SAN FRANCISCO -- The chairwoman of the National Transportation Safety Board said Sunday that pilots of the Asiana Airlines jetliner that crashed a day earlier in San Francisco tried to abort the landing just seconds before the crash.
The safety board chairwoman, Deborah Hersman, said Sunday at a briefing that a crew member called for an increase in speed seven seconds before the plane clipped an embankment at the edge of the runway. She said the plane was traveling well below the speed needed to maintain a stable angle of approach. The jetliner's cockpit recorder included the sounds of an automatic shaking of the throttle just before the crash, an indication that the plane was about to stall.
The device also recorded a voice command calling for a go-round 1.5 seconds before the crash. While the engines responded normally, the move came too late to prevent the crash, Ms. Hersman said. The plane's tail section then snapped off, and the plane skidded across the runway and caught fire.
Her comments came as investigators also began to examine whether an electronic landing aid that was out of service at the airport may have contributed to the crash of the jetliner. Ms. Hersman's description of how the plane's forward momentum slowed generally tracks other data showing the jetliner began to descend too fast because it did not have enough airspeed. Data collected by an aviation firm suggested that the plane was descending more than four times faster than normal shortly before it crashed.
At 800 feet over San Francisco Bay, the plane was descending at 4,000 feet a minute on Saturday, according to data gathered from FlightAware, a company that listens to navigation broadcasts and sells the data to airlines and others. The normal approach profile is 600 to 800 feet a minute.
At the briefing, Ms. Hersman focused mainly on whether the pilots erred while making a series of calculations needed to land.
While the pilot should have recognized the abnormally strong descent, the safety board also said Sunday that it was investigating whether construction at the airport -- which had temporarily shut down an electronic system that helps guide pilots to the proper landing slope -- might have played a role in the crash.
"The glide slope had been out since June," Ms. Hersman said on CBS's "Face the Nation."
"We're going to take a look into this to understand it," she said. "But what's important to note is there are a lot of tools that are available to pilots."
FlightAware's data are not as precise as the information available to investigators from the plane's flight data recorder, which the safety board began examining Sunday. But the data provide an indication that in the last moments of the flight, unless there was some as-yet undisclosed mechanical problem, crew members, from their own instrumentation, should have been aware that the plane was descending too fast.
Aviation experts said that the pilots, who were both veterans, could also have relied on red and white signal lights on the runway to visually guide the plane to touch down or, if they chose, rely on the plane's onboard computers to generate the angle of approach.
Witnesses and passengers have described the jetliner as coming in too low and clipping a rocky embankment at the edge of the water just before the runway. The plane's tail section then snapped off and the plane skidded across the runway and caught fire.
Two passengers were killed and at least 180 people were injured. The dead passengers were identified on Sunday as two 16-year-old Chinese girls on their way to a summer camp. They were believed to have been seated toward the back of the passenger jet, the president of airline, Yoon Young-doo, said. Their bodies were found on the runway.
Mr. Yoon said Asiana Airlines did not believe there was anything wrong with the Boeing 777, which had been bought in 2006.
"So far, we don't believe that there was anything wrong with the B777-200 or its engine," he said. He also apologized for the crash, saying, "We are deeply sorry for causing the trouble."
Asiana Airlines identified the two girls as Ye Meng Yuan and Wang Lin Jia. They were among 30 high school students from the town of Jiangshan who were planning to attend a 15-day English language program at California universities, the Oriental Morning Post, a Shanghai newspaper, reported. The school has been organizing similar summer programs for more than a decade for students who typically pay about $5,000 to attend, the newspaper reported. Five teachers were accompanying the students.
Several dozen people remain at area hospitals, though many have been discharged.
The force of the crash fractured the spines of several passengers, causing paralysis in some cases, according to Margaret Knudson, chief surgeon at San Francisco General Hospital and Trauma Center. Others, she said, had severe road rash as if they had been dragged. She said doctors had expected to see burns, but that there were few.
Of the patients who could speak, she said, all said they were in the back of the plane when it crashed.nation
Lowy reported from Washington, D.C. Associated Press writers Terry Collins, Terry Chea and Sudhin Thanawala in San Francisco, David Koenig in Dallas and Louise Watt in Beijing contributed to this report. First Published July 6, 2013 9:15 PM