WASHINGTON (AP) -- The investigation into the crash-landing of an Asiana Airlines flight at San Francisco's airport last summer has highlighted problems with cockpit culture and the trainee pilot's lack of confidence in his ability to safely land the Boeing 777.
Thousands of pages of investigative documents released during a National Transportation Safety Board hearing Wednesday revealed that pilot Lee Kang Kuk harbored fears about landing safely while relying on manual controls and a visual approach, but he didn't express them to his fellow crew members because he didn't want to fail his training mission and embarrass himself.
The agency is probing the cause of the July 6 crash that killed three people. More than 300 people survived the wreck, the vast majority without major injuries.
The top official at the NTSB said investigators are examining an apparent lack of communication in the cockpit and signs of confusion among the pilots about the jetliner's elaborate computer systems.
Junior officers' reluctance to speak up has been an issue in past accidents, though industry training has tried to emphasize that safety should come first.
"It's never one thing. It's always several hazards coming together with a catastrophic result," said Tom Anthony, director of the aviation safety program at the University of Southern California. "You can see that the areas of concern to the NTSB are the effects of automation and also communication in the cockpit — whether (pilots) are communicating hazards to other crew members."
Airlines will be forced to examine cockpit culture, Anthony said. The U.S. went through that decades ago and shook off a "captain-as-overlord" mentality, he said, and now some Asian airlines will have to make sure their training encourages even junior pilots to speak up about hazards.
Asiana officials declined to discuss cockpit culture or any confusion about the jet's computer controls. But in a statement they expressed "sorrow for the loss of life and the injuries sustained in the accident" and said they are "taking the steps necessary to ensure that such an accident never happens again."
Lee, a veteran pilot undergoing training on the wide-body 777, told investigators he had been "very concerned" about attempting a visual approach without instrument landing aids, which were turned off because of runway construction. A visual approach involves lining up the jet for landing by looking through the windshield and using other cues, rather than relying on a radio-based glideslope system that guides the aircraft to the runway at the proper angle.
Lee said he had worried privately before takeoff about his ability to handle the plane. But he told investigators he did not speak up because others had been safely landing at San Francisco International Airport under the same conditions. As a result, he said, "he could not say he could not do the visual approach."
Another Asiana pilot who had recently flown with Lee told investigators he was not sure if he was making normal progress. That pilot said Lee, who had less than 45 hours in the 777 jet, did not perform well during a trip two days before the accident and he was "not well organized or prepared," according to the investigative report.
"This pilot should never have taken off," said attorney Ilyas Akbari, whose firm represents 14 of the passengers. "The fact that the pilot was stressed and nervous is a testament to the inadequate training he received, and those responsible for his training and for certifying his competency bear some of the culpability."
During its approach, Asiana Flight 214 came in too low and too slow, then clipped a seawall, breaking off part of its tail. Neither Lee nor an instructor pilot in the cockpit had said anything when the first officer raised concerns four times about the plane's rapid descent.
NTSB Chairman Deborah Hersman said the agency has not yet determined the cause of the crash. So far, the investigation has not found any mechanical problems, although testing is ongoing, NTSB investigator Bill English said.
But documents released Wednesday cataloged other issues that could have played a role in the crash, such as a culture of not acknowledging weakness and of deferring to a higher-ranking colleague.
Lee told NTSB investigators he did not immediately move to abort the landing and perform a "go-around" because he felt that only the instructor pilot had the authority to initiate that emergency move.
Lee also said he had been blinded during a critical instant before the botched landing by a piercing light from outside the aircraft. NTSB investigators repeatedly asked about the light, but he was unable to pinpoint its origin or how it precisely affected him.
Asked whether he wore sunglasses in the cockpit, Lee said he did not "because it would have been considered impolite to wear them when he was flying with his" instructor. The instructor pilot told investigators he never saw a bright light outside the aircraft.
Recordings from the cockpit show Lee took the controls about 1,500 feet above San Francisco Bay. Though he was an experienced pilot with the Korea-based airline, it was his first time piloting an airliner into San Francisco's airport since 2004, according the NTSB.
The plane's first officer, Bong Don Won, told NTSB investigators that as the plane started its descent, he noticed its "sink rate" was too rapid. He said that he said nothing at that point, but as the plane's altitude dropped below 1,000 feet, he advised the crew four times about the rapid descent. The cockpit recorder showed no response from the others, though the first officer said the pilot deployed the plane's flaps, which appeared to slow the plane's drop.
The crew did not comment again on the jet's low approach until it reached 200 feet above the ground, according to a transcript of the cockpit voice recording.
Lee conceded to investigators that he was worried about his unfamiliarity with the 777's autoflight systems. He admitted he had not studied the systems well and thought the plane's autothrottle was supposed to prevent the jet from flying below minimum speed as it neared the runway.
NTSB investigators also raised concerns about the design of the 777's controls, warning that the plane's protection against stalling does not always automatically engage.
When the plane's autothrottle is placed in a "hold" mode, as it was during the Asiana flight, it is supposed to re-engage or "wake up" when the plane slows to its minimum airspeed.
Boeing Co.'s chief of flight deck engineering, Bob Myers, testified that the company designed the automated system to aid — not replace — the pilot. If there's a surprise, he said, "we expect them to back off on the automation" and rely on their basic skills.
Boeing evacuation engineer Bruce Wallace testified that at least one, if not two, of the passengers who died did not have seat belts on.
Wallace also said inflatable rafts deployed inside the jet, pinning at least one flight attendant in the wreckage. Engineers had never seen that happen before and were looking at safety improvements.
One of the three fatalities was a teenage girl from China who survived the crash but become covered in firefighting foam and got hit by an emergency vehicle on the runway.
Documents released Wednesday revealed that Ye Meng Yuan was struck twice — once by a fire rig spraying foam and again 11 minutes later by a second truck that was turning around to fetch water.
Mendoza reported from San Jose, Calif., and can be reached at https://twitter.com/mendozamartha . AP Airlines Writer David Koenig in Dallas contributed to this report.