There is no place for a fire on an airplane. And if there is a fire, it should not overwhelm fire-suppression equipment.
Here is another no-brainer: lightweight, portable energy is necessary for our modern way of life. Smartphones, laptops, power tools, and even some vehicles depend on lithium batteries. The ubiquitous nature of these modern electronic devices has, in turn, increased the need to ship the batteries that power them.
The same high-energy density that makes lithium batteries such a great way to store electricity can also introduce a fire hazard. A fault in the battery, such as a flaw in the manufacturing process, can cause a fire. Even if a fire starts elsewhere, a lithium battery makes for formidable fuel. When a fire spreads from cell to cell within a lithium-ion battery, it can burn at 1,100 degrees Fahrenheit.
While international air regulations prohibit bulk shipment of lithium batteries on passenger airplanes, the NTSB investigated one cargo aircraft fire in the U.S., and we participated in two foreign-led accident investigations of cargo aircraft where lithium battery fires were suspected.
In late 2010, UPS flight 006 crashed minutes after takeoff from Dubai, UAE. The crew reported an onboard fire but was unable to land their 747 before fire consumed the aircraft. Both crewmembers lost their lives, and the aircraft and cargo was destroyed. The investigation found that a large fire that developed in palletized cargo on the main deck caused the crash. This cargo consisted of consignments of mixed cargo that included a significant number of lithium-type batteries and other combustible materials. The fire escalated rapidly into a catastrophic uncontained fire. The hazardous smoke and fumes entered the cockpit and upper deck simultaneously, obscuring the crew’s view and creating a toxic environment.
Ten months later, Asiana Airlines flight 991, a 747 cargo flight, crashed on its way from Incheon, South Korea, to Shanghai, China. The two pilots on board the aircraft died. The NTSB assisted Korea’s Aviation and Railway Accident Investigation Board (ARAIB) in investigating the crash. The ARAIB determined that a cargo fire that developed on or near two pallets containing dangerous goods (hazardous materials), including hybrid-electric vehicle lithium-ion batteries and flammable liquids, caused the crash. The ARAIB could not pinpoint the cause of the fire, but it determined that the flammable materials and lithium-ion batteries that were loaded together were a contributing factor.
This year, we recommended that the Pipeline and Hazardous Materials Safety Administration (PHMSA) take action in response to the 2011 crash. We asked PHMSA to take the following steps:
- require that lithium batteries carried as cargo be segregated from flammable liquids, and
- establish maximum loading density requirements for lithium batteries and for flammable liquids to allow such a fire to be effectively managed by onboard fire suppression capabilities.
PHMSA has suggested other actions that could also meet our intent. Whatever solution
PHMSA develops, U.S. aviation cannot ignore this potential hazard.
Thankfully, lithium battery failures are rare, and new research and meaningful efforts are underway to make them rarer still. On April 11 and 12, 2013, we conducted a public forum on lithium battery safety. Since then, the Federal Aviation Administration (FAA), in conjunction with the Commercial Aviation Safety Team, has established a joint government–industry working group. The group is developing ways to make lithium battery fires less likely in aviation and to reduce the consequences in case they do occur.
We have issued several other lithium battery-related safety recommendations to the FAA and PHMSA encouraging them to share critical safety lessons learned, implement mitigations, and conduct research into safety improvements. Other NTSB recommendations about the certification and testing of lithium batteries aim to make such fires less likely.
We continue to share our lithium battery investigation findings and advocate safety recommendations. We participate in the UL-initiated Battery Safety Council and attend industry outreach events and seminars, such as the NASA battery forum and seminars from the Knowledge Foundation.
Lithium batteries are not going away; they are far too useful. But we must ensure that each and every shipment of lithium batteries poses minimal safety risk. That is why our Most Wanted List calls on regulators and others to Ensure the Safe Shipment of Hazardous Materials, including lithium batteries in aviation.