The 787 has been in operation for 15 months, and Boeing has delivered 50 airplanes so far to eight airlines, including All Nippon Airways, Japan Airlines and United Airlines. Since then, a small number of 787s have had electrical fires, fuel leaks or other problems, prompting a safety advisory from federal regulators and a formal investigation into an electric fire this week. The National Transportation Safety Board is trying to find out why a fire broke out near a battery pack in the auxiliary power unit in a 787 parked at Logan International Airport in Boston on Monday. The fire occurred in a Japan Airlines plane after the passengers and crew had gotten off.
On Tuesday, another of the airline’s 787s, also in Boston, was delayed for nearly four hours after a fuel leak. And on Wednesday, All Nippon canceled a domestic flight after a computer on board erroneously showed problems with the plane’s brakes. These problems followed the forced diversion of a United Airlines 787 in December after one of its six electric generators failed in midflight.
Mike Sinnett, the 787’s chief project engineer, said on Wednesday that the program suffered from no more problems than any other new plane, like Boeing’s 777 when it was introduced in the mid-1990s. He defended the company’s choice to use lithium-ion batteries, saying Boeing was not looking for alternatives to them. And he said the 787 had a large number of redundant systems, meaning that if one or more failed, the plane could still fly and land safely. Testing demonstrated the 787 could fly for more than five and a half hours with just one electrical generator functioning.
“This is par for the course for any new airplane program,” Mr. Sinnett said in a conference call with reporters. “We have a responsibility and obligation to help assure people about the integrity and the robustness of the design.”
Asked whether the plane was safe, he responded: “Absolutely. I am 100 percent convinced the airplane is safe to fly. I fly on it myself all the time.”
Boeing declined to answer specific questions about Monday’s fire, citing the continuing investigation.
The 787’s operational reliability — a measure of how often it leaves the gate on time without a mechanical problem — is in the high 90 percent range, he said, a rate similar to the 777’s at the same time in its production life.
Potential problems with the electrical systems and batteries could be significant, because the 787 carries a lot more technology than previous generations of airplanes. It makes extensive use of lightweight carbon composites, has more fuel-efficient engines and relies mostly on electrical systems instead of mechanical ones to operate hydraulic pumps, de-ice the wings, pressurize the cabin and handle other tasks. It also has electric brakes instead of hydraulic ones.
Instead of drawing air from the engines to run these systems, the 787’s novel architecture eliminates most pneumatic systems and replaces them with electric ones. This increases the fuel efficiency of the airplane by 2 to 3 percent at cruising altitude, according to Boeing. Randy Tinseth, Boeing’s head of marketing, said in a statement on Tuesday that the 787 had logged more than 18,000 flight cycles and flown more than 50,000 hours.
Boeing shares, which had dropped more than 5 percent in the last two days, recovered partly on Wednesday, and were up 3.6 percent at $76.76.
Article source: http://www.nytimes.com/2013/01/10/business/boeing-defends-safety-of-787.html?partner=rss&emc=rss