Federal safety officials are still going back and forth, and doing some finger-pointing, over the lithium-ion batteries that have proved so problematic on Boeing’s new 787 jets.
The New York Times Friday had a story in which Deborah Hersman, the chairwoman of the National Transportation Safety Board (NTSB), accused the Federal Aviation Administration (FAA) of accepting test results from Boeing about the batteries that weren’t quite up to snuff about the smoke and fire danger they posed.
Hersman told the press that in terms of the battery, one of its eight cells short circuited and that spread a fire to the rest of the cells. But she said that the tests Boeing did on the battery did not give any hint that they could catch on fire, “and concluded that they were likely to emit smoke less than once in every 10 million flight hours,” according to The Times.
Unfortunately, during two flights last month the batteries got hot and released smoke twice, and caused a fire, after just about 50,000 hours of flight, The Times reported.
A fire that started on a 787 at a Boston airport on Jan. 7 began with a short circuit in one cell and then spread to other cells, Hersman said at her press conference, according to The Times.
But no one had figured out yet what caused that short circuit in that cell that led it to overheat to 500 degrees, spreading to the other cells.
There’s a lot of Monday-morning quarterbacking going on here now, with some scientists saying that the batteries need to be bigger to leave a bigger separation between their cells.
Battery experts said that the finding pinpointed one step Boeing could take to make the batteries safer: It could expand the size of the battery to create more physical separation between the cells. Ralph J. Brodd, a battery industry consultant in Henderson, Nev., said Boeing and its Japanese battery subcontractor, GS Yuasa, could make the design and manufacturing changes needed to do that fairly quickly.
But unless the feds and Boeing folks doing the investigation still have to figure out what made the first cell short circuit, according to The Times.
Two possibilities have already been crossed off the list, namely a mechanical or electrical shock from outside the battery, The Times reported.
Boeing issued a response to Hersman’s comments.
http://boeing.mediaroom.com/index.php?s=43&item=2586
“Boeing welcomes the progress reported by the U.S. National Transportation Safety Board (NTSB) in the 787 investigation, including that the NTSB has identified the origin of the event as having been within the battery,” it said. “The findings discussed today demonstrated a narrowing of the focus of the investigation to short circuiting observed in the battery, while providing the public with a better understanding of the nature of the investigation.”
The Boeing statement continued, “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, and we will not hesitate to make changes that lead to improved testing processes and products.”