Boeing’s Battery Fix Preserves 787 Systems

By Michael Mecham
Source: Aviation Week & Space Technology
April 29, 2013
Credit: Boeing

With pictures of emergency ground crews swarming 787s still fresh in their minds, Boeing's engineers say they have devised a solution so foolproof that pilots will not need to interrupt a flight should a lithium-ion battery failure occur.

“The worst-case battery failure doesn't even require the airplane to divert,” Vice President and Chief 787 Engineer Mike Sinnett said as the company rolled out a team of more than 300 engineers to put the 50 grounded 787s back into service. Boeing has acted not by redesigning the aircraft's electrical architecture, which depends on the high power ratings of lithium-ion (Li-ion ) batteries for initial starts, but by modifying the batteries and enclosures, he says.

The company acted after the FAA's April 19 approval of its solution to prevent thermal runaways from spreading catastrophically from cell-to-cell in either of the aircraft's two 32-volt Li-ion batteries.

All the 787s Boeing had delivered since September 2011 were grounded by the FAA, Japan Civil Aviation Bureau (JCAB) and other national emergency airworthiness directives following two incidents on aircraft operated by Japanese airlines. They acted after a fire broke out in the aft unit of a Japan Airlines (JAL) 787 at Boston's Logan International Airport on Jan. 7, and an All Nippon Airways (ANA) 787 en route from Tokyo to Yamaguchi had to divert to Takamatsu, on the island of Shikoku, on Jan. 16 when fumes escaped from its forward battery enclosure.

The grounding left eight carriers with airplanes in an aircraft-on-ground (AOG) situation at 17 locations worldwide, meaning they could not fly until repaired. In the U.S., United had six 787s at four airports; in Japan, Boeing said ANA and JAL had 24 spread across six airports.

By April 24, Boeing's engineering teams were installing kits in 10 of the grounded aircraft and nine of the 25 undelivered 787s parked at its factories. The company was working in the sequence of deliveries, 787 Program Manager Larry Loftis said. That scenario favors ANA and JAL, which have a combined 24 aircraft,

Boeing suspended deliveries after the FAA and JCAB acted, and it does not expect to resume them until early May. But Chairman/CEO James McNerney says it can still meet its commitment to deliver more than 60 787s this year because it kept producing during the flight suspension.

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