By Alwyn Scott
NEW YORK (Reuters) - The lithium-ion batteries used in Boeing Co's 787 Dreamliner are getting x-ray scans to help investigators determine what caused them to overheat and in one case catch fire.
The scans, scheduled to start this week, are not expected to delay the resumption of passenger flights on the high-tech jet. Airlines are phasing the 787 back into schedules over the next six weeks after the failure of two batteries grounded the fleet in January.
The National Transportation Safety Board has hired a Maryland contractor to work weekends to scan up to six batteries in an effort to "avoid potential future accidents involving this type of aircraft battery," the agency said. The batteries have not been installed in aircraft and must be shipped to the company as hazardous materials.
The urgent request allows the NTSB to hire a specific company to perform the scans quickly, rather than putting the work out to bid. The NTSB said the it doesn't reflect any unusual urgency or shift in the investigation.
"There's nothing that's changed," said Peter Knudson, an NTSB spokesman. "Our investigations are by their very nature urgent."
Still, the hiring of a contractor to closely examine both tested and untested cells provides further detail about an investigation that has drawn worldwide attention since the entire fleet of 50 Boeing planes was grounded on January 16, after a second battery overheated on a flight in Japan.
The NTSB has published hundreds of pages of findings about the Boston fire, and conducted two rounds of hearings last month. It is expected recommend changes to the Federal Aviation Administration when it concludes the investigation, likely by the end of the year.
Boeing said it is fully supporting the NTSB investigation and working with customers to install a redesigned battery system and return Dreamliners to passenger service.
The NTSB gave notice on Friday that it was hiring Chesapeake Defense Services to perform computed tomography (CT) and digital radiograph (DR) scans on up to 48 cells. Each battery has eight cells. Both techniques use x-rays to peer inside materials.
Chesapeake, based in Maryland, declined to comment. The company's website says it has a sophisticated system to take detailed x-ray pictures and assemble them into a three-dimensional image.
The NTSB said that as part of its investigation, it also plans to perform "tear-down examinations" of the 787 batteries. It wants the cells carefully scanned to reveal as much as possible about them before they are disassembled. The scans will look at batteries before and after they have been put through test conditions.
The batteries are not used for main flight functions aboard the 787, but serve as back-up power sources and are used to start an auxiliary generator that runs on fuel.
After the two incidents, Boeing added more safeguards, including a steel enclosure that it says will prevent a battery from catching fire. The FAA approved the changes last month, lifting the ban on flights that lasted more than three months and cost airlines and Boeing millions of dollars.
Boeing says that in both incidents, the existing fail-safe system worked. There was no loss of life or significant injury in either incident.
(Editing by Alden Bentley)