The Boeing 787, commonly known as the Dreamliner, was heralded as one of the most technologically sophisticated new aircraft in the world. But severe technical problems have led to the Dreamliner fleet being grounded across the globe. Can the aircraft recover from this setback?
When it made its maiden voyage in 2011, the Boeing 787 became the greenest airliner in commercial service. The plane, which seats between 210 and 290 passengers, is Boeing's most fuel-efficient airliner and the first major airliner to be built primarily of carbon fiber to reduce its weight. The $207 million plane supports a wide range of new features, such as auto window-tinting and more comfortable pressurization, yet consumes 20 percent less fuel.
In mid-January, however, Boeing's new dream was interrupted.
After a fire on a parked Japan Airlines 787 in Boston and an in-flight warning about smoke in an electrical compartment on an All Nippon Airways Dreamliner, the United States Federal Aviation Administration (FAA) on January 16 ordered the entire U.S. fleet of Dreamliners - all of them property of United Airlines - to be grounded, and other nations quickly followed. This leaves the 50 Dreamliners currently in service worldwide sitting idle until Boeing and national transportation authorities can determine the source of the problem.
The focus of the initial investigation has been on the Dreamliner's lithium-ion battery system, which is used to power the plane's auxiliary power unit. This unit activates when the plane is parked and the engines are idle. The lithium-ion batteries are responsible, in part, for the plane's fuel-efficiency: the batteries offer an ideal combination of high power but low weight. Lithium-ion delivers a lot more energy than similar batteries made of other metals because it's more electropositive, which results in higher energy density.
In fact, lithium-ion batteries offer twice the energy density of nickel-metal-hydride batteries and four to six times as much density as the lead-acid batteries found in automobiles, according to the Wall Street Journal
. They are commonly used in laptop and tablet computers, cellphones, and other small devices that require high power. A drawback, however, is that lithium-ion batteries can be very flammable.
Boeing has explained that the lithium-ion batteries for the Dreamliner are manufactured by Japan's GS Yuasa under a subcontract with the French company Thales. Other companies contribute to the plane's electrical systems as well, most notably United Technologies. Since the grounding of the Dreamliner, a number of agencies and companies in the U.S., Japan, and France have worked together to isolate the problem, Reuters
The FAA made a site inspection of GS Yuasa's headquarters in Kyoto, Japan, and the company noted that it is "fully cooperating in the investigation to determine the cause" of the problem. Meanwhile, the U.S. National Transportation Safety Board (NTSB) is conducting a new round of testing on the plane's systems in Arizona after the first round of tests proved inconclusive.
The problems have also raised questions about why the FAA initially approved Boeing's use of the batteries, which have been known to catch fire and can be hard to extinguish when they do. Although Boeing has equipped the Dreamliner with a system to extinguish any fire resulting from the battery and vent toxic gasses out of the plane, the two recent incidents have raised serious questions about safety regulations.
The biggest issue, however, is why the batteries caught fire in the first place. Examination of the Japan Airlines plane revealed evidence of a short circuit in one of the eight cells that comprise the battery. At first glance, it seemed like a problem caused by a reaction called "thermal runaway," which can happen when a lithium-ion battery is plugged in to recharge for too long, raising its temperature and eventually causing the battery's electrolytic solvent to turn into a flammable gas. While the Dreamliner's lithium-ion batteries aren't used during flight, they are continually charged by the plane's onboard generators.
Curiously, the tests on the two batteries revealed that thermal runaway due to overcharging was not the problem. Telemetry from the Japan Airlines 787 determined that its lithium-ion battery was not overcharged and did not exceed its designed voltage of 32 volts, according to a statement by the NTSB, which found similar results on the All Nippon plane.
A greater mystery is that the lithium-ion battery is not unique to the Dreamliner: Europe's Airbus uses similar batteries for some of the systems on its A350 airliners, and those planes have not experienced comparable problems.
As a result, investigators are broadening the search. They are examining the Dreamliner's wire bundles, battery management circuit boards, and other related external components. A second round of tests will examine the faulty batteries again and in more depth in hope of finding an answer.
Boeing has staked much of its future on the Dreamliner, but the FAA has halted deliveries of new planes. Apart from certain minor modifications, any solution to the problem will require FAA approval all over again - a lengthy process likely to further cut into Boeing's profit.
In the meantime, at least two airlines - LOT Polish Airlines SA and Air India - have indicated they may seek compensation from Boeing to recover lost revenue from grounded flights, and it seems likely that other airlines will follow. For Boeing and its partners, the problems have just begun.