A fire that broke out last week in a Boeing 787 Dreamliner could have been hot enough to melt the carbon-fiber reinforced plastic that makes up the planes shell, according to the results of tests the Federal Aviation Administration performed last year.
Early Wednesday, Japan's All Nippon Airways grounded all 17 of its Dreamliners after a flight made an emergency landing at the Takamatsu airport in western Japan. Smoke was reported in the cockpit, and the plane's 137 passengers were evacuated.
The incident magnifies concerns about the plane's safety. A fire last week in a lithium battery housed near the tail section of a Japan Airlines plane at Bostons Logan International Airport prompted an investigation by the National Transportation Safety Board and a review by the FAA.
FAA spokeswoman Brie Sachse said the Japan event "will be included in the comprehensive review the FAA began last week of the 787 critical systems, including design, manufacture and assembly."
Boeing spokeswoman Lori Gunter said the company "will be working with our customer and the appropriate regulatory agencies."
On Monday, the NTSB released photos of the fire-damaged battery and the metal box that contained it. An NTSB spokesman would not say Tuesday whether the box kept the fire from damaging anything but the battery.
Paul Jonas, director of the Environmental Test Lab at the National Institute for Aviation Research in Wichita, Kan., said that the box may have contained the fire.
From the photo provided, the box looks like it did the job fairly well, said Jonas, whose lab does testing for the FAA. The fact that they had a box would indicate that they designed for this condition.
In the FAA tests, which the agency performed at its site in Atlantic City a year after it certified the Dreamliner, the temperature of the battery fires reached as high as 2,000 degrees Fahrenheit. The planes polymer skin melts at 649 degrees, according to its manufacturer, Victrex Energy of West Conshohocken, Pa.
John Goglia, a former member of the NTSB who led public hearings after ValuJet Flight 592 crashed into the Florida Everglades in 1996, killing all 105 passengers and crew members, said that problems with lithium batteries catching fire in laptops, cellphones and electric cars were well documented and should have raised a flag with the FAA.
Weve had a long-running issue with lithium batteries, he said. Theyre not allowed to be carried on passenger airplanes.
Goglia said weight was the most likely reason Boeing went with the 63-pound lithium battery, which is lighter and more powerful than other types.
It also burns at high temperatures. In two lithium battery fire tests last year, temperatures peaked between 1,400 and 2,000 degrees, according to a report of the test results. Some of the battery cells exploded and landed more than 100 feet from the fire, and one of the fires burned for more than an hour.
A Boeing safety document from last year shows the location of the battery in a lower compartment near the planes tail section. The compartment, which is not protected by the planes fire-suppression system, contains key electrical systems. The battery, which powers the planes auxiliary power unit, is close to the planes fuselage.
Nearly two years into its debut, 50 Dreamliners are in service worldwide, and 800 more are on order. Boeing planned this year to produce 10 of the aircraft a month at its two final assembly sites in North Charleston, S.C., and Everett, Wash. About 50 percent of the plane is made of a composite material similar to a fiberglass boat. It replaces aluminum, making the plane lighter and more fuel efficient.
In a separate test last year, the FAA exposed a section of the composite material to fire, and photos in the report show a result that looks like Swiss cheese.
Jonas said that 400 degrees is enough to degrade the material. A fire as hot as those in the FAA tests would burn it away.
All youre going to be left with is graphite fibers, he said. If you hold the flame on the composite long enough, it will burn out and just leave the carbon.NTSB photos of damaged battery
FAA report on battery fire testing
Safety document for Boeing 787
By Curtis Tate