The July 12 blaze on the Ethiopian Airlines 787 was in a difficult-to-reach space and couldn't be put out by the plane's fire extinguishers, according to British regulators. Only one-third of airliners with such hidden fires can be expected to land safely, an earlier British study concluded.
Lithium cells are lighter, more powerful and longer-lived than other batteries. They power devices from the iPhone to the Boeing 787 and some of its components, including the Honeywell International emergency locator transmitter linked to the London fire.
They can in rare instances overheat in uncontrollable chemical reactions, creating the risk of disastrous fires, as their use proliferates in passengers' personal electronics and aircraft systems, said John Cox, a Washington-based aviation safety consultant who co-wrote a 2013 British Royal Aeronautical Society report on aircraft fires.
"We have never been in a safer time to fly," Cox said. "But when we see any trend in risk that's increasing, we have to look at that more closely."
Manufactured by companies including Energizer and Ultralife, lithium batteries are a $31-billion-a-year market. They're increasingly finding their way onto airplanes in such things as defibrillators and emergency lighting, Mark Rogers, director of the Air Line Pilots Association's dangerous goods program, said in an interview.
"It's more than a 787 issue," Rogers said.
In January, two lithium-ion batteries made by Kyoto, Japan-based GS Yuasa for the 787's electrical system overheated and emitted fumes, prompting a three-month grounding of the plane. Boeing redesigned the battery system, installing a fire-proof case and other protections.
A different type of battery that burns more fiercely, a nonrechargeable lithium metal cell, powered the Honeywell beacon that caught fire in London.
The U.S. Federal Aviation Administration said Friday it will order airlines flying the 787 to inspect the beacon for crimped wires and signs of heating or moisture. The AAIB had recommended the FAA order airlines to disable the beacons.
Investigators are examining whether a wire smashed under the beacon battery cover caused a short-circuit, a person familiar with the probe said.
An FAA log shows 26 instances of lithium-based batteries overheating or catching fire aboard U.S. carriers since 2009. All involved batteries brought on board by passengers or shipped as cargo. None were installed in airplane equipment. Lithium cells made up 78.8 percent of the 33 cases involving batteries in that period.
The FAA issued a safety alert to airlines in 2010 after a United Parcel Service Boeing 747 carrying a shipment of lithium batteries caught fire and crashed in Dubai. The United Arab Emirates General Civil Aviation Authority is to report Wednesday on that accident.
Lithium-manganese-dioxide batteries, like those that power the Honeywell beacons, can be so volatile and difficult to extinguish that the FAA banned their shipment as cargo on passenger planes in 2004.
The market for nonrechargeable lithium batteries such as the one used in the Honeywell device was about $16 billion last year. It's expected to grow 6 percent to 7 percent annually, said Vishal Sapru, energy and environment research manager for consultant Frost & Sullivan, based in Mountain View, Calif.
For rechargeable lithium-ion batteries, the market was about $15 billion and is expected to more than triple to $51 billion by 2018, Sapru said.
"There are lithium batteries everywhere," Hans Weber, chief executive officer of Tecop International, a San Diego-based aerospace consulting company, said in an interview. "Things that are compact and need a fair amount of energy, they all have a lithium battery of some sorts. I don't think there's a choice."
Aircraft manufacturers are using more lithium-based batteries for the same reason they've become the power source of choice in personal electronics: They hold more energy and last longer, said Yet-Ming Chiang, a Massachusetts Institute of Technology professor of materials science and engineering who testified in April at a National Transportation Safety Board forum on battery safety.
The batteries aren't inherently dangerous if used properly, and manufacturers have improved quality and safety, said George Kerchner, executive director of PRBA, the Rechargeable Battery Association, a Washington trade group representing companies including Apple and St. Louis-based Energizer.
About a decade ago, the rate of lithium-battery failures was much higher, partly because of lax manufacturing processes, Weber said.
"We didn't get rid of them 10 years ago when we had more incidences of failure," he said. "Now that there have been definite improvements, we're less likely to get rid of them."
The Honeywell beacon on the Dreamliner is located in a section of the airplane, above the ceiling panels near the tail, where fires have proven deadly, according to U.S. and British regulators.
A fire that started in the ceiling of a Swissair Boeing MD-11 on Sept. 2, 1998, caused the pilots to lose control. All 229 people aboard died when the plane plunged into the ocean near Halifax, Nova Scotia.
It took only 16 minutes from the time the crew detected the fire until the plane became uncontrollable, according to an FAA advisory. There have been at least seven fatal accidents worldwide after fires started in hidden areas, according to the advisory.
Boeing designs many fire protections into its planes, such as isolating flammable materials from heat sources, Marc Birtel, a spokesman for the Chicago-based company, said in an email. "Fire protection is one of the highest considerations at Boeing," Birtel said.
Britain's Civil Aviation Authority, in a 2002 study reviewing earlier fires, concluded only one-third of crews would reach the ground if a fire broke out in a hidden area.
"Large transport aircraft do not typically carry the means of fire detection or suppression in the space above the cabin ceilings and had this event occurred in flight, it could pose a significant safety concern and raise challenges for the cabin crew in tackling the resulting fire," the AAIB said in a July 18 update to the London investigation.
With assistance from Deena Kamel Yousef in Dubai and Julie Johnsson in Chicago.
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