But LaHood said the results of the Boeing plan the FAA was approving Tuesday would go along way toward determining the readiness of the 787.
“This comprehensive series of tests will show us whether the proposed battery improvements will work as designed,” LaHood said. “We won’t allow the plane to return to service unless we’re satisfied that the new design ensures the safety of the aircraft and its passengers.”
LaHood came under fire in January for declaring that the 787 was "safe" for passengers to fly on a week before the plane was grounded by the FAA.
The FAA ordered U.S. airlines to stop flying the 787 last month after a series of incidents involving battery defects sparked at least one onboard electrical fire. Other worldwide aviation agencies quickly followed suit, leading to a worldwide shutdown of the airplane.
The National Transportation Safety Board (NTSB), which is conducting its own 787 investigation, has attributed the battery fires to short-circuiting and accelerated temperature increases known as “thermal runaway.”
The NTSB has additionally questioned the FAA’s original certification of the Dreamliner airplane.
FAA Administrator Michael Huerta said on Tuesday that he was "confident" in the agency's new certification requirements for the 787.
“We are confident the plan we approved today includes all the right elements to conduct a comprehensive evaluation of the battery system redesign,” Huerta said in a statement. “Today’s announcement starts a testing process which will demonstrate whether the proposed fix will work as designed.”
The FAA said it will have agents present during the 787 battery retesting, address a criticism of examinations of the plane, when Boeing was allowed to "self-certify" some of its components.