At the same time the government certified Boeing's 787 Dreamliners as safe, federal rules barred the type of batteries used to power the airliner's electrical systems from being carried as cargo on passenger planes because of the fire risk.
Now the situation is reversed.
Dreamliners worldwide were grounded nearly three weeks ago after lithium ion batteries that are part of the planes led to a fire in one plane and smoke in a second. But new rules exempt aircraft batteries from the ban on large lithium ion batteries as cargo on flights by passenger planes.
The new rules allow the shipment of lithium ion batteries weighing as much as 77 pounds, but only if they are aircraft batteries. Shipments of other lithium ion batteries greater than 11 pounds are still prohibited. The 787's two batteries weigh 63 pounds each. It's the first airliner to make extensive use of lithium ion batteries, which weigh less and store more power than other batteries of a similar size.
The aircraft battery exemption was created for the convenience of the airline industry, which wants to be able to quickly ship replacement batteries to planes whose batteries are depleted or have failed. Sometimes it's faster to do that using a passenger plane.