A worldwide cargo ban on transporting highly combustible lithium metal batteries on passenger aircraft could be imposed within days, writes Aimée Turner.

ICAO’s Dangerous Goods Panel working group on lithium batteries will meet today in Montreal to review tests carried out in February at the Federal Aviation Administration (FAA) Technical Center in the United States.

These were attended by experts from the International Civil Aviation Organization, the FAA, and their safety counterparts from the European Aviation Safety Agency, together with the aircraft and battery manufacturing industries to determine just how dangerous transporting lithium metal batteries in both passenger and cargo holds really is.

Lithium metal – or non-rechargeable – batteries are used to power a whole range of everyday devices and are routinely carried in the cargo holds of passenger aircraft.

If a lithium metal battery overheats it can lead to thermal runaway and reach temperatures exceeding 760 degrees Celsius. Just one battery could generate enough heat to cause nearby batteries to go into thermal runaway resulting in propagation from cell to cell and package to package. The halon fire suppressant carried on board passenger aircraft – worryingly – has absolutely no effect on lithium metal battery fires.

Scenarios

There was comprehensive testing of all the various chemistries and sizes in a series of simulated cargo fire scenarios using shipping cartons placed in a test Boeing 727 airframe – either through overheating or through directly heating the battery up to 190 degrees Celsius.

Tests showed that smoke caused by the fire quickly engulfed the flight deck within eight or nine minutes of detection. In one test involving 4,800 small cyclindrical batteries used commonly in such things as flashlights, a single battery in thermal runway led to a flash fire, causing an explosion that ripped through the aircraft, blew the flight deck door off its hinges and buckled the airframe. Tests in the hold of a freighter aircraft showed that smoke started to pour into the flight deck within five minutes and became so severe that it soon became fully obscured by smoke.

ICAO flight operations chiefs already believe that on the basis of accepted safety review processes, the transport of lithium metal batteries on passenger aircraft poses an unacceptable risk because – even though the chances of one occurring are remote, the severity of an onboard fire would be catastrophic. They insist that because so little data exists on the size of global shipments of lithium batteries worldwide, the worst case scenario has to be assumed.

The working group will also have to decide by Friday whether to treat all aircraft – passenger and cargo – in the same way. While freighters do not have to carry any fire suppression mechanism under current rules, the aircraft manufacturing industry points out that modern aircraft are certified only to carry general cargo – and not the ‘unique hazards’ of carry dangerous goods such as lithium batteries.

Following the February testing, committee members attending this week’s series of meetings will be asked to consider restrictions up to and including an outright ban on lithium metal battery cargo to be implemented as soon as possible. There may be the possibility of a compromise position which would involve restrictions chiefly on carrying certain types of battery, restricting their quantity and improving packaging. Under existing rules, there are no limits to the number of packages containing dangerous goods that can be transported on any single aircraft.

Concerns

Concern over the dangers of carrying lithium metal battery is nothing new. The United States and several airlines including Cathay Pacific have already had passenger aircraft bans in place for a number of years. ICAO shares their concerns too. ICAO’s air navigation bureau chief Nancy Graham even went so far as voicing the Secretariat’s growing concern with lithium battery cargo safety last November.

Those against a ban claim it is non-compliant shipments and counterfeit batteries that are the source of the problem and that these would simply go ‘underground’ resulting in dangerous shipments finding their way on board passenger aircraft without the airline’s knowledge.

Mark Rogers leads international pilots professional organisation IFALPA’s dangerous goods committee does not accept that. He insists that the fear that something will be done illegally does not represent a reason to codify it in global aviation’s regulations. “To have a situation where we allow unlimited quantities of lithium metal batteries to be shipped on passenger aircraft where, if something were to happen you have no successful technique to put out the fire, is unacceptable from a regulatory standpoint.”

While many support better enforcement, experts still worry however that even perfectly manufactured and prepared shipments could be damaged – and therefore liable to become dangerous.

IFALPA insists there should be a total ban on cargo aircraft as well as passenger, arguing there is no safe way to transport lithium metal batteries and that even rapid depressurisation of the aircraft is ineffective.

With industry estimates of the number of lithium metal batteries being shipped in their billions each year, most agree that the status quo cannot be maintained. As ICAO notes: ‘Concern was expressed that at some point a catastrophic fire would occur on an aircraft and that action had to be taken’ and that, ‘Some members believed that without further action, a catastrophic event was inevitable and that an immediate change to the requirements was necessary’.

Read: