this extension are not required.