The grounding of Boeing's 787 Dreamliner has now spread worldwide. All of the countries with airlines flying the airplane have followed the lead of the Federal Aviation Administration in the United States, grounding the new airliner until the chemistry in the lithium-ion batteries used on board can be proven to be safe.
This is the latest, and most serious in a series of incidents that have affected Boeing's flagship airliner since the 787 entered service just over a year ago. Many of the issues, including small fuel leaks, a cracked windshield and faulty indicators, have been attributed to "teething problems" experienced by all new airliners entering service. But the battery issues have proven to go beyond simple growing pains, and have now lead to the first grounding of a U.S. commercial airplane fleet since 1979, threatening to undermine confidence in the Dreamliner, as well as Boeing itself.
The grounding of the fleet comes after a fire on board a Dreamliner in Boston last week was traced to the battery in the rear of the airplane, and pilots in Japan on Wednesday morning were forced to make an emergency landing after smelling smoke in the cockpit and seeing warning lights indicating a problem with the battery located in the front of the airplane. Nobody was injured in either incident, but late Wednesday the FAA issued an emergency airworthiness directive (.pdf) ordering the 787s based in the United States grounded. On Wednesday night and into Thursday, aviation officials in Japan, India, Ethiopia, Chile, Europe and Qatar also grounded the Dreamliner.
Boeing President and CEO Jim McNerney issued a statement late Wednesday saying the safety of passengers and crew are the company's highest priority.
"Boeing is committed to supporting the FAA and finding answers as quickly as possible," McNerney said. "We are confident the 787 is safe and we stand behind its overall integrity." He added the company is working with the airlines and regulators around the clock and that the company "deeply regrets" the impact the grounding has had on passengers.
The 787 was first announced ten years ago this month, and has cost Boeing more than $30 billion to develop according to the Seattle Times. Much of that cost lies in the many innovative new technologies the company used to create the most fuel efficient airliner flying today.
Hailed as the airliner of the future, the 787 is mostly built from composite materials and uses an unprecedented amount of electricity to power many of the systems on board the airplane. The Dreamliner is often referred to as the first composite airliner, but it could just as easily called the most electric airliner ever.
Over the past few decades there has been a trend towards "more electric aircraft" or MEAs as they're known. Airplanes including the Airbus A380 and Lockheed's F-35 Joint Strike Fighter both fall into the MEA category, using electricity to power more systems than previous aircraft. Carrying the moniker of the most electric airliner, the 787 relies almost entirely on electricity to power the systems on board the airplane instead of hydraulics or pneumatics.
Most of the electricity on the Dreamliner is created by six generators, two on each engine and two on the auxiliary power unit in the tail of the airplane. Traditionally, Boeing airliners used only three. These generators provide electricity for the airplane in a similar way that an alternator provides electricity for your car. Though on the 787, a lot more electricity is generated than in the family truckster.
The Dreamliner's electrical system generates nearly 1.5 megawatts, enough to power several hundred homes. With such high electric power demands, the 787 needs high power-dense batteries as an emergency backup source. Though recently it's the high powered, lithium-ion batteries that have been the source of the emergencies leading to the grounding of the 787 fleet.
All of this electrical power has also been decentralized on the 787 with remote power distribution units located in different parts of the airplane. And the 787 electrical system is dominated by a higher power, 235 volts alternating current system instead of the more traditional 115 VAC system.
In a typical airliner "bleed air" is used to power pneumatic and other hydraulic systems throughout much of the airplane. The bleed air is simply high pressure air that is taken directly from the turbine engines that provide the thrust for the airplane. Essentially some of the thrust is bled off of the engines and used as a pneumatic power source. It is a relatively easy source of power to use, but often the bleed air is generating more power than is needed by the systems on board the aircraft, with the excess energy simply being dumped overboard. The pneumatic system also requires hundreds of pounds of ducting and check valves throughout the airplane.
By reducing the use of pneumatic and other hydraulic systems that have been traditionally powered by bleed air and replacing them with electric power, airplane designers are able to save weight and greatly reduce complexity. And because the electric power can be produced and used more efficiently, the airplane needs to burn less fuel to power the systems as well. The result with the Boeing 787 is an airplane that uses electricity instead of pneumatics and hydraulics to do more work, more efficiently than any other airplane in history.
Electric power is used to start the engines, run the cabin pressurization and air conditioning, melt ice that may form on the wings, and electrons even replace hydraulics to actuate the brakes. The only systems that still use bleed air are the anti-ice system for the engine inlets and the hydraulic pressurization. Like a traditional airliner, there are three independent hydraulic systems (left, right and center) on a 787. They are used primarily to move the flight control surfaces on the wings and tail and the landing gear. But in the 787, the center hydraulic system is powered by electric motors rather than air-turbine pumps again saving weight and energy.
Boeing estimates using electrical systems instead of bleed air decreases the fuel burn about three percent. Overall, the 787 reduces the fuel burn about 20 percent compared to a similar size aircraft.
The electrical innovation that is proving the most troublesome is the batteries. The Dreamliner is the first commercial airliner to use lithium-ion batteries as its primary backup power source. The Airbus A380 uses lithium-ion as well, but it is smaller and only used as a backup power source for lighting. Additionally, the chemistry of the batteries is different from what you'd find in your smartphone or hybrid vehicle. The 787 battery is from Japanese manufacturer GS Yuasa and relies on cobalt oxide (CoO2), which has the highest energy density, but is also susceptible to "thermal events" (read: fires). And the cells release oxygen in a fire, meaning it is easy for them to continue burning.
Each of the two batteries on the 787 weighs 63 pounds and are about twice the size of a car battery. After concerns were raised following last week's battery fire on a 787 in Boston, Boeing said the high energy density power provided by the relatively light weight lithium-ion battery was the "right choice" and stands behind their use.
It's no secret that lithium-ion batteries can cause problems according to Dr. Eric Stuve, professor of chemical engineering at the University of Washington. Several makers of consumer electronic products have had battery recalls, including Apple, and Sony recalled millions of the batteries after a contamination led some of its lithium-ion batteries to catch fire.
"These batteries have flammable components, that is well known" Stuve says. "People are very respectful of the chemistry involved."
But Stuve adds that the dangers involved with the batteries can be dealt with through design, just as the danger of the highly flammable jet fuel on an airliner can be dealt with through design.
Indeed Boeing was well aware of the dangers posed by lithium-ion batteries during the design of the 787. The batteries and the airplane as a whole did undergo the most rigorous flight test certification program in airliner history. The lithium-ion batteries were approved by the FAA in 2007 after years of testing and debate over their use on the 787.
There are four controllers on the batteries to regulate the power, temperature and pressure in an effort to prevent a "thermal runaway," though it is now obvious the safeguards on the 787's batteries aren't enough. And the areas where the batteries are located in the tail and the nose of the airplane are designed to contain a fire should one occur, limiting damage to the immediate area and protecting other critical systems on the airplane.
The Federal Aviation Administration wants Boeing to demonstrate that the batteries do not pose a further risk to the 787 before the airplane will be allowed to fly again. Investigators will be looking into whether there is a problem with the airplane's design, or if it is a problem related to the manufacturing of the components or the airplane itself.
Aviation analyst Richard Aboulafia of the Teal Group is leaning towards a manufacturing problem.
"It's not likely that this architecture is fundamentally flawed," Aboulafia says. "One thing that distinguishes this problem is that there were so many airplanes built out of order and before certification was complete. It's a recipe for defects."
Many of the airplanes, including the ANA Dreamliner that was forced to make an emergency landing on Wednesday, were built before the certification of the airplane itself was complete (the ANA airplane was the ninth 787 off of the assembly line). All of these early aircraft had to be reworked with changes made after they had left the factory, and were waiting to be delivered. In the past year Boeing has made a push to increase the 787 production rate causing some concern that the push for a high production rate may compromise quality.
The investigation by the FAA and Boeing could result in further changes being made to the design of the airplane, or changes that may need to be made in the manufacturing.
It is not known when the 787 will begin flying passengers again. The FAA will allow the airplane to return to service if Boeing can demonstrate the batteries are safe. This could include a short term fix to the problem in an effort to get the 50 grounded airplanes flying again. Similar actions have been taken with other airworthiness directives on other airplanes. Though it is likely that it will be many months before a permanent solution is developed for the troubled Dreamliner.
