Pilots’ cockpit actions under review
SAN FRANCISCO — It was pilot Lee Hang-kook’s first time landing a Boeing 777 at San Francisco International Airport, and with a key part of the airport’s automated landing system not working, he was forced to visually guide the massive jetliner onto the runway.
As Asiana Airlines Flight 214 approached the airport 400 feet above San Francisco Bay, it was flying too low and too slow. That should have been a warning to the pilot to abort the landing and make another attempt, aviation experts said.
But Lee didn’t abort. What was even more baffling: He and the more experienced co-pilot next to him didn’t discuss their predicament. Cockpit voice recordings show the two didn’t communicate until less than two seconds before the plane struck a sea wall and then slammed into Runway 28L.
Investigators and aviation safety experts focused Monday on why the crew did not recognize the danger they faced and take action.
“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 TWA pilot for 34 years and now an aviation safety expert. “Why didn’t one of them say or do something?â€
The National Transportation Safety Board 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 NTSB, 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.â€
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 aircraft had departed from a stable and planned approach to the runway, failing to keep up with its intended speed of 134 to 137 knots at 500 feet over the bay.
Michael L. Barr, an aviation safety expert and former military pilot who teaches at USC, said that 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 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 Washington, D.C.-based Flight Safety Foundation, which advocates for airline safety, said in a recent published report that 97% of the time, pilots do not abort a flight from an unstable approach. The reasons they most often cite are their experience and competency to recover.
But Lee, the pilot at the controls of 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 too 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 in which it 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 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,†he said.
At three seconds before impact, the jet’s speed 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 dozens more.
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 plane are visible in the water when the tide goes out. At the edge of the tarmac, investigators found the horizontal stabilizer, the vertical stabilizer and the upper portion of the tail cone.
Farther 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.
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 with their own skills.
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.â€
If 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 entire concept of cockpit management, said Najmedin Meshkati, an engineering safety expert at USC.
The Asiana accident is “an unfortunate textbook example†of questionable cockpit decision-making during what pilots call “short final†approach, Meshkati said. “Because of the high tempo of operations, there is no 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.â€
Meanwhile, the Air Line Pilots Assn. said the factual disclosures about the crash by the 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.â€
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Vartabedian and Weikel reported from Los Angeles, Nelson from San Francisco.
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