NEW YORK (AP) -- The safety and reliability of the Boeing's new 787 came into question again Wednesday when battery problems led to an emergency landing of an All Nippon Airways flight. ANA and Japan Airlines, the biggest customers for the plane, temporarily grounded all 24 787s they own. Boeing shares fell more than 3 percent.
Just a week, ago the battery on a Japan Airlines 787 ignited shortly after the plane landed at Boston's Logan International Airport, prompting the Federal Aviation Administration to initiate a review of everything about the new airplane, including its entire design and manufacturing process.
Nearly half of all 787s ever produced are now grounded because of safety concerns. The other six airlines flying the plane have no plans to cease operations and government regulators maintain that the plane is safe to fly.
But the two incidents with the plane's lithium-ion batteries raise a host of questions:
Q: What happened with the latest incident?
A: All Nippon Airways pilots on a domestic flight to Tokyo detected a burning smell and received a cockpit message showing battery problems. They made an emergency landing at Takamatsu airport in western Japan, and passengers rode emergency slides off the plane.
Q: If major changes are required, will the FAA ground the planes that are already flying?
A: Theoretically, the FAA could ground the 50 787s that are in service, but no one has suggested it is considering such a drastic move. Regulators have yet to determine the cause of the Jan. 7 Boston battery fire, so it's unclear what a potential fix -- if indeed a fix is needed -- might involve.
Q: How important is the 787 to Boeing's future?
A: It's a prestige airplane, intended to offer more comfort for passengers and much better fuel efficiency for airlines in a state-of-the-art design. At the moment, the 787 is a money-loser. Boeing doesn't expect to begin making a profit on the jet until 2015. But considering that some Boeing models have been built for 40 years (e.g. the 737 and 747), the company still hopes to make money on the 787 over time.
Q: What's the big deal about the 787?
A: Boeing hopes the plane will revolutionize air travel. Half of the 787 is made from carbon-fiber composites, which are lighter and stronger than the aluminum used in traditional planes. That means the jet burns less fuel, a big selling point because fuel is an airline's biggest expense.
The extra strength allows for larger windows and a more comfortable cabin pressure. Composites don't corrode like aluminum, so the humidity in the cabin can be up to 16 percent, double that of a typical aircraft. That means fewer dry throats and stuffy noses.
Q: What else is different about the plane?
A: More than any other modern airliner, the 787 relies on electrical signals to help power nearly everything. It's the first Boeing plane to use rechargeable lithium-ion batteries to start its auxiliary power unit, which acts as a generator to provide power on the ground or if the main engines quit. The batteries -- each about twice the size of a car battery -- allowed Boeing to get rid of a heavier system common on other planes that uses hot air from the outside to start the APU.
Q: Do the lithium-ion batteries pose an added danger?
A: Lithium-ion batteries are potentially more susceptible to fire because, unlike other aircraft batteries, the liquid inside of them is flammable. The potential for fire increases if the battery is depleted too much or overcharged. Boeing has built in special circuitry and other safeguards designed to prevent that situation. In September 2010, a UPS Boeing 747-400 crashed in Dubai after a large number of the batteries it was carrying as cargo caught fire.
Q: Who makes the batteries?
A: Japanese manufacturer GS Yuasa is responsible for the battery and France's Thales Avionics Electrical Systems makes the battery charger system.
Q: How much fuel does this plane save airlines?
A: Boeing designed the 787 to use 20 percent less fuel than comparable aircraft. The Boeing 767-300ER consumes 1,600 gallons of fuel for each hour in flight. With jet fuel currently costing $2.91 a gallon, airlines could save $13,000 during the 14-hour flight between Boston and Tokyo. There is no public data yet on whether the 787 meets Boeing's fuel savings promises.
Q: Does any other plane use composites?
A: Composites are used in smaller amounts on most modern planes. Rival plane maker Airbus is designing its own lightweight composite jet, the A350, but that jet is still several years away from flying.
Q: Didn't it take Boeing a long time to get the 787 airborne?
A: Boeing applied to the FAA to make the 787 in 2003. The first plane flew in December 2009, and six test planes ran up some 4,645 flight hours. The first paying passengers took flight in October 2011, more than three years behind schedule.
Q: Why the delays?
A: Parts for the jet are made by 52 suppliers scattered around the globe. And, in a first for Boeing, large sections of the jet are built by these outside vendors and then joined together. That process, aimed at saving money, wasn't as smooth as Boeing had hoped. Parts weren't delivered on time, and the quality of some suppliers' products was poor.
Q: How much does the plane cost?
A: The 787-800 has a list price of $206.8 million, but airlines often negotiate discounts.
Q: How many passengers can fit on the plane?
A: It is designed to carry 210 to 250 passengers.
Q: How many 787s are there?
A: Boeing has delivered 50 planes so far. Another 798 are on order. The company is ramping up production to build 10 787s per month in Washington state and South Carolina by the end of the year.
Q: Is it normal for a new plane to have problems?
A: Any complicated piece of machinery has glitches at first. The Airbus A380, for instance, had an engine explode midflight in late 2010. However, the unique nature of the 787's construction -- and the increased media spotlight on this plane -- have regulators doing a more thorough review.
Boeing insists that the 787's problems are no worse than what it experienced when its 777 was new in the mid-1990s. That plane is now one of its top-sellers and is well-liked by airlines.
Q: What airlines fly the 787?
A: Japan's All Nippon Airways is the largest operator of the plane. United is the first U.S. airline customer with six. Air India, Ethiopian Airlines, Japan Airlines, LAN Airlines, LOT Polish Airlines and Qatar Airways also fly the plane.
Q: Where in the U.S. does the plane fly?
A: United Airlines is the only U.S. carrier to fly the plane. It flies between Los Angles and Tokyo and between various hubs such as Newark, N.J., and Houston and between Los Angles and Houston.
LOT had its inaugural 787 flight to the U.S. Wednesday, flying between Warsaw, the Polish capital, and Chicago.
All Nippon Airways flies from Seattle and San Jose, Calif., to Tokyo. Japan Airlines flies from Boston to Tokyo, and LAN flies from Los Angeles to Santiago, Chile. Ethiopian started flying the plane to Washington's Dulles International Airport in late September but put a different aircraft on that route in mid-December.
Q: What's at stake for Boeing?
A: Any more production delays could further upset the airlines that are eager to start flying the plane and cost Boeing millions of dollars in contractual penalties. If major changes are needed, the plane might weigh more, cutting its fuel efficiency. Orders could shift to the Airbus A350.
Q: What other problems could this mean for Boeing?
A: The 787's long range is one of its main selling points. The FAA limits how far twin-engine airplanes can fly so if the jet loses one engine, it can still fly long enough to make an emergency landing. The 787 already has approval for flights up to three hours away from any airport. Boeing wants to raise that to 5.5 hours, opening up routes across the Pacific. The FAA could now delay that approval.
Q: How is Boeing faring as a company? Is it making money? How's the stock price doing?
A: It's expected to report a 2012 profit later this month. Boeing reported a $1.39 billion profit for 2011, up from $1.16 billion in 2010. Almost half of its business is from defense.
Boeing shares fell $2.60, or 3.4 percent, to $74.34. Over the past year, they've traded between $66.82 and $78.02.
Q: Are passengers avoiding the plane?
A: A few are. United frequent flier Josh Feller said he changed his plans to fly a United 787 from Los Angeles International to Houston next month because of the 787's troubles.
"I've been following the 787 news closely and the latest incident finally spooked me into changing my flight," he said by e-mail. "It's an unnecessary risk and since I was going out of my way to fly the plane in the first place, decided to change flights." He also wanted to avoid any disruptions if United eventually grounds the 787.
Associated Press writers Joshua Freed in Minneapolis and Joan Lowy in Washington contributed to this report.