( CNN ) -- A flight labeled the `` final '' certification test of an improved battery system for the grounded Boeing 787 Dreamliner was `` straightforward '' and `` uneventful , '' the airplane maker said Friday . The test was an important one for Boeing , which has billions of dollars riding on the success of the new airliner . The U.S. Federal Aviation Administration and similar regulators worldwide grounded the Dreamliner in January after two battery-related fires damaged 787s in Boston and Japan . No one was hurt in the fires . In March the FAA approved a Boeing certification plan to fix the 787 's problematic lithium-ion battery system and prove the new design is safe . Friday 's nearly two-hour flight was the final certification test of that plan . Boeing announces changes to Dreamliner battery system . Boeing `` will now gather and analyze the data and submit the required materials to the FAA , '' the company said in a news release . It said it expects the material to be delivered in a matter of days . The flight left Paine Field in Everett , Washington , at 10:39 a.m. with a crew of 11 , including two FAA representatives , Boeing said , and it returned at 12:28 p.m. `` The crew reported that the certification demonstration plan was straightforward and the flight was uneventful , '' Boeing 's news release said . `` The purpose of the flight was to demonstrate that the new battery system performs as intended during normal and non-normal flight conditions . '' At the time the planes were grounded , 50 787s were flying worldwide . U.S. Department of Transportation Secretary Ray LaHood said in March the Dreamliner will not be allowed back in service until Boeing proves the new design is safe for passengers .
The test is part of Boeing 's work on an improved commercial lithium - ion battery system . Boeing Dreamliner ##s have been grounded since January after two battery fires . Boeing said it will analyze the data from the test and submit material to the FAA .