Passengers aboard Lufthansa Flight 435 at Chicago O'Hare International Airport were settling in for a nine-hour flight this spring to Munich, Germany, when a burning odor floated into the first-class cabin. According to witnesses, the luggage bin above seat 2A was burping smoke.
Flight attendants evacuated first class just before a computer case in the compartment began to spit fire. The crew grabbed extinguishers and sprayed the bin. Someone swung open a cabin door, snatched the case and tossed it onto the ramp. The case erupted in flames. As passengers watched, fire trucks then the bomb squad roared to the scene and put out the blaze. But they found no terrorist device. Instead, authorities discovered a charred laptop computer and a six-pack of melted lithium-ion batteries.
Long before this month's foiled terror plot to blow up planes from Britain to the U.S. and before Dell Computer's mid-August recall of 4.1 million laptop batteries because of fire danger a growing number of transportation and product-safety officials had expressed concerns that batteries in laptops and other electronics pose a serious risk to airplanes for reasons completely unrelated to global terror.
Although the risk is small, the Consumer Product Safety Commission has documented 339 cases of lithium and lithium-ion batteries for portable electronics overheating, emitting smoke and fumes or exploding since 2003. There is no record of a serious injury or death, but the Federal Aviation Administration has logged 60 incidents since 1991. In the past two years, six incidents have occurred on aircraft, including five fires and an overheated flashlight that had to be handled with oven mitts.
In February, a United Parcel Service plane full of packages including lithium-ion batteries was engulfed in flames while landing in Philadelphia. Investigators haven't reached a final ruling on the cause but continue to closely examine the melted shipment of batteries. In October 2004, a plane carrying vice-presidential candidate John Edwards made an emergency landing after a lithium-ion battery exploded in the hand of a television newsman.
Capable of storing an enormous amount of energy in a small package, the lithium-ion battery is perhaps the most popular power source for notebook computers, MP3 players and high-performance cellular phones.
Cellphones are of less concern because their use is barred during flights. In general, they also operate at lower energy levels than computers and thus pose less of a fire risk.
The problem, experts say, is "thermal runaway" a chemical reaction inside a battery cell that generates intense heat so rapidly that it flares out of control. Most of the failures are traced to a short circuit in the cell or the wires that connect the cell to contact points on the battery pack. Richard L. Stern, associate director of compliance at the Consumer Product Safety Commission, says tiny metal shards can contaminate the battery pack during assembly and later pierce the insulation separating the positive and negative terminals. The opposite poles touch and create an electrical spark A defective or damaged battery that is vigorously jostled like a laptop rattling around in a luggage compartment can trigger a flare.
Worries about the possible dangers, of battery short-circuits causing fires, are serious enough that the National Transportation Safety Board held a two-day hearing in July in Washington to discuss the safety of lithium-ion batteries on passenger and cargo planes and the investigation into the UPS fire.
No formal proposal for new regulations has yet been put forward, but regulators are discussing options ranging from tightening manufacturing guidelines for the batteries to potentially restricting their use on passenger jets.