Boeing has begun certification tests of its redesigned 787 battery system and expects to hand over the results of all scheduled tests to the Federal Aviation Administration “within the next week or two” for a decision on whether the grounded passenger jet can return to flight, a company official told reporters Friday morning.

Ron Hinderberger, vice president of 787-8 engineering, declined to speculate how long the FAA might take to review the results but said Boeing had already passed many, if not all, of the tests before submitting its plan to the FAA last month. The FAA approved the certification test plan on Tuesday.

Speaking to reporters 14 hours after his bosses provided a 787 battery update via webcast from Japan, Hinderberger also gave more details about the fix itself.

He described the glass laminate that will insulate the lithium-ion battery cells from each other, the stainless steel containment box that will prevent any overheating from igniting, and the one-inch titanium tubes that will vent any overheating from the battery out of the airplane.

“With these changes, we think the likelihood of a repeat event is very unlikely,” Hinderberger said. “That said, I have no intention whatsoever of sitting here in front of you today and telling you we will never have a battery failure.”

The 787 Dreamliner was grounded in January after a pair of smoky battery incidents aboard Japanese-owned planes, one parked in Boston and one flying over Japan. Boeing had delivered 50 787s by that point, including four made in North Charleston.

The National Transportation Safety Board has been investigating the Boston fire while its Japanese counterpart has been investigating the other incident. While the root cause of the battery malfunctions has not been determined, the NTSB did conclude a short circuit led to “thermal runaway” in the battery.

Hinderberger disputed that determination during Tuesday’s conference call, instead calling it “thermal propagation.”

Terminology aside, he said, Boeing has taken the battery issue extremely seriously, drawing in hundreds of engineers from around the company and outside to develop what is being advertised as a comprehensive and permanent fix.

Boeing South Carolina was not involved in either the fix and is not involved in the testing, a spokesman confirmed.

Check back later for more details.

Reach Brendan Kearney at 937-5906 and follow him on Twitter at @kearney_brendan.