Airlines around the world grounded their Boeing 787 Dreamliners Thursday after the Federal Aviation Administration ordered U.S. airlines to stop flying them.
The safety of the lithium-ion batteries on the jetliner is at the heart of the FAA decision. The innovative plane runs more on batteries than typical planes and got special FAA permission in 2007 for their use.
But lithium batteries are known to have an occasional risk to overheat and spontaneously combust. A battery pack caught fire in an empty Dreamliner at Boston's Logan airport on Jan. 7. A smoldering battery forced an emergency landing of another one Wednesday in Japan.
Among questions that arise from the incidents and the FAA's decision:
Q: Why use lithium batteries ?
A: Lithium-ion batteries pack more power in a smaller area than other batteries called nickel-metal hydride or nickel-cadmium.
"It's a fundamentally safe technology that is used in cellphones, airplanes, electric vehicles -- you name it," says George Kerchner, executive director of industry group PRBA-The Rechargeable Battery Association. "From an environmental standpoint, you don't have any heavy metals like cadmium or lead."
Q: What risks do lithium batteries pose?
A: Three cargo-plane crashes are suspected to have been caused by fires stemming from packages of batteries:
On July 28, 2011, an Asiana Airlines Boeing 747-400 carrying electronics crashed in the East China Sea, killing both pilots.
On Sept. 3, 2010, a UPS Boeing 747-400 carrying more than 81,000 lithium batteries caught fire after leaving Dubai and crashed, killing both pilots.
On Feb. 7, 2006, fire broke out aboard a UPS McDonnell Douglas DC-8 as it approached Philadelphia. The three pilots escaped after landing, but the plane and most of the cargo were destroyed. The plane contained numerous lithium batteries, but the National Transportation Safety Board wasn't able to pinpoint which cargo caused the fire.
Q: What causes the fires?
A: Because more power is packed more tightly together, lithium batteries can overheat.
The FAA says the battery failures on the Dreamliner resulted in release of flammable electrolytes, heat damage and smoke in the planes. As part of its comprehensive study of the plane, FAA is trying to validate that the batteries are safe.
Q: What will be studied?
A: Donald Sadoway, a battery expert and chemistry professor at Massachusetts Institute of Technology, suggests studying how the Dreamliner batteries are cooled and whether they were manufactured defectively.
Problems with Dell laptop lithium battery fires in 2006 were traced to microscopic shavings of metal getting into the battery during manufacture, turning it into "a toaster oven," Sadoway says.
"Give them a stress test that exceeds the demands of the normal use on an airplane," Sadoway says.
Q: What are the options?
A: Sadoway suggests Boeing could use a nickel-metal hydride battery, which has much less risk of fire and offers about two-thirds the power as a same-size lithium-ion battery.
Mike Sinnett, a Boeing vice president and 787 chief project engineer, has said the company installed multiple levels of protection to prevent the batteries from overheating and wasn't considering switching to another type.
(c) Copyright 2013 USA TODAY, a division of Gannett Co. Inc.
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