S. federal aviation officials have urged airlines to take voluntary measures to reduce the risk of overheating lithium batteries to cause shipping fires, suggesting that regulators are increasingly concerned about the threat posed by air transport of batteries.
A joint Parcel Service plane crashed in Dubai last month, killing two pilots.
The Federal Aviation Administration publicly acknowledged Boeing 747 for the first time in Friday's Security directive-
400 of people carry a large number of lithium batteries.
The smoke that came out of the main cabin of the plane when it caught fire, used to transport the goods, was too thick, and the pilots told air traffic controllers that they could not see their instruments when they tried to land the plane.
Dubai authorities are leading the investigation of the accident with the assistance of the National Transportation Safety Board and the FAA.
The cause of the accident has not been determined.
The safety directive urges airlines to require shippers to identify bulk battery shipments in shipping documents.
It also recommends storing battery cargo in the cargo hold on the belly of the aircraft, where there is a halon gas fire extinguishing system.
The main cabin of the cargo or passenger plane does not require a fire extinguishing system.
Since the beginning of 1990, dozens of battery-lit incidents have occurred during flight or cargo handling.
However, the exact cause of many fires is not clear.
The FAA's safety directive says recent research by its scientists suggests that when batteries are exposed to high temperatures, they have the potential to produce "heat out of control", a reaction that causes itself
Heat and release the energy stored by the battery.
The safety directive states that the cargo hold fire may be hot enough to ignite the battery even if it is not involved in the initial fire, "creating a risk of catastrophic events ".
Once a battery goes through heat out of control, it generates enough heat to touch the heat out of control in other nearby batteries.
Lithium battery-
For example, the kind commonly used in watches and cameras --
There will be enough explosions to destroy the cargo hold.
According to the directive, the FAA test of up to six loose lithium metal batteries stored in steel containers found that when exposed to high temperatures, they produce enough explosive force
"Containers that have not been approved and tested at the moment are able to adequately contain known effects of accidental lithium metal battery ignition," the safety directive said . ".
"The design of ordinary metal containers, barrels and barrels cannot withstand the fire of lithium metal batteries.
"FAA officials declined to say at what temperature the battery was getting hot out of control or exploded.
The Halon fire extinguishing system used in the cargo compartment of passengers and cargo aircraft cannot extinguish fire caused by lithium metal batteries.
However, these systems can put out fires caused by lithium-ion batteries, which are similar to rechargeable batteries used in many mobile phones and laptops.
Lithium-ion batteries are also flammable and canigniting.
The safety instructions say they can produce temperatures that are very close to the melting point of aluminum, which is what is usually made of outside the aircraft.
John Cox, an air safety consultant and former airline pilot, said the safety directive indicates that lithium battery fires are more likely to spread than before.
In January, the Pipeline and Hazardous Materials Safety Authority proposed new regulations requiring lithium batteries to be considered dangerous goods.
The battery shipment must have special packaging and the workers who ship the battery must receive special training.
There must also be special labels and pilots must tell them that lithium batteries are contained in the goods.
These regulations, which have not yet been finalized, have been strongly opposed by the electronics industry, manufacturers and some freight companies including UPS.
Industry officials estimate that the proposed regulatory costs will exceed one billion dollars a year.