The aviation industry is suffering on multiple fronts from the growing use of personal electronics powered by lithium-ion batteries. The appeal of the batteries is their high efficiency. The downside is they have a troubling potential to cause catastrophic mid-flight fires.
Lithium-ion batteries are in almost every portable device on the market, from cellphones and cameras, to laptops and tablets. They’ve been adopted so widely because of their high power-to-weight ratio, great energy efficiency, and long life. The technology also runs most electric and hybrid vehicles.
A growing number of airlines are offering tablets as in-flight entertainment. Among them are Thai Airways, Hawaiian Airlines, low-cost Singapore carrier Scoot, TAP Portugal, Israel’s flag bearer El Al, and Qantas’s Jetstar.
The problem is in the stowing. When stacked and stored for charging in an enclosed space, like a galley cart, it’s been proven the batteries could catch fire and explode, as reported by aviation trade publication RunwayGirlNetwork.
The Federal Aviation Authority (FAA) and the Civil Aviation Authority of Singapore conducted a study to see under what conditions the phenomenon called thermal runaway may occur.
Thermal runaway happens when a temperature increase near a lithium-ion battery releases energy that causes the temperature to further increase, resulting in an uncontrolled positive feedback reaction—and eventually a fire.
Ten experiments were conducted in a Boeing 737 test plane where tablets were stacked in a galley cart following airline and manufacturer guidelines. Scenarios included a nearby heat plate and an external alcohol fire.
In some experiments, the tablets indeed caught fire. The aviation authorities concluded that the accumulation of flammable gasses in the galley cart could lead to an explosion that would blast open a galley cart door with the “potential to emerge out of the galley cart and spread to the adjacent structure and materials of the aircraft cabin.”
The report recommends additional study to determine a safe way to store tablets.
Fires can also break out even with a single device.
The latest in a growing list of incidents happened on March 15, when a lithium-ion battery caught fire in an overhead bin on a KLM flight from Amsterdam. The Boeing 777 had just landed in Bangkok when smoke was noticed and a fire erupted; it was quickly extinguished by the flight attendant.
— SixContinentChick (@Accone) March 15, 2015
Air France’s latest safety video warns passengers not to move the seat if they drop their phone between the cushions (view at 3:28). The advice is based on an incident in December 2010 in which a fire broke out on a Boeing 777 Paris-bound flight from Atlanta, Georgia. A passenger’s cellphone fell into the seat and when the chair moved, the seat mechanics crushed the battery causing an internal short circuit that resulted in a fire.
There as also been at least two incidents of an e-cigarette, also powered by lithium-ion batteries, catching fire in a checked bag. In one incident, on Aug. 9, 2014 at Boston’s Logan Airport, a fire broke out in the cargo hold and the plane had to be evacuated. The second was Jan. 4, 2015 at Los Angeles International Airport, when a checked bag caught fire in the baggage hold area. The FAA recommended in a Jan. 22 report, that e-cigarettes only be permitted in cabin luggage.
The greatest danger caused by lithium-ion batteries is when they’re shipped as cargo.
Three freight planes with lithium-ion battery shipments have caught fire in recent years. In two cases the fires caused fatal crashes—a UPS plane that crash landed in Dubai in 2010, and an Asiana Airlines plane that crashed into the Korean Strait in 2011. In the third case, in 2006, the UPS pilot was able to land in Philadelphia and the crew escaped, but the plane was destroyed beyond repair.
Malaysia Airlines Flight MH370, which disappeared on March 8, 2014, without a trace, was carrying about 440 pounds of lithium-ion batteries. A battery-caused explosion is one of the many theories to explain what happened.
In one test by the FAA, 5,000 lithium-ion batteries were placed in a cargo container with a cartridge heater meant to simulate a single faulty battery that overheats. The one bad battery caused a chain reaction, which resulted in an explosion that blew open the container door and within seconds all was in flames. (see video below at 3:10 min)
A few months later, the FAA conducted another test in which they placed a fire-suppression agent in the box. The result was the same.
As of Jan. 1, the International Air Transport Association banned shipping lithium metal batteries as cargo on passenger planes unless they’re packed with the equipment that uses them. Some carriers, such as Qantas have banned lithium-ion battery shipments from freight planes as well.
The main issue for the airlines is that although the risks of lithium-ion batteries are becoming clearer and clearer, more research needs to be done to establish regulations and best practices, particularly for inflight personal devices. In the meantime, the airlines have the liability of living with the known risk, but don’t have enough means to mitigate them.