Has Boeing Extinguished its Dreamliner Woes?
A little over a week after Boeing began testing its new battery system for its 787 Dreamliner with the Federal Aviation Administration (FAA), the company has announced that it expects to complete certifications within a matter of weeks, not months.
While most of the testing will take place on the ground, a single test flight has been scheduled as part of the certification process. Mike Sinnett, Boeing's chief project engineer on the 787, said that the new design “eliminates the possibility of fire.”
Even Ray Conner, Boeing's CEO of commercial aircraft, has stated his plans to be on the airline's first flight once the certification is over.
The lithium-ion batteries that caused the Dreamliner fleet to be grounded earlier this year have been around for a while. Despite their weaknesses, the batteries are used in cellphones, laptops and cameras, as well as other aircraft. But the large scale implementation of these batteries in the 787s led to a unique set of problems that led to the fleet's grounding.
In most cases, the batteries are small enough that when they start to fail, the heat they produce instead of power can easily dissipate. On the other hand, the trapped heat can build up much more quickly in a 63-pound Dreamliner battery.
With enough heat, the electrolyte, a central and flammable component to lithium-ion batteries, provides fuel for the battery to burn.
To prevent this, Boeing has started thoroughly protecting each of the eight individual cells that comprise the suitcase-sized battery. Next, the entire battery will be encased in a stainless steel box that has been designed not only to contain but prevent a fire.
Sinnett explained to reporters that there will not be sufficient oxygen to “contribute to combustion” in the case of battery failure or overheating. In the six weeks of testing that has elapsed thus far, engineers only managed to ignite vented gases for 200 milliseconds before the fire went out. And even this required engineers to pump in additional oxygen to coax out a combustion.
The new design also features a pressure release disc that will vent the flammable electrolyte mixture out of the aircraft's exterior. These vent tubes were also designed to eliminate the chance of gases or smoke breaking through into the aircraft.
Although the FAA certification testing is more than halfway over, being certified does not mean the 787 will immediately return to this skies. At this point, it hasn't been said when the Dreamliner will fly again.
Full story at Wired