Former 777 pilot calls San Francisco crash ‘close to inexplicable’
Just what happened in the cockpit of the Asiana flight that crashed while attempting to land at a San Francisco airport Saturday will undoubtedly be a big part of the crash investigation. The 777’s strong safety record and the fact that they had four experienced pilots at the helm has some scratching their heads about what went wrong.
“This is really close to inexplicable,” said aviation expert and retired Alaska Airlines pilot John Nance, in an appearance on 770 KTTH’s David Boze Show.
Nance said in the last 30 years, technology and the cockpit culture have evolved to recognize the potential for human error. Automated flying technologies and a collaborative crew are in place to minimize mistakes that could be made by one individual.
“The basic idea is we turn to the captain and say, ‘We’re onto you Bub. We know you are human. You can’t be perfect, and consequently, we’re not going to allow you to run this airplane with one carbon-based brain. We want you to take into account what your co-pilot thinks.'”
Witnesses of the crash reportedly noticed the plane flying much slower than normal on landing.
Indeed, National Transportation Safety Board Chairman Deborah Hersman said the plane was well under its target speed of 137 knots approaching the runway.
According to flight data, automated warning systems even alerted the pilots to the slow speed. Four seconds before the crash, the pilots received an automated stick shaker warning that the plane was about to stall.
“When you get the stick shaker, you are about five knots away from aerodynamic stall,” said Nance. “That means that the aircraft has slowed down so much, and the nose has been pitched up so far to maintain level flight, that the air begins to separate over the top of the wings and you lose lift and literally fall out of the sky.”
Nance can’t understand why none of the pilots made corrections.
“Were the other three pilots in the cockpit reluctant to say something when they clearly saw they were too low? They had to, it was a visual day,” said Nance.
Visibility was about 10 miles in the area at the time of the crash.
Nance, who is familiar with flying 777’s, said after they received the warning, even more automated technologies should have come into play to increase the plane’s speed.
“If you don’t take action, it will then push the yoke forward to try to get out of the stalled condition. I don’t know if that operated in this particular case, but there is another element in the 777 that should cause the throttles to snap up and the engines to rev up because the airplane itself is programmed not to stall if it can predict that.”
Nance said there are a lot of questions as to why the human and technological safeguards didn’t prevent this crash.