Boeing, which had its 787 Dreamliners grounded earlier has fixed its batteries now. The company is confident that the 200,000 hours of testing time put in by their 500 engineers is enough to prove there is no risk of fire or smoke from the new batteries.

The batteries were submitted for testing at the Federal Aviation Administration (FAA) which had given a pre-approval earlier on Tuesday. Eventually, Boeing is required to complete 20 more certification tests that it hopes to wrap up in two weeks.

Boeing uses Japanese technology to make its 787 batteries and said that it has worked very closely with its Japanese partner in solving “80 potential problems that could lead to a battery fire”.

Boeing will have to also get approval from each country’s aviation authorities, before the Dearmliner jets can be airborne again.