The Federal Aviation Administration has given Boeing permission to conduct test flights of its 787 airliner to gather data about the performance of its lithium-ion battery and electrical system in flight. The announcement was made late on Thursday, several hours after the U.S. National Transportation Safety Board challenged various assumptions underlying the special conditions used by FAA to certify the batteries, which have been implicated in a spate of safety incidents.

Boeing said that it welcomed the latest NTSB findings, including the conclusion that the fire onboard a Japan Air Lines 787 at Boston Logan Airport originated within the battery. The U.S. airframer said that NTSB’s work has narrowed the focus of the investigation to short circuiting in the battery.

Responding to comments by NTSB chairman Deborah Hersmann questioning the terms under which FAA certified the batteries, Boeing commented: “The 787 was certified following a rigorous Boeing test program and an extensive certification program conducted by the FAA. We provided testing and analysis in support of the requirements of the FAA special conditions associated with the use of lithium ion batteries. We are working collaboratively to address questions about our testing and compliance with certification standards. We are working collaboratively to address questions about our testing and compliance with certification standards, and we will not hesitate to make changes that lead to improved testing processes and products.”

The test flights will be conducted under an FAA Special Airworthiness Certificate under the following requirements:

Before flight, the crew must perform a number of inspections that verify that the batteries and cables show no signs of damage.

Pre-flight checklist will include a mandatory check for specific status messages that could indicate possible battery problems.

While airborne, the crew must continuously monitor the flight computer for battery related status messages and landing immediately if one occurs.

Before the initial test flight, the crew must inspect the airplane’s smoke barriers and insulation to verify that they meet the approved design.

Experimental research and development flights are flown with Boeing aircrews that include only personnel essential to the flight.