In the left seat of the cockpit sat Lee Gang-kuk, a 46-year-old pilot with 35 hours of experience flying a Boeing 777 who was landing the big jet for his first time at San Francisco International Airport. The flight came to a tragic end when the airliner, which came in too low and too slow, crash-landed on Saturday, killing two passengers and injuring many others as it skittered and spun 100 feet. Investigators trying to piece together what went wrong are looking at the pairing of the pilots, who were assigned to work together through a tightly regulated system developed after several deadly crashes in the 1980s were blamed in part on inexperience in the cockpit. They will also be examining their working relationship, said National Transportation Safety Board chairman Deborah Hersman on Wednesday. "We are certainly interested to see if there are issues where there are challenges to crew communication, if there's an authority break in where people won't challenge one another," she said. Pilots are trained to communicate their concerns openly, she said, "to make sure that a junior pilot feels comfortable challenging a senior pilot and to make sure the senior pilot welcomes feedback in a cockpit environment from all members of the crew and considers it." The NTSB has now concluded interviews with all four pilots who were aboard the plane. Hersman said Wednesday the pilot trainee told investigators he was blinded by a light at about 500 feet, which would have been 34 seconds before impact and the point at which the airliner began to slow and drop precipitously. It was unclear, however, whether the flash might have played a role in the crash. Hersman also said that a third pilot in the jump seat of the cockpit told investigators he was warning them their speed was too slow as they approached the runway. And she said when the plane came to a stop, pilots told passengers to stay seated for 90 seconds while they communicated with the tower as part of a safety procedure. Hersman said this has happened after earlier accidents and was not necessarily a problem. People did not begin fleeing the aircraft until 90 seconds later when a fire was spotted outside the plane. Hersman stressed that while the trainee pilot was flying the plane, the instructor was ultimately responsible, and thus the way they worked together will be scrutinized. "That's what the airline needs to do, be responsible so that in the cockpit you're matching the best people, especially when you're introducing someone to a new aircraft," former NTSB Chairman James Hall said. Massachusetts Institute of Technology aeronautics professor Mary Cummings said it's common for two commercial pilots who have never worked together before to be assigned to the same flight. But she said the military tries to have crews work together more permanently. The skillful flying of captain Chesley "Sully" Sullenberger and teamwork between Skiles and Sullenberger was credited for a water landing on the Hudson River that saved the lives of all aboard. Details emerging from Asiana pilot interviews, cockpit recorders and control-tower communications indicate that Lee Gang-kuk, who was halfway through his certification training for the Boeing 777, and his co-pilot and instructor, Lee Jeong-Min, thought the airliner's speed was being controlled by an autothrottle set for 157 mph. In the last two minutes, there was a lot of use of autopilot and autothrusters, and investigators are going to look into whether pilots made the appropriate commands and if they knew what they were doing, she said. "There are two pilots in the cockpit for a reason," she said Wednesday. They're there to fly, to navigate, to communicate and if they're using automation a big key is to monitor. As the trainee pilot flew, she said, the instructor captain, who is ultimately responsible for flight safety, was tasked with monitoring. The third pilot was in the cockpit jumpseat also to monitor the landing. Crash survivor Brian Thomson, who was returning from a martial arts competition in South Korea and walked away physically unscathed, said he's not concerned about the pilot's lack of experience with the airliner. A dozen survivors remained hospitalized Wednesday, half flight attendants, including three thrown from the airliner during the accident. One has been identified as 25-year-old Maneenat Tinnakul, whose father told the Thairath newspaper in Thailand she suffered a minor backache. Another flight attendant, Sirithip Singhakarn, was reported in intensive care. Meanwhile, fire officials continued their investigation into whether one of their trucks might have run over one of the two summer camp bound Chinese teenagers, Wang Linjia and Ye Mengyuan, killed in the crash. Citing similarities to a February 2009 fatal U.S. airline crash near Buffalo, N.Y., two New York Democrats - Sen. Charles Schumer and Rep. Brian Higgins - on Wednesday called on the Federal Aviation Administration to issue long-delayed safety regulations that would require pilots to undergo more extensive training on how to avoid stalling accidents. "While the (Asiana) investigation is still ongoing, one thing is clear, this crash and the other recent crashes like Flight 3407 demonstrate a troubling pattern in which pilots are mishandling air speed, which can lead to fatal stalls," Schumer said.