Boeing Co has asked the Federal Aviation Administration (FAA) for permission to conduct test flights of its 787 Dreamliner, suggesting the company is making progress in finding a solution to the battery problems that grounded the entire 787 fleet last month.

Boeing said it has submitted an application to conduct test flights. The FAA stated it is evaluating the company’s request.

Boeing would test a potential fix for the problem that caused two batteries to burn on 787s last month. But passenger flights would still be weeks if not months away, according to Reuters.