Both flight data recorders have been recovered, the National Transportation Safety Board said, from wreckage left by yesterday's tragedy that left two 16-year-old passengers from China dead.
Survivors and witnesses reported the 7-year-old Boeing 777 appeared to be flying too low as it approached the end of a runway near the San Fransisco bay.
"Stabilised approaches have long been a safety concern for the aviation community," NTSB Chairman Deborah Hersman told CNN, saying they represent a significant threat. "We see a lot of runway crashes."
Internal damage to the plane is "really striking," she said.
Nothing, including pilot error, has been ruled out as a possible cause of the crash, investigators said. The recorders have already arrived at an NTSB lab in Washington for analysis.
Teen girls Ye Mengyuan and Wang Linjia, both Chinese nationals, were killed in the crash, Asiana Airlines said today. There were 291 passengers and 16 crew members aboard the two-engine jet, which had flown a 10-hour direct flight from Seoul, South Korea.
Airport technology called the Instrument Landing System -- or ILS -- which normally would have helped pilots correctly approach the runway -- were not operating at the time, CNN, quoting officials, said.
"There are a lot of systems that help support pilots" as they fly into busy airports, Hersman said. Some of these systems alert the pilots. "A lot of this is not necessarily about the plane telling them" that something may be wrong, she said.
Evidence in the investigation will include data that show what action the pilots took during the approach to the airport. The pilot operating the aircraft was a veteran who had been flying for Asiana since 1996, the airline said.
