Boeing unveiled its fix for its troublesome 787 battery on Friday and is aiming to wrap up testing within two weeks.
The company hopes to get quick approval from the Federal Aviation Administration and bring an end to the grounding of the plane that began on Jan. 16. Company executives said the plane could be flying again within weeks, although aviation authorities in the U.S., Japan, and elsewhere will ultimately decide the timing.
Boeing still doesn't know the root cause of the fire on a parked 787 Dreamliner in Boston on Jan. 7, or of the smouldering battery that forced an emergency landing on another 787 nine days later. Boeing executives said they may never know.
Instead, they're building a battery they hope cannot burn.
The battery's eight cells will each be wrapped in an orange tape that won't conduct electricity. A glass-laminate sheet protects the cells from the aluminum case. The wires on top are getting extra heat-resisting insulation. And the whole works now goes inside a new sealed steel tub that looks like a kitchen trash can tipped on its side. If a cell overheats, a titanium hose will carry the gases to the outside of the plane through a new four-centimetre hole in the fuselage.
The changes make it "very unlikely" another battery event will happen, said Ron Hinderberger, Boeing's vice-president for 787-8 engineering.
Boeing hopes the new steel box won't just contain a battery fire, but will prevent one from starting at all by choking off the flow of oxygen and venting the battery gases and air inside the box outside of the plane.
The new design was tested before Boeing proposed it to the FAA. It will be retested so it can be certified for use on the plane, Hinderberger said. That should be done within a week or two. After that, approval will be up to the FAA.
He said it would be inappropriate to speculate on how long that would take.
Boeing shares rose $1.81, or 2.1 per cent, to close at $86.43. They've been rising in recent weeks as investors have been anticipating a fix for the battery problems.
Hinderberger's assessment was more cautious than statements from other company officials, who suggested Thursday the 787 could be flying within weeks.
Each 787 has two of the lithium-ion batteries. The fix will add 68 kilograms to the weight of each plane, Hinderberger said. Weight is a key issue for the fuel efficiency of any plane, and Boeing has struggled to keep the 787 at the weight it promised to customers.
Boeing rolled out the changes first in Japan on Friday morning and then later in a conference call with Hinderberger. All Nippon Airways has 17 Dreamliners -- more than any other airline -- among the world's fleet of 50. The emergency landing in Japan was an ANA 787, while the battery with the fire in Boston was a Japan Airlines plane. About one-third of each Dreamliner -- including the batteries -- are made in Japan.
Boeing officials said it's not uncommon for airplane fixes to be applied when the root cause isn't known. The fixes they plan for the 787 should prevent battery fires and runaway heat buildups regardless of the root cause, they said.
Boeing executives downplayed the parts of the incident that have most worried travellers. They said the only fire was on a connector on the outside of the battery box in the Japan Airlines plane, not in the battery itself. The white gas billowing out the side of the plane wasn't smoke, but electrolyte in gas form, they said.
"We have not ruled out a fire in the battery," NTSB spokesman Peter Knudson said after Boeing's comments. The NTSB is leading its own investigating of the Boston fire and is participating in the investigation in Japan.
-- The Associated Press
The details of the battery fix
Boeing Co. is proposing several changes to the battery on its 787 Dreamliner. Here's a closer look at its plans, which still require government approval:
Non-conducting tape wrapped around each of the eight cells that make up a battery;
Heat-resisting insulation for wiring;
Glass laminate plates between the cells and aluminum case;
Locking nuts on the metal plates that connect each cell;
New tests on each battery cell, and on the assembled battery;
New sealed steel box to house the battery;
Titanium tube to take gases from an overheated battery straight outside through a new hole in the plane.