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.
Deborah Hersman said 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, 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 began to examine whether the glide slope, a ground-based electronic landing aid, that was out of service at the airport may have contributed to the crash of the jetliner.
In a separate development, the San Mateo County coroner said he is looking into the possibility that fire rescue crews ran over one of the two teenager girls reported killed in the Saturday crash, the Associated Press reported. Coroner Robert Foucrault said an autopsy would determine whether the girl was dead when her body was struck on the runway.
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, 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,” 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 is not as precise as the information available to investigators from the plane’s flight data recorder, which the safety board began examining on Sunday. But the data provides 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 Sunday as two 16-year-old Chinese students on their way to a summer camp. The students, both girls, 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.
Several dozen people remain hospitalized, though many have been discharged. On Sunday, there were still 19 patients at San Francisco General Hospital and Trauma Center, down from 53 on Saturday. Of those, six, including one child, are critically injured, said Rachael Kagan, a hospital spokeswoman.
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.”
The flight had originated in Shanghai and left Seoul for San Francisco, the South Korean Ministry of Land, Infrastructure, and Transport said.
The two students, the Chinese news media reported, were from Zhejiang province in eastern China. Of the 291 passengers on board, 141 were Chinese, including at least 70 students and teachers on their way to summer camps, the Chinese news media reported.
Asiana Airlines identified the two students 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, the newspaper reported. Five teachers were accompanying the students.
In San Francisco on Sunday, federal investigators continued piecing together the events that led up to and caused the crash. Both flight data recorders have been sent to Washington, and investigators planned to have a preliminary readout soon, a spokeswoman for the National Transportation Safety Board, Kelly Nantel, said.
Hersman said there was no indication of a criminal act.
When the Asiana flight crashed, some of the normal landing aids on the airfield were out of service, but the landing should have been well within the capabilities of the airplane and the crew, aviation experts said.
A government official in Washington said that the Instrument Landing System, which electronically guides a pilot to the runway, had been out of service for several weeks because of construction at the end of the runway. Another system, which uses patterns of red and white lights to visually guide pilots, was in service, the official said.