Question: Battery issues on the Boeing 787 Dreamliner were in the news a few years ago, but there has been little information on the changes that were made and why Boeing now feels the problems have been addressed. What are your thoughts on the safety of the lithium battery and the Boeing Dreamliner?
— submitted by reader Rob C., Mich.
Answer: Boeing, working with the NTSB and safety certification firm UL, did extensive testing on the Dreamliner battery. Many changes were made in the manufacturing process in an effort to improve reliability and safety of the battery.
Boeing, wisely, decided to improve the failure tolerance of a battery in thermal runaway in the 787, in addition to the improvements in the battery manufacturing. If a battery thermal runaway does occur, it is contained within the battery box and the vapor is vented overboard.
Lithium batteries provide a lot of power for their weight; consequently, they are the battery used in most electronic devices. The 787 uses lithium batteries for the same reason.
But Lithium batteries can spontaneously overheat and have a thermal runaway. This is not common but does happen. This requires safety mitigations to bring the risk to an acceptable level. Boeing’s improvements to the 787 appear to have been successful, although there was another battery event in November 2017.
Lithium batteries present a risk. We are going to have to monitor them very carefully to maintain the necessary level of safety. Keeping them out of the cargo holds is a good idea.
As for the safety of the 787, I have no question it is a safe airplane. I would fly on it without a second thought.
Q: Captain Cox, I understand that lithium batteries are only permitted in carry-on luggage. What if someone accidentally left one in their checked luggage? Are checked bags scanned for these lithium batteries before loaded?
— Dan K., Va.
A: The bags are scanned for security, not specifically for lithium batteries. If you leave a lithium battery in your bag it will travel with you. It is safer for the battery to be in the cabin so that if a thermal runaway occurs the cabin crew can deal with it. This is why some airlines have recently instituted bans on so-called “smart bags” in checked luggage, as they contain lithium ion batteries.
Q: How dangerous is old wiring? And also how dangerous are the lithium ion batteries? It scares me, keeps me from flying.
— Nessie, Belgium
A: Aging wiring is an issue the industry has faced for many years. The maintenance and inspection of wiring has improved in the last decade. I would not say that wiring in older airplanes is dangerous, however it does require careful inspection and maintenance.
Lithium batteries are an increasing problem. The proliferation of these powerful batteries in so many devices guarantees that there will be thermal runaway events on airplanes, as happened with a certain model of smartphone last year. Flight crews are trained but this training should be improved. The essential factors are how can the device be captured without endangering the crewmember and how can it be contained. Better guidance and tools are needed for flight crewmembers.
I respect your fears, but please remember flying is the safest means of transportation. I encourage you to fly when you want to travel; it is safe and getting safer.
John Cox is a retired airline captain with US Airways and runs his own aviation safety consulting company, Safety Operating Systems.
