B787 oppdatering

Boeing Completes Final 787 Battery Test, Awaits FAA Approval

Federal Aviation Administration officials flew aboard a Boeing 787 for a test of the airliner's new battery system that included "normal and non-normal flight conditions" and went off without a hitch.

The "non-normal" flight conditions included "simulating failed engines, generators, pumps and other equipment on the airplane," Boeing spokesman Marc Birtel said. The rigorous 1 hour, 51 minute flight up and down the Oregon and Washington coast was meant to show the FAA that Boeing has solved a battery problem that led to "thermal runaway" aboard aboard 787 Dreamliners in Boston and Japan. All 50 Dreamliners in service worldwide have been grounded since January 16 because of the problem.

Boeing has spent weeks designing and testing improvements to the 63-pound lithium-ion battery after problems arose aboard a Dreamliner at the gate at Logan International Airport and another in flight over Japan. In both cases, the batteries were severely damaged by heat, but damage to the planes was limited to the area immediately surrounding the batteries, one of which is located in the nose of the 787, the other near the middle of the aircraft.

The redesign includes improved separation of individual lithium-ion cells to minimize the chance of what Boeing is calling thermal propagation but the National Transportation Safety Board characterized as thermal runaway. The added insulation is designed to minimize the chance of an overheated cell propagating when one of the eight cells experiences a short circuit.

The new design also houses the battery in a heavy-duty sealed stainless steel box vented directly to the exterior of the fuselage. Boeing believes the new system eliminates the chance of a battery fire. At a press conference in Japan last month, the company even showed a test where propane was purposely ignited inside the steel box, which easily contained the small explosion.

Boeing has tested the new design in the lab and on the ground aboard a flight test aircraft, and in the air aboard a 787 built for LOT Airlines of Poland. Ground testing included "battery failure venting in the containment housing," Birtel said. The FAA will now examine the data from Friday's flight as well as information gleaned from other tests. It is widely expected to approve the redesign, which would allow the aircraft to resume passenger service soon.

Although the Dreamliner has garnered widespread attention for its use of composite materials and fly-by-wire technology, the aircraft is no less groundbreaking for its extensive use of electrical systems instead of hydraulics. The two large lithium-ion batteries aboard each 787 power some systems while on the ground, including starting the auxiliary power unit, as well as serving as back-up power in the event of a loss of power during flight.

The battery's original design was criticized by some experts, including Tesla Motors CEO Elon Musk, as being overly simplistic. The NTSB also was critical of the meltdowns, noting they happened far more frequently than Boeing's initial prediction that we'd see one for every 10 million flight hours. Both occurred after roughly 50,000 hours of flying time.

Boeing says it has several mechanic teams ready to deploy worldwide to retrofit the new batteries in each of the 50 grounded Dreamliners. The teams are drawn from Boeing's AOG (aircraft-on-ground) mechanics, a sort of "special forces" team that is always standing by to assist Boeing customers anywhere in the world. The mechanics will install the new batteries and boxes, as well as drill a small hole in the fuselage of each airplane to allow for the venting of gasses should a battery fail in the future.

There is no timetable for when the analysis will be completed by the FAA, or if more testing will needed. A best case scenario would likely include FAA approval this month and then several weeks for to retrofit the grounded aircraft.

United has indicated it plans on flying the 787 again by May 31, and world-wide service is expected by June.

Boeing is about to run out of parking space outside its factory in Everett, Washington where the 787 along with the 747, 767 and 777 are also built. The company is renting space all around Paine Field, including an unused runway that currently has several partially finished Dreamliners parked nose to tail towering over the smaller, general aviation aircraft at the airport.