One fix Boeing is looking at closely is a way to strengthen the lithium ion battery's ability to contain any internal overheating and to improve the venting system whereby hot liquid or gaseous products exit the battery box and are directed outside the airplane, two sources said.
But the initial flights will simply gather data on how the battery is affected by changes in temperature during the flight cycle as well as the impact of vibrations during landing and take-off.
According to an industry source, one theory Boeing is investigating is that moisture getting inside the battery may have contributed to the recent incidents.
The National Transportation Safety Board, which is investigating the Boston fire, has so far given no indication that it has determined the root cause.
The resumption of flying, even if only for test flights, would be the first glimmer of hope that Boeing is on its way to resolving the plane's technical problems.