This morning, the National Transportation Safety Board released their findings compiled from flight data, voice recordings, and interviews for the 2013 crash of Asiana 214, a Boeing 777-200ER, which resulted in the loss of three lives.
"The flight crew over-relied on automated systems that they did not fully understand. As a result, they flew the aircraft too low and too slow and collided with the seawall at the end of the runway." said acting NTSB chairman Christopher Hart.
On approach to San Francisco (SFO), the pilot flying the plane noticed they were too high, and set the descent rate to -1500 feet per-minute in autopilot. Six miles from SFO, the descent rate was changed back to -1000FPM, as they still flew higher than they should have been. Five miles out, they were 400 feet above the glideslope path they should have been on, and they lowered the flaps to 20 degrees as the engines hummed along just above idle.
At 1700 feet, the pilot flying the plane requested flaps 30, but the copilot noted their speed was still too high. At just above 1500 feet, the pilot at the controls put the autopilot into Flight Level Change mode, causing the plane to begin a climb to 3,000 feet. The pilot then disengaged the autopilot and set the thrust to idle. At this point, they were at 1,300 feet and three miles away from SFO. The auto-throttle was in HOLD mode, meaning the pilot should have been controlling the plane's speed.
At the NTSB hearing this morning, the pilot flying the 777-200ER, Lee Kang Kuk, told the board that he was "astonished" that the auto-throttle did not maintain speed during approach, in spite of being in HOLD mode.
At around two miles out, the sink rate (speed at which they were descending, measured in feet per-minute) had increased to 1500FPM. The observer pilot alerted the pilot at the controls to this. At this point, they were cleared to land, still above glide slope but sinking quickly.
1.4 miles from the runway, the plane ended up being lower than the glide slope, and 122 knots - 15 knots slower than the desired speed. The pilot began pulling the nose up, to maintain the glide path, but this caused the plane to slow even more. The crew received an airspeed warning, eleven seconds before impact. At seven seconds before impact, the copilot set the thrust levers to full thrust. They were 32 knots too slow. They received a call to abort the landing and go around, but they could not gain enough altitude to clear the seawall.
This is obviously a case of pilot error, but in addition some experts are suggesting that the complexities of Boeing's autopilot on the 777 somehow overwhelmed or confused the pilots. To that, I say the pilots were poorly trained.
During today's NTSB hearing, investigators also noted that crew fatigue could have played a role in the decision making. "There was evidence of some sleep restriction on the pilot flying, and all three pilots had circadian rhythm disruptions." It was 3:30AM in Seoul at the time of the crash, and pilots exhibited slower psychomotor reaction times and memory problems.
Top image - Asiana 214 wreckage, via Getty Images.