The National Transportation Safety Board has revealed that as the plane was traveling at a speed of just 118 miles per hour as it approached SFO, 40 miles an hour slower than the target approach speed. A significant piece of the tail of the aircraft was discovered in the water at the end of the runway, and other plane parts were visible at low tide. NTSB Chairwoman Deborah Hersman says other debris from the seawall was found several hundred feet up the runway.
NTSB investigators are gathering evidence and doing precision mapping of the accident scene. At the same time, at the NTSB's Washington D.C. lab, groups are convening to transcribe key parts of the cockpit voice recording.
"We want to have people on that cockpit voice recorder transcription group who are familiar with the aircraft and any noises or sounds or alerts that might come from that aircraft," Hersman said.
Also Monday, the NTSB began interviewing the three captains and one first officer responsible for flying the plane.
"Who was the pilot flying, who was the pilot in command, at the time of the accident," Hersman said.
Asiana spokeswoman Lee Hyomin said that Lee Gang-guk, who was at the controls, had nearly 10,000 hours flying other planes but only 43 in the 777, a plane she said he still was getting used to flying. Another pilot on the flight, Lee Jeong-min, had about 12,390 hours of flying experience, including 3,220 hours on the 777, according to the Ministry of Land, Infrastructure and Transport in South Korea. Lee was the deputy pilot, tasked with helping Lee Gang-guk get accustomed to the 777, according to Asiana Airlines.
Two other pilots were aboard, with teams rotating at the controls.
The plane's Pratt & Whitney engines were on idle and the pilots were flying under visual flight rules, Hersman said. Under visual flight procedures in the Boeing 777, a wide-body jet, the autopilot would typically have been turned off while the automatic throttle, which regulates speed, would have been on until the plane had descended to 500 feet (150 meters) in altitude, Coffman said. At that point, pilots would normally check their airspeed before switching off the autothrottle to continue a "hand fly" approach, he said.
There was no indication in the discussions between the pilots and the air traffic controllers that there were problems with the aircraft.
What the crew says will be compared against the voice and data recordings.
"Whether they were hand flying the airplane, whether the autopilot was on, reliance on the cockpit automation and how well they understood the automation and what it was supposed to do," Hersman said.
Asiana and the Korean equivalent of the NTSB will also be present at those interviews.
Preliminary information from the data recorder shows auto pilot was disengaged at 1,600 feet, but in the next one minute and 22 seconds to impact, the airspeed dropped dramatically to well below the target. Investigators will be asking the crew why.
"We're looking at what they were doing and we want to understand why they were doing it, we want to understand what they knew and what they understood," Hersman said.
First responders share stories
When the Asiana Airlines flight went down on Saturday, more than 200 firefighters and police officers rushed into action. Monday, some of those first responders shared their experiences.
"It was so surreal; so much chaos and yet it was quiet," San Francisco Police Lt. Gaetano Caltagirone said.
"We rounded the terminal and all you could see across the airfield was dark smoke and a plane on its belly," San Francisco Fire Lt.Dave Monteverdi said.
They knew the drill still nothing quite prepared the 268 men and women for the challenges they faced.
"Flight attendants were trying to help and started yelling if we had some knives; they needed knives," San Francisco Police Ofc. Jim Cunningham said.
Cunningham tossed his up to help cut passengers from their seat belts and then ran into the smoking plane, not once but twice, with no special breathing apparatus.
"You look at somebody, they're not really screaming, but moaning in pain; I couldn't walk away from that," he said.
The relief over saving lives is tempered by the possibility that a rescue rig may have actually run over one of the two girls who died.
"It hurts a lot, it does," San Francisco Fire Asst. Chief Tom Siragusa said. "But let's let the investigation play out."
Chinese state media and Asiana have identified the girls as Ye Mengyuan and Wang Linjia, students at Jiangshan Middle School in Zhejiang, an affluent coastal province in eastern China.
They were part of a group of 29 students and five teachers from the school who were heading to a summer camps in Southern California, according to education authorities in China. That camp has been cancelled.
Robert Foucrault, the coroner, said one of the bodies was found on the tarmac near where the plane's tail broke off when it slammed into the runway. The other was found on the left side of the plane about 30 feet (10 meters) away from where the jetliner came to rest after it skidded down the runway. Foucrault originally had planned to release a preliminary cause of death for each of them on Monday, but decided to wait until he could do a broader inquiry that will include reviewing written information from the public safety agencies that responded to the crash, audio dispatch files and perhaps interviews.
The flight originated in Shanghai, China, and stopped over in Seoul, South Korea, before making the nearly 11-hour trip to San Francisco.
The Associated Press contributed to this report.