SAN FRANCISCO -- It was pilot Lee Hang-kook’s first time landing a Boeing 777 San Francisco International Airport. A key part of the airport’s automated landing system was not working, so he was forced to visually guide the massive jetliner onto the runway.
Then something went terribly wrong.
As the jet sailed along westbound about 400 feet above the San Francisco Bay, its speed and altitude settings became grossly outside of its proper range. Aviation experts said those conditions should have led the pilot to pull up and go around for another try.
Instead, the jet continued on what appeared to be a seriously flawed final approach that experts said would have been virtually impossible to execute. Despite these red flags, Lee and his more experienced co-pilot on Asiana Airlines Flight 214 didn’t communicate problems until seconds before the plane hit a runway seawall, according to the National Transportation Safety Board.
Details emerging about the plane’s final seconds have both investigators and aviation safety experts focusing on why the crew did not address the grave situation they were facing much earlier.
“There was no discussion of any problems clearly at a time when one was developing. Both pilots should have seen that something was going wrong,” said Barry Schiff, a former TWA pilot for 34 years and an aviation safety expert. “Why didn’t one of them say or do something?”
The NTSB plans to interview all four pilots aboard the aircraft, the two at the controls and two relief pilots for the long flight. Deborah A.P. Hersman, chairwoman of the National Transportation Safety Board, said Monday that investigators will closely examine the crew’s coordination in the cockpit.
“We're looking at what they’re doing and why they were doing it,” Hersman said. “We want to know what they understood.”
Hersman said the Asiana jetliner had fallen more than 30 knots below its target landing speed in the seconds before it crashed, even as the crew desperately tried to apply more engine power.
But even before that point had been reached, the plane had departed from a stable and planned approach to the runway, failing to keep up with its intended 134 knots to 137 knots speed at 500 feet over the bay.
Michael L. Barr, an aviation safety expert and former military pilot who teaches at USC, said at 500 feet the pilots should have had a stable approach, in which the aircraft was on its proper glide slope, on course to the center line of the runway and at its proper air speed. Otherwise, the landing should have been aborted and a “go around” taken for another attempt.
Pilots can sometimes be reluctant to abort a landing, even when the approach is unstable, Barr said. Although pilots have improved in their willingness to abort a bad approach, it remains a problem in the industry.
The Flight Safety Foundation, a Washington-based organization that advocates for airline safety, said in a recent published report that 97% of the time pilots do not abort from an unstable approach. The reasons pilots most often cite for the decision not to abort a flight is their experience and competency to recover.
But Lee, the pilot controlling the Boeing 777, had only 43 hours of experience in that type of jet, although he had many thousands of hours in other Boeing aircraft, including the 747. He was being supervised by the more experienced Capt. Lee Jung-min, though he also did not call for a go-around until 1.5 seconds before the crash, far too late for the abort to occur.
By then, the aircraft’s systems were already warning that it was near stall, a condition where the plane does not have enough lift to continue flying.
Only seconds earlier, Lee Jung-min had called for more engine power, but that also came too late.
Barr said that the powerful engines on big jetliners can take up to 10 seconds to go from idle to full thrust.
“Ten seconds when you are low to the ground is like a lifetime,” Barr said.
At three seconds before impact, the speed of the jet dropped to 103 knots and the engines were spooling up but still at only 50% of full power. The jet’s aft fuselage clipped the sea wall and the plane slammed into the ground, killing two and injuring more than 180.
Investigators were combing through the wreckage Monday. The lower portion of the plane's tail cone is on the rocks at the sea wall, officials said, and a “significant piece” of the tail is in the water. More pieces of the airplane are visible in the water when the tide goes out. At the beginning of the tarmac, investigators found the horizontal stabilizer, the vertical stabilizer and the upper portion of the tail cone.
Further down Runway 28L, investigators have documented pieces of the landing gear and fractured pieces of the aft fuselage, as well as sea wall debris several hundred feet away from the wall.
The San Francisco airport’s glide path instruments were taken out of service in June for construction, though the crew had two other automated systems to help them make a smooth landing.
But flight crews have become increasingly reliant on the automated systems, and in many cases, jetliners execute fully automated landings. In the process, crews are at risk of losing their proficiency to handle the complex jobs without the instruments.
The lack of the automated systems should not have been a problem, said Jared Testa, chief flight instructor at Embry-Riddle Aeronautical University’s Arizona campus.
“In the U.S., pilots are trained in stick and rudder skills and looking out the window of the airplane,” he said. “A visual approach should not be unfamiliar to a pilot. They are taught that from the very beginning. We instill the idea of stable approaches from day one.”
If the communications in the cockpit broke down, investigators and researchers will be looking for company policies or even cultural issues that may have caused the problem. Aviation safety studies have documented that in certain cultures junior pilots are reluctant to question authority, which violates the whole concept of cockpit management, said Najmedin Meshkati, an engineering safety expert at USC.
The Asiana is “an unfortunate textbook example” of questionable cockpit decision making during what pilots call “short final” approach. “Because of the high tempo of operations, there is not way you can recover. That’s why all your decisions have to be perfect. There is no time for discovery of your error or recovery from your error.”
Meanwhile, the Air Line Pilots Assn. said the factual disclosures about crash by NTSB were “unprecedented” and “encourages wild speculation, as we have already seen in the media about the causes of the accident before all the facts are known.”
Vartabedian and Weikel reported from Los Angeles, Nelson from San Francisco.