Investigators also said they were looking into the possibility that rescue crews ran over one of the two teenagers killed in the crash on Saturday. Officials released the details without explaining why the pilots were flying so slow — or why rescue officials didn't see the girl.
The Boeing 777 was traveling at speeds well below the target landing speed of 137 knots per hour, or 157 mph, said National Transportation Safety Board chief Deborah Hersman at a briefing Sunday on the crash.
"We're not talking about a few knots," she said.
Hersman said the aircraft's stick shaker — a piece of safety equipment that warns pilots of an impending stall — went off moments before the crash. The normal response to a stall warning is to increase speed to recover control.
There was an increase several seconds before the crash, she said, basing her comments on an evaluation of the cockpit voice and flight data recorders that contain hundreds of different types of information on what happened to the plane.
And at one-and-a-half seconds before impact, there was a call for an aborted landing, she said. The crash at San Francisco International Airport on Saturday killed two 16-year-old girls from China and injured dozens of others.
'Why was the plane going so slow?'
The new details helped shed light on the final moments of the airliner as the crew tried desperately to climb back into the sky, and confirmed what survivors and other witnesses said they saw: a slow-moving airliner.
Pilots normally try to land at the target speed, in this case 137 knots, plus an additional five more knots, said Bob Coffman, an American Airlines captain who has flown 777s. He said the briefing raises an important question: "Why was the plane going so slow?"
The plane's engines were on idle, Hersman said. The normal procedure in the Boeing 777, a wide-body jet, would be to use the autopilot and the throttle to provide power to the engine all the way through to landing, Coffman said.
There was no indication in the discussions between the pilots and the air traffic controllers that there were problems with the aircraft.
Among the questions investigators are trying to answer was what, if any, role the deactivation of a ground-based landing guidance system played in the crash. Such systems help pilots land, especially at airports like San Francisco where fog can make landing challenging.
'The plane will fall down'
The flight originated in Shanghai, China, stopped over in Seoul, South Korea, before making the nearly 11-hour trip to San Francisco. The South Korea-based airline said four South Korean pilots were on board, three of whom were described as "skilled."
Among the travelers were citizens of China, South Korean, the United States, Canada, India, Japan, Vietnam and France. There were at least 70 Chinese students and teachers heading to summer camps, according to Chinese authorities.
As the plane approached the runway under clear skies — a luxury at an airport and city known for intense fog — people in nearby communities could see the aircraft was flying low and swaying erratically from side to side.
On board, Fei Xiong, from China, was traveling to California so she could take her eight-year-old son to Disneyland. The pair was sitting in the back half of the plane. Xiong said her son sensed something was wrong.
"My son told me: 'The plane will fall down, it's too close to the sea,"' she said. "I told him: 'Baby, it's OK, we'll be fine."'
Rescue vehicle may have killed teen
The accident left many wondering how nearly 305 of the 307 passengers and crew members were able to make it out alive.
During the rescue effort, police officers threw utility knives up to crew members inside the burning wreckage of Asiana Airlines Flight 214 so they could cut away passengers' seat belts. Passengers jumped down emergency slides, escaping from thick billowing smoke.
Nearby, people who escaped were dousing themselves with water from the bay, possibly to cool burn injuries, authorities said. By the time the flames were out, much of the top of the fuselage had burned away. Inside The tail section was gone, with pieces of it scattered across the beginning of the runway. One engine was gone, and the other was no longer on the wing.
Amid the chaos, some urged fellow passengers to keep calm, even as flames tore through the Boeing 777's fuselage.
In the chaotic moments after the landing, when baggage was tumbling from the overhead bins onto passengers and people all around her were screaming, Wen Zhang grabbed her four-year-old son, who had hit the seat in front of him and broken his leg.
Spotting a hole at the back of the jumbo jet where the bathroom had been, she carried her boy to safety.
"I had no time to be scared," she said.
San Francisco Fire Department Chief Joanne Hayes-White credits the professionalism of the crew for the small loss of life.
"I think they had a very well trained crew," noted Hayes-White at a news conference earlier on Sunday. "From what I'm hearing, there wasn't a mad rush and people were literally trying to help each other and as orderly as possible to [get down] those chutes."
Hayes-White said the two teens who died were found on either side of the plane, but the San Mateo County Coroner is now investigating whether one of the girls may have been run over and killed by a rescue vehicle.
Coroner Robert Foucrault said an autopsy he expects to be completed by Monday will involve determining whether the girl's death was caused by injuries suffered in the crash or "a secondary incident."
Two passengers paralyzed
A doctor at San Francisco General Hospital says at least two people that were treated there are paralyzed and two others suffered road rash-type injuries suggesting they were dragged.
Chief of Surgery Margaret Knudson said doctors at the hospital have also seen abdominal and orthopedic injuries and head trauma.
She says patients with severe abdominal injuries and spinal fractures appear to have suffered them from being thrown forward and back while restrained by seat belts.
There are currently 19 people there, six in critical condition, including a child. Knudson said everybody who could talk to staff said they were in the back of the plane.
"When you heard that explosion, that loud boom and you saw the black smoke … you just thought, my God, everybody in there is gone," said Ki Siadatan, who lives a few kilometres away from the airport and watched the plane's "wobbly" and "a little bit out of control" approach from his balcony.
"My initial reaction was I don't see how anyone could have made it," he said.Chinese state media identified the dead as two 16-year-old girls who were middle school students in China's eastern Zhejiang province. China Central Television cited a fax from Asiana Airlines to the Jiangshan city government. They were identified as Ye Mengyuan and Wang Linjia.
Asiana President Yoon Young-doo said at a televised news conference that it will take time to determine the cause of the crash. But when asked about the possibility of engine or mechanical problems, he said he doesn't believe they could have been the cause.
Hersman said NTSB investigators will be on the scene for at least a week, but "if need be, we'll be here as long as it takes."
He said the plane was bought in 2006 but didn't provide further details. Asiana officials later said the plane was also built that year.
Company president apologizes
Yoon also bowed and offered an apology, "I am bowing my head and extending my deep apology" to the passengers, their families and the South Korean people over the crash, he said.
Four pilots were aboard the plane and they rotated on a two-person shift during the flight, according to The Ministry of Land, Infrastructure and Transport in South Korea. The two who piloted the plane at the time of crash were Lee Jeong-min and Lee Gang-guk.
Yoon, the Asiana president, described the pilots as "skilled," saying three had logged more than 10,000 hours each of flight time. He said the fourth had put in almost that much time, but officials later corrected that to say the fourth had logged nearly 5,000 hours. All four are South Koreans.
Asiana is a South Korean airline, second in size to national carrier Korean Air. It has recently tried to expand its presence in the United States, and joined the Star Alliance, which is anchored in the U.S. by United Airlines.
The 777-200 is a long-range plane from Boeing. The twin-engine aircraft is often used for flights from one continent to another because it can travel 12 hours or more without refuelling.
The most notable accident involving a 777 occurred on Jan. 17, 2008, at Heathrow Airport in London. British Airways Flight 28 landed hard about 1,000 feet short of the runway and slid onto the start of the runway. The impact broke the 777-200's landing gear. There were 47 injuries, but no fatalities.
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