US testing of lithium batteries alarms aviation officials
WASHINGTON (AP) — International aviation officials are trying to quickly come up with safer packaging for cargo shipments of lithium-ion batteries on passenger planes after U.S. testing confirmed that aircraft fire suppression systems can't prevent overheated batteries from causing powerful explosions and fires.
The hazardous cargo committee of the International Civil Aviation Organization, a U.N. agency, met this week in Montreal. Officials familiar with the discussions said the panel heard a detailed presentation by aircraft manufacturers and pilot unions on the potential for the batteries to cause an explosion and resulting fire capable of destroying a plane.
The committee agreed to create a special working group to try to come up with packaging batteries that would contain any fire or explosive gases to the inside of the package, officials said. If the working group cannot come up with such packaging, officials said they will consider it likely that a formal proposal to ban bulk battery shipments from passenger planes will be offered at an ICAO meeting on dangerous cargo in October.
The batteries are used in devices from cellphones to electric cars. It's not unusual for as many as 80,000 batteries to be carried on board a plane. The global battery industry has been lobbying heavily against significant restrictions on battery shipments other than minor changes to current regulations.
Testing by the U.S. Federal Aviation Administration over the past year and a half has repeatedly shown that a single short-circuiting battery in a large shipment of batteries can cause overheating to spread to other batteries. Fire suppression systems have been able to put out the initial flames, but they haven't been able to stop the spread of continually increasing temperatures known as thermal runaway.
The overheated batteries emit a mixture of explosive gases, of which hydrogen is the most abundant. As the gases build up, they eventually explode and ignite an intense fire.
An FAA test in February resulted in a powerful explosion despite being conducted in a pressurized chamber with an atmosphere of 5 percent halon. Halon is the main gas used to suppress fires in the cargo compartments of passenger planes. Triggered by a rise in temperature, fire suppression systems unleash halon until the gas reaches 5 percent of the air in the cargo compartment. It has long been accepted by aviation authorities that this level of halon is enough to put out most fires, including a lithium-ion battery fire.
"We now no longer believe that would be the case," said pilot Mark Rogers, who represents the Air Line Pilots Association in the U.S. and Canada and other international pilot unions on cargo issues in the civil aviation organization's proceedings.
The February test resulted in an explosion in which pressure in the chamber rose from a normal 15 pounds per square inch to 70 psi, according to an agency slide presentation. Without the presence of halon, the explosion was even more powerful, with pressure rising to about 80 psi.
Two safety experts interviewed by The Associated Press described an explosion of that force as "significant." John Goglia, a former National Transportation Safety Board member, said such an explosion could possibly blow a hole in a plane and cause depressurization for passengers without destroying the plane. He pointed to examples of planes that have landed safely after experiencing such a blowout.
Last month, the International Coordination Council of Aerospace Industry Associations, which represents aircraft companies such as Boeing and Airbus, and the pilot unions submitted a joint working paper to the civil aviation organization recommending a ban on bulk battery shipments on passenger planes until safer packaging can be developed. The paper, which is not considered a formal proposal under the U.N. agency's rules, called the threat of battery fires "an unacceptable risk."
The FAA tests show "the uncontrollability of lithium battery fires can ultimately negate the capability of current aircraft cargo fire suppression systems, and can lead to a catastrophic failure of the airframe," the position paper said.
"It has been our consistent position that theses batteries shouldn't be transported until (adequate packaging) standards are in place," Rogers said. "We'll continue to work with the manufacturers on influencing operators and getting the word out that aircraft cargo compartments aren't capable of handling a fire involving these materials."
A growing number of airlines have also said they will no longer accept bulk battery shipments, including Delta, United, Cathay Pacific, Qantas, British Airways and Cargolux.
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